How animals understand numbers influences their chance of survival

While they can't pick out precise numbers, animals can comprehend that more is, well, more. From birds to bees and wolves to frogs, animals use numbers to hunt, find a mate, return to their home, and more -- and researchers believe that this ability to process and represent numbers, known as numerical competence, plays an important role in how animals make these decisions and influences an animal's chance of survival. In a Review publishing March 30 in the journal Trends in Ecology and Evolution, Andreas Nieder, a neurobiologist at the University of Tuebingen, Germany, explores the current literature on how different animal species comprehend numbers and the impact on their survival, arguing that we won't fully understand the influence of numerical competence unless we study it directly.

"Interestingly, we know now that numerical competence is present on almost every branch on the animal tree of life," says Nieder, who works with different animal species to explore how trained animals discriminate and represent numbers as well as how numbers are represented in the brain. "Different groups of animals obviously developed this trait independently from other lineages and that strongly indicates that it has to be of adaptive value. So the capability to discriminate numbers has to have a strong survival benefit and reproduction benefit."

Honeybees, for instance, can remember the number of landmarks they pass when searching for food in order to find their way back to the hive. "The last common ancestor between honeybees and us primates lived about 600 million years ago," he says. "But still, they evolved numerical competence that, in many respects, is comparable to vertebrae numerical competence."

This can also be seen in animals choosing a larger amount of food over a small amount or in animals forming hunting alliances. Wolves are more likely to hunt successfully if they have the right number of wolves in their pack for the size of their prey: with prey like elk and moose, only around six to eight wolves are needed, while hunting bison requires a pack of nine to thirteen. Their prey also use this concept to protect themselves from predators -- elk tend to live in smaller herds, which rarely have encounters with wolves, or gather in large herds to reduce the chance of any individual becoming prey. "So obviously they are assessing the number of individuals in their groups for their everyday life situations," Nieder says.

Furthermore, it has been shown that numerical competence even plays a role in attracting a mate. For example, male frogs sing "advertisement" calls to attract females. The females, listening for the complexity of their calls, choose the male that sings the most "chucks" in their mating call. Even once they've attracted a mate, species like the mealworm beetle and the cowbird use numerical competence to increase the likelihood of having offspring.

Despite these many examples of numerical competence in animals, this subject has not gotten many first-hand studies. "Many of these behavioral findings in the wild have usually been collected as by-products or accidental findings of other research questions," says Nieder.

Researchers do have some sense of the rules that govern numerical competence in animals, including that they count approximately rather than specifically and that two numbers need to be more different for them to tell them apart as those numbers get bigger -- and it does seem apparent that those abilities are adaptive. However, Nieder argues that more research needs to be done to fully understand the selective pressures and fitness payoffs of numerical competence.

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Bees can link symbols to numbers, study finds

Bees on honeycomb.

We've learned bees can understand zero and do basic math, and now a new study shows their tiny insect brains may be capable of connecting symbols to numbers.

Researchers have trained honeybees to match a character to a specific quantity, revealing they are able to learn that a symbol represents a numerical amount.

It's a finding that sheds new light on how numerical abilities may have evolved over millennia and even opens new possibilities for communication between humans and other species.

The discovery, from the same Australian-French team that found bees get the concept of zero and can do simple arithmetic, also points to new approaches for bio-inspired computing that can replicate the brain's highly efficient approach to processing.

The RMIT University-led study is published in the Proceedings of the Royal Society B.

Associate Professor Adrian Dyer said while humans were the only species to have developed systems to represent numbers, like the Arabic numerals we use each day, the research shows the concept can be grasped by brains far smaller than ours.

"We take it for granted once we've learned our numbers as children, but being able to recognise what '4' represents actually requires a sophisticated level of cognitive ability," Dyer said.

"Studies have shown primates and birds can also learn to link symbols with numbers, but this is the first time we've seen this in insects.

"Humans have over 86 billion neurons in our brains, bees have less than a million, and we're separated by over 600 million years of evolution.

"But if bees have the capacity to learn something as complex as a human-made symbolic language, this opens up exciting new pathways for future communication across species."

Mini brains, maximum potential: what the bees learned

Studies have shown that a number of non-human animals have been able to learn that symbols can represent numbers, including pigeons, parrots, chimpanzees and monkeys.

Some of their feats have been impressive -- chimpanzees were taught Arabic numbers and could order them correctly, while an African grey parrot called Alex was able to learn the names of numbers and could sum the quantities.

The new study for the first time shows that this complex cognitive capacity is not restricted to vertebrates.

The bee experiment was conducted by Dr Scarlett Howard, formerly a PhD researcher in the Bio Inspired Digital Sensing-Lab (BIDS-Lab) at RMIT and now a fellow at the Research Center on Animal Cognition, University of Toulouse III -- Paul Sabatier, CNRS.

In a Y-shaped maze, individual bees were trained to correctly match a character with a number of elements.

They were then tested on whether they could apply their new knowledge to match the character to various elements of the same quantity (in the same way that '2' can represent two bananas, two trees or two hats).

A second group was trained in the opposite approach, matching a number of elements with a character.

While both could grasp their specific training, the different groups were unable to reverse the association and work out what to do when tested with the opposite (character-to-number or number-to-character).

"This suggests that number processing and understanding of symbols happens in different regions in bee brains, similar to the way separate processing happens in the human brain," Howard said.

"Our results show honeybees are not at the same level as the animals that have been able to learn symbols as numbers and perform complex tasks.

"But the results have implications for what we know about learning, reversing tasks, and how the brain creates connections and associations between concepts.

"Discovering how such complex numerical skills can be grasped by miniature brains will help us understand how mathematical and cultural thinking evolved in humans, and possibly, other animals."

Studying insect brains offers intriguing possibilities for the future design of highly efficient computing systems, Dyer said.

"When we're looking for solutions to complex problems, we often find that nature has already done the job far more elegantly and efficiently," he said.

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Treats might mask animal intelligence

Rat with cheese.

Rewards are frequently used to promote learning, but rewards may actually mask true knowledge, finds a new Johns Hopkins University study with rodents and ferrets.

The findings, published May 14 in Nature Communications, show a distinction between knowledge and performance, and provide insight into how environment can affect the two.

"Most learning research focuses on how humans and other animals learn 'content' or knowledge. Here, we suggest that there are two parallel learning processes: one for content and one for context, or environment. If we can separate how these two pathways work, perhaps we can find ways to improve performance," says Kishore Kuchibhotla, an assistant professor in The Johns Hopkins University's department of psychological and brain sciences and the study's lead author.

While researchers have known that the presence of reinforcement, or reward, can change how animals behave, it's been unclear exactly how rewards affect learning versus performance.

An example of the difference between learning and performance, Kuchibhotla explains, is the difference between a student studying and knowing the answers at home, and a student demonstrating that knowledge on a test at school.

"What we know at any given time can be different than what we show; the ability to access that knowledge in the right environment is what we're interested in," he says.

To investigate what animals know in hopes of better understanding learning, Kuchibhotla and the research team trained mice, rats and ferrets on a series of tasks, and measured how accurately they performed the tasks with and without rewards.

For the first experiment, the team trained mice to lick for water through a lick tube after hearing one tone, and to not lick after hearing a different, unrewarded tone. It takes mice two weeks to learn this in the presence of the water reward. At a time point early in learning, around days 3-5, the mice performed the task at chance levels (about 50%) when the lick tube/reward was present. When the team removed the lick tube entirely on these early days, however, the mice performed the task at more than 90% accuracy. The mice, therefore, seemed to understand the task many days before they expressed knowledge in the presence of a reward.

To confirm this finding with other tasks and animals, the team also had mice press a lever for water when they heard a certain tone; prompted rats to look for food in a cup if they heard a tone, but not if a light appeared before the tone; had rats press a lever for sugar water when a light was presented before a tone; had rats push lever for sugar water when they heard a certain tone, and prompted ferrets to differentiate between two different sounds for water. In all experiments, the animals performed better when rewards weren't available.

"Rewards, it seems, help improve learning incrementally, but can mask the knowledge animals have actually attained, particularly early in learning," says Kuchibhotla. Furthermore, the finding that all animals' performance improved across the board without rewards, suggest that variability in learning rates may be due to differences in the animals' sensitivity to reward context rather than differences in intelligence.

The dissociation between learning and performance, the researchers suggest, may someday help us isolate the root causes of poor performance. While the study involved only rodents and ferrets, Kuchibhotla says it may be possible to someday help animals and humans alike better access content when they need it if the right mechanisms within the brain can be identified and manipulated.

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Orangutans make complex economic decisions about tool use

An adult male uses a stick tool.

Flexible tool use is closely associated to higher mental processes such as the ability to plan actions. Now a group of cognitive biologists and comparative psychologists from the University of Vienna, the University of St Andrews and the University of Veterinary Medicine Vienna that included Isabelle Laumer and Josep Call, has studied tool related decision-making in a non-human primate species -- the orangutan. They found that the apes carefully weighed their options: eat an immediately available food reward or wait and use a tool to obtain a better reward instead? To do so the apes considered the details such as differences in quality between the two food rewards and the functionality of the available tools in order to obtain a high quality food reward, even when multidimensional task components had to be assessed simultaneously.

Tool-use in animals is a rare and often quickly rated as intelligent due to its striking nature. For instance, antlions throw small pebbles at potential prey, archer fish down prey by spitting water at them, and sea otters use stones to crack open shells. Nevertheless, most types of tool use are quite inflexible, typically applied to one situation and tightly controlled by processes that are a part of the respective animal's inborn behavioural repertoire. In contrast, intelligent tool use requires the integration of multiple sources of information to flexibly adapt to quickly changing environmental conditions.

Orangutans share 97 percent of their DNA with us and are among the most intelligent and most endangered primates. They have human-like long-term memory, routinely use a variety of sophisticated tools in the wild and construct elaborate sleeping nests each night from foliage and branches. In their natural habitat, the evergreen rainforests of Borneo and Sumatra, orangutans have to consider several factors simultaneously, such as the predictability to find ripe fruits, the distance and reachability of food as well as the available tools to open extractable food sources. So far it was unknown how orangutans adapt their decisions when the use of a tool is involved and how many factors they can process at the same time in order to make profitable decisions.

Researchers from the University of Vienna, the University of Veterinary Medicine Vienna and the University of St Andrews investigated for the first time how orangutans adapt their decisions when the use of a tool is involved and how many factors they can process at the same time in order to make profitable decisions at the Wolfgang Koehler Primate Research Center in Leipzig.

The researchers used two different types of food items: Banana-pellets, which are the orangutans' most favourite food type, and apple pieces which they like but disregard if banana-pellets are available. They could extract these items from two different apparatuses: an apparatus required probing with a stick tool to obtain the food item while the other required dropping a ball inside it. Each apparatus could only be operated with the respective tool. During testing, orang-utans were confronted with either one or two baited apparatus/es and a choice between two items (usually a food item and a tool). Once the apes had picked one item the other was immediately removed.

Orangutans flexibly adapted their decisions to different conditions: "If the apple piece (likeable food) or the banana-pellet (favourite food) was out of immediate reach inside the apparatus and the choice was between an immediate banana-pellet and a tool, they chose the food over the tool, even when the tool was functional for the respective apparatus," explains Isabelle Laumer who conducted the experiment. "However, when the orangutans could choose between the apple-piece and a tool they chose the tool but only if it worked for the available apparatus: For example when the stick and the likeable food was available but the apes faced the ball-apparatus baited with the favourite banana-pellet, they chose the apple-piece over the non-functional tool. However when the stick-apparatus with the banana-pellet inside was available they chose the stick-tool over the immediate apple-piece," she further explains. "In a final task, that required the orangutans to simultaneously focus on the two apparatuses, one baited with the banana-pellet and the other with the apple and the orangutans had to choose between the two tools they were still able to make profitable decisions by choosing the tool that enabled them to operate the apparatus with the favorite food."

These results are similar to findings in Gofffin cockatoos that have been previously tested in the same task. "Similar to the apes, the cockatoos could overcome immediate impulses in favor of future gains even if this implied tool use. "The birds were confronted with the choice between a tool to retrieve an out-of-reach food item and an immediate reward. We found that they, similar to the apes, were highly sensible to the quality of the immediate relative to the out-of-reach reward at the same time as to whether the available tool would actually work with the task at hand," explains Alice Auersperg, the head of the Goffin Lab in Austria. She continues: "Again, this suggests that similar cognitive abilities can evolve independently in distantly related species."Nevertheless, the cockatoos did reach their limit at the very last task in which both apparatuses baited with both possible food qualities and both tools were available at the same time."

"Optimality models suggest that orangutans should flexibly adapt their foraging decisions depending on the availability of high nutritional food sources, such as fruits," says Josep Call from the University of St Andrews. "Our study shows that orangutans can simultaneously consider multi-dimensional task components in order to maximize their gains and it is very likely that we haven´t even reached the full extent of their information processing capabilities."

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Fish Appear to Recognize Themselves in the Mirror

A cleaner wrasse interacts with its reflection in a mirror placed on the outside of the aquarium glass. Note that the mirror itself cannot be seen in this photo because the aquarium glass itself becomes reflective at the viewing angle of the camera, according to Snell's law. This is not the case for the fish itself, which sees the aquarium glass as transparent because of its direct viewing angle.

A species of fish, the cleaner wrasse (Labroides dimidiatus), responds to its reflection and attempts to remove marks on its body during the mirror test -- a method held as the gold standard for determining if animals are self-aware. The finding, publishing on February 7 in the open-access journal PLOS Biology, suggests that fish might possess far higher cognitive powers than previously thought, and ignites a high-stakes debate over how we assess the intelligence of animals that are so unlike ourselves.

The study's researchers from the Max Planck Institute for Ornithology (MPIO) and Osaka City University (OCU), say that their results provide clear evidence of behaviours that appear to pass through all phases of the mirror test, but that the interpretation of what these mean is less clear: Does a 'pass' mark in the mirror test demonstrate that fish possess self-awareness -- a cognitive trait thought only to be present in primates and some other mammals? Or can the mirror test be solved by very different cognitive processes than previously thought?

"The behaviours we observe leave little doubt that this fish behaviourally fulfils all criteria of the mirror test as originally laid out. What is less clear is whether these behaviours should be considered as evidence that fish are self-aware -- even though in the past these same behaviours have been interpreted as self-awareness in so many other animals," says Dr Alex Jordan, senior author on the study.

The ability to perceive and recognise a reflected mirror image as self (mirror self-recognition) is considered a hallmark of cognition across species. To test for this phenomenon in fish, the researchers applied the classic 'mark' test to the cleaner wrasse (Labroides dimidiatus) -- a marine fish best known for its behaviour of "cleaning" external parasites from client fish -- by placing a coloured mark on fish in a location that can only be seen in a mirror reflection. In order to gain a 'pass', the test requires that the animal must touch or investigate the mark, demonstrating that it perceives the reflected image as itself. This is clearly a challenge for animals such as fish that lack limbs and hands.

The researchers observed that fish attempted to remove the marks by scraping their bodies on hard surfaces after viewing themselves in the mirror. Fish never attempted to remove transparent marks in the presence of a mirror, or coloured marks when no mirror was present -- suggesting that marked fish were responding to the visual cue of seeing the mark on themselves in the mirror. Further, unmarked fish did not attempt to remove marks from themselves when interacting with a marked fish across a clear divider, nor did they attempt to remove marks placed on the mirror itself -- suggesting that fish were not innately reacting to a mark resembling an ectoparasite anywhere in the environment, for instance due to hard-wired feeding responses.

Dr Jordan acknowledges the controversial nature of the study, saying: "Depending on your position, you might reject the interpretation that these behaviours in a fish satisfy passing the test at all. But on what objective basis can you do this when the behaviours they show are so functionally similar to those of other species that have passed the test?"

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Bees can do basic arithmetic

Honeybee.

Researchers have found bees can do basic mathematics, in a discovery that expands our understanding of the relationship between brain size and brain power.

Building on their finding that honeybees can understand the concept of zero, Australian and French researchers set out to test whether bees could perform arithmetic operations like addition and subtraction.

Solving maths problems requires a sophisticated level of cognition, involving the complex mental management of numbers, long-term rules and short term working memory.

The revelation that even the miniature brain of a honeybee can grasp basic mathematical operations has implications for the future development of Artificial Intelligence, particularly in improving rapid learning.

Led by researchers from RMIT University in Melbourne, Australia, the new study showed bees can be taught to recognise colours as symbolic representations for addition and subtraction, and that they can use this information to solve arithmetic problems.

RMIT's Associate Professor Adrian Dyer said numerical operations like addition and subtraction are complex because they require two levels of processing.

"You need to be able to hold the rules around adding and subtracting in your long-term memory, while mentally manipulating a set of given numbers in your short-term memory," Dyer said.

"On top of this, our bees also used their short-term memories to solve arithmetic problems, as they learned to recognise plus or minus as abstract concepts rather than being given visual aids.

"Our findings suggest that advanced numerical cognition may be found much more widely in nature among non-human animals than previously suspected.

"If maths doesn't require a massive brain, there might also be new ways for us to incorporate interactions of both long-term rules and working memory into designs to improve rapid AI learning of new problems."

There is considerable debate around whether animals know or can learn complex number skills.

Many species can understand the difference between quantities and use this to forage, make decisions and solve problems. But numerical cognition, such as exact number and arithmetic operations, requires a more sophisticated level of processing.

Previous studies have shown some primates, birds, babies and even spiders can add and/or subtract. The new research, published in Science Advances, adds bees to that list.

A school for bees? How the honeybees were trained

The experiment, conducted by PhD researcher Scarlett Howard in the Bio Inspired Digital Sensing-Lab (BIDS-Lab) at RMIT, involved training individual honeybees to visit a Y-shaped maze.

The bees received a reward of sugar water when they made a correct choice in the maze, and received a bitter-tasting quinine solution if the choice was incorrect.

Honeybees will go back to a place if the location provides a good source of food, so the bees returned repeatedly to the experimental set-up to collect nutrition and continue learning.

When a bee flew into the entrance of the maze they would see a set of elements, between 1 to 5 shapes.

The shapes were either blue, which meant the bee had to add, or yellow, which meant the bee had to subtract.

After viewing the initial number, the bee would fly through a hole into a decision chamber where it could choose to fly to the left or right side of the maze.

One side had an incorrect solution to the problem and the other side had the correct solution of either plus or minus one. The correct answer was changed randomly throughout the experiment to avoid bees learning to visit just one side of the maze.

At the beginning of the experiment, bees made random choices until they could work out how to solve the problem. Eventually, over 100 learning trials that took 4 to 7 hours, bees learned that blue meant +1, while yellow meant -1. The bees could then apply the rules to new numbers.

Scarlett Howard said the ability to do basic maths has been vital in the flourishing of human societies historically, with evidence that the Egyptians and Babylonians used arithmetic around 2000BC.

"These days, we learn as children that a plus symbol means you need to add two or more quantities, while a minus symbol means you subtract," she said.

Read more at Science Daily

Bees can count with small number of nerve cells in their brains, research suggests

A bumblebee choosing between two patterns containing different numbers of yellow circles.

Bees can solve seemingly clever counting tasks with very small numbers of nerve cells in their brains, according to researchers at Queen Mary University of London.

In order to understand how bees count, the researchers simulated a very simple miniature 'brain' on a computer with just four nerve cells -- far fewer than a real bee has.

The 'brain' could easily count small quantities of items when inspecting one item closely and then inspecting the next item closely and so on, which is the same way bees count. This differs from humans who glance at all the items and count them together.

In this study, published in the journal iScience, the researchers propose that this clever behaviour makes the complex task of counting much easier, allowing bees to display impressive cognitive abilities with minimal brainpower.

Previous studies have shown bees can count up to four or five items, can choose the smaller or the larger number from a group and even choose 'zero' against other numbers when trained to choose 'less'.

They might have achieved this not by understanding numerical concepts, but by using specific flight movements to closely inspect items which then shape their visual input and simplifies the task to the point where it requires minimal brainpower.

This finding demonstrates that the intelligence of bees, and potentially other animals, can be mediated by very small nerve cells numbers, as long as these are wired together in the right way.

The study could also have implications for artificial intelligence because efficient autonomous robots will need to rely on robust, computationally inexpensive algorithms, and could benefit from employing insect-inspired scanning behaviours.

Lead author Dr Vera Vasas, from Queen Mary University of London, said: "Our model shows that even though counting is generally thought to require high intelligence and large brains, it can be easily done with the smallest of nerve cell circuits connected in the right manner. We suggest that using specific flight movements to scan targets, rather than numerical concepts, explains the bees' ability to count. This scanning streamlines the visual input and means a task like counting requires little brainpower.

"Careful examination of the actual inspection strategies used by animals might reveal that they often employ active scanning behaviours as shortcuts to simplify complex visual pattern discrimination tasks. Hopefully, our work will inspire others to look more closely not just at what cognitive tasks animals can solve, but also at how they are solving them."

Brain size matters a lot when it comes to bees. They have only one million nerve cells in total, so they have precious little brainpower, and must implement very efficient computational algorithms to solve tasks. In comparison, humans have 86 billion nerve cells which are responsible for receiving information and sending commands.

To model the input to the brain, the authors analysed the point of view of a bee as it flies close to the countable objects and inspects them one-by-one.

The results showed the simulated brain was able to make reliable estimates on the number of items on display when provided with the actual visual input that the bee is receiving while carrying out the task.

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Orangutans spontaneously bend straight wires into hooks to fish for food

Male orangutan using a stick tool.

The bending of a hook into wire to fish for the handle of a basket is surprisingly challenging for young children under eight years of age. Now cognitive biologists and comparative psychologists from the University of Vienna, the University of St Andrews and the University of Veterinary Medicine Vienna working with Isabelle Laumer and Alice Auersperg studied hook tool making for the first time in a non-human primate species -- the orangutan. To the researchers' surprise the apes spontaneously manufactured hook tools out of straight wire within the very first trial and in a second task unbent curved wire to make a straight tool.

Human children are already proficient tool-users and tool-makers from an early age on. Nevertheless, when confronted with a task, which required them to innovate a hooked tool out of a straight piece of wire in order to retrieve a basket from the bottom of a vertical tube, the job proved more challenging for children than one might think: Three to five-year-old children rarely succeed and even at the age of seven less than half of them were able to solve the task. Only at the age of eight the majority of children was able to innovate a hook-tool. Interestingly children of all tested age classes succeeded when given demonstrations on how to bend a hook and use it. Thus, although young children apparently understand what kind of tool is required and are skilled enough to make a functional tool, there seems to be a cognitive obstacle in innovating one.

Cognitive biologists and comparative psychologists have now tested for the first time a primate species in the hook-bending task. "We confronted the orangutans with a vertical tube containing a reward basket with a handle and a straight piece of wire. In a second task with a horizontal tube containing a reward at its centre and a piece of wire that was bent at 90°," explains Isabelle Laumer who conducted the study at the Zoo Leipzig in Germany. "Retrieving the reward from the vertical tube thus required the orangutans to bent a hook into the wire to fish the basket out of the tube. The horizontal tube in turn required the apes to unbent the bent piece of wire in order to make it long enough to push the food out of the tube."

Several orangutans mastered the hook bending task and the unbending task. Two orangutans even solved both tasks within the first minutes of the very first trial. "The orangutans mostly bent the hooks directly with their teeth and mouth while keeping the rest of the tool straight. Thereafter they immediately inserted it in correct orientation, hooked the handle and pulled the basket up," she further explains.

Orangutans share 97% of their DNA with us and are among the most intelligent primates. They have human-like long-term memory, routinely use a variety of sophisticated tools in the wild and construct elaborate sleeping nests each night from foliage and branches. Today orangutans can only be found in the rainforests of Sumatra and Borneo. Like all four great ape species, orangutans are listed as critically endangered (IUCN, Red List). "Habitat loss due to extensive palm-oil production, illegal wildlife trade and poaching are the major threats. Palm oil is the most widely used vegetable oil in the world. As long as there is a demand for palm oil and consumers keep buying products that contain palm oil, the palm industry thrives. According to a 2007 survey by the United Nations Environment Program (UNEP) orangutans will be extinct in the wild within two decades if current deforestation trends continue," says Isabelle Laumer.

"The hook-bending task has become a benchmark paradim to test tool innovation abilities in comparative psychology," says Alice Auersperg from the University of Veterinary Medicine in Vienna. "Considering the speed of their hook innovation, it seems that they actively invented a solution to this problem rather than applying routined behaviours."

"Finding this capacity in one of our closest relatives is astonishing. In human evolution hook tools appear relatively late. Fish hooks and harpoon-like, curved objects date back only approximately 16,000- 60,000 years. Although New Caledonian crows use hooks with regularity, there are a few observations of wild apes, such as chimpanzees and orangutans, that use previously detached branches to catch and retrieve out-of-reach branches for locomotion in the canopy. This branch-hauling tools might represents one of the earliest and simplest raking tools used and made by great apes and our ancestors," says Josep Call of the University of St Andrews.

Read more at Science Daily

Goffin's cockatoos can create and manipulate novel tools

A Goffin cockatoo tears off a strip of cardboard.

Goffin's cockatoos can tear cardboard into long strips as tools to reach food -- but fail to adjust strip width to fit through narrow openings, according to a study published November 7, 2018 in the open-access journal PLOS ONE by A.M.I. Auersperg from the Medical University of Vienna, Austria, and colleagues.

The Goffin's cockatoo (Cacatua goffiniana) is a type of parrot. Captive Goffins are capable of inventing and manipulating tools, even though they aren't known to use tools habitually. The authors of the present study investigated two questions: do Goffins adjust tool properties to save effort, and if so, how accurately can they adjust tool dimensions for the task? The authors supplied six adult cockatoos with large cardboard sheets to tear into strips as tools for the testing apparatus: a food platform with a food reward set at varying distances (4-16cm) behind a small opening which also varied in width (1-2cm).

They found that the Goffins were capable of adjusting the length of their cardboard strip tools to account for variations in food distance, making shorter tools when the reward was closer than when it was set farther away. In every case, if a first-attempt tool was too short, the second-attempt tool would be significantly longer. On average, all six birds made significantly longer tools than were required to reach the reward in all test conditions, with the birds tending to make increasingly long tools as the study progressed -- perhaps as a risk-avoidance strategy.

However, only one bird was able to make a sufficiently-narrow tool to successfully reach the food reward when the opening was at its narrowest. The authors hypothesize that the shearing technique the birds use to tear the cardboard limits the narrowness of the resulting strips. The authors suggest that future studies provide less restrictive materials to assess whether Goffins are cognitively capable of adjusting tool width in this situation.

Alice Auersperg adds: "The way they inserted and discarded manufactured pieces of specific lengths differently depending on condition suggests that the cockatoos could indeed adjust their tool making behavior in the predicted direction but with some limits in accuracy."

From Science Daily

Birds startled by moving sticks

The objects used in this research.

Do animals -- like humans -- divide the world into things that move and things that don't? Are they surprised if an apparently inanimate object jumps to life?

Yes -- according to scientists at the universities of Exeter and Cambridge.

The researchers tested how jackdaws responded to moving birds, moving snakes and moving sticks -- and found they were most cautious of the moving sticks.

The study, using remote-controlled objects placed in jackdaws' nests, will help scientists understand how birds perceive potential threats.

"Although as humans we see the divide between animate an inanimate objects as an intuitive one, we've had very little evidence that wild animals also see the world this way," said lead author Dr Alison Greggor, formerly of the University of Cambridge and now at the San Diego Zoo Institute for Conservation Research.

"Laboratory studies have shown that human infants and a few other species discriminate between animate and inanimate objects.

"This ability is assumed to have evolved to support social interactions, but its role for wild animals has never been examined.

"Our work extends the potential function of this ability beyond the social realm. It might therefore be a more common ability than previously thought."

By placing remote-controlled objects in jackdaws' nests, the researchers tested how the birds assessed possible threats to their offspring.

Jackdaws were startled by any movement, producing alarm calls, but they delayed longest in entering their nest box after encountering an "inanimate" object that moved (ie the remote controlled stick).

This suggests they recognised the movement as unexpected and delayed entering the nest in order to gather more information about the situation.

Dr Alex Thornton, of the Centre for Ecology and Conversation on the University of Exeter's Penryn Campus in Cornwall, added: "There is still a great deal we do not understand about some of our common bird species.

Read more at Science Daily

New Caledonian crows can create compound tools

This is a new Caledonian crow with a stick tool.

An international team of scientists from the Max Planck Institute for Ornithology in Seewiesen, Germany, and the University of Oxford have revealed that New Caledonian crows are able to create tools by combining two or more otherwise non-functional elements, an ability so far observed only in humans and great apes.

The new study shows that these birds can create long-reaching tools out of short combinable parts -- an astonishing mental feat. Assemblage of different components into novel functional and manoeuvrable tools has, until now, only been observed in apes, and anthropologists regard early human compound tool manufacture as a significant step in brain evolution. Children take several years before creating novel tools, probably because it requires anticipating properties of yet unseen objects. Such anticipation, or planning, is usually interpreted as involving creative mental modelling and executive functions.

The study demonstrates that this species of crow possess highly flexible abilities that allow them to solve complex problems involving anticipation of the properties of objects they have never seen. 'The finding is remarkable because the crows received no assistance or training in making these combinations, they figured it out by themselves,' says Auguste von Bayern, first author of the study from the Max-Planck-Institute for Ornithology and University of Oxford.

Famous for the use of tools

The New Caledonia crows (Corvus moneduloides) from the South Pacific are of the same species as Betty, who became famous in 2002 as the first animal shown to be able to create a hooked tool by bending a pliable material. Researchers had already been able to show how this remarkable species were able to use and make tools in the wild and in captivity, but they had never previously been seen to combine more than one piece to make a tool.

Alex Kacelnik from the University of Oxford says: 'The results corroborate that these crows possess highly flexible abilities that allow them to solve novel problems rapidly, but do not show how they do it. It is possible that they use some form of virtual simulation of the problem, as if different potential actions were played in their brains until they figure out a viable solution, and then do it. Similar processes are being modelled on artificial intelligences and implemented in physical robots, as a way to better understand the animals and to discover ways to build machines able to reach autonomous creative solutions to novel problems.'

The researchers presented eight New Caledonian crows with a puzzle box they had never encountered before, containing a small food container behind a door that left a narrow gap along the bottom. Initially, the scientists left some sufficiently long sticks scattered around, and all the birds rapidly picked one of them, inserted it through the front gap, and pushed the food to an opening on the side of the box. All eight birds did this without any difficulty. In the next steps, the scientists left the food deep inside the box but provided only short pieces, too short to reach the food. These short pieces could potentially be combined with each other, as some were hollow and others could fit inside them.

Without any help or demonstration, four of the crows partially inserted one piece into another and used the resulting longer compound pole to reach and extract the food. At the end of the five-step investigation, the scientists made the task more difficult by supplying even shorter combinable parts, and found that one particular bird, 'Mango', was able to make compound tools out of three and even four parts.

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Scientists chase mystery of how dogs process words

Eddie, one of the dogs that participated in the study, poses in the fMRI scanner with two of the toys used in the experiments, "Monkey" and "Piggy."

When some dogs hear their owners say "squirrel," they perk up, become agitated. They may even run to a window and look out of it. But what does the word mean to the dog? Does it mean, "Pay attention, something is happening?" Or does the dog actually picture a small, bushy-tailed rodent in its mind?

Frontiers in Neuroscience published one of the first studies using brain imaging to probe how our canine companions process words they have been taught to associate with objects, conducted by scientists at Emory University. The results suggest that dogs have at least a rudimentary neural representation of meaning for words they have been taught, differentiating words they have heard before from those they have not.

"Many dog owners think that their dogs know what some words mean, but there really isn't much scientific evidence to support that," says Ashley Prichard, a PhD candidate in Emory's Department of Psychology and first author of the study. "We wanted to get data from the dogs themselves -- not just owner reports."

"We know that dogs have the capacity to process at least some aspects of human language since they can learn to follow verbal commands," adds Emory neuroscientist Gregory Berns, senior author of the study. "Previous research, however, suggests dogs may rely on many other cues to follow a verbal command, such as gaze, gestures and even emotional expressions from their owners."

The Emory researchers focused on questions surrounding the brain mechanisms dogs use to differentiate between words, or even what constitutes a word to a dog.

Berns is founder of the Dog Project, which is researching evolutionary questions surrounding man's best, and oldest friend. The project was the first to train dogs to voluntarily enter a functional magnetic resonance imaging (fMRI) scanner and remain motionless during scanning, without restraint or sedation. Studies by the Dog Project have furthered understanding of dogs' neural response to expected reward, identified specialized areas in the dog brain for processing faces, demonstrated olfactory responses to human and dog odors, and linked prefrontal function to inhibitory control.

For the current study, 12 dogs of varying breeds were trained for months by their owners to retrieve two different objects, based on the objects' names. Each dog's pair of objects consisted of one with a soft texture, such as a stuffed animal, and another of a different texture, such as rubber, to facilitate discrimination. Training consisted of instructing the dogs to fetch one of the objects and then rewarding them with food or praise. Training was considered complete when a dog showed that it could discriminate between the two objects by consistently fetching the one requested by the owner when presented with both of the objects.

During one experiment, the trained dog lay in the fMRI scanner while the dog's owner stood directly in front of the dog at the opening of the machine and said the names of the dog's toys at set intervals, then showed the dog the corresponding toys.

Eddie, a golden retriever-Labrador mix, for instance, heard his owner say the words "Piggy" or "Monkey," then his owner held up the matching toy. As a control, the owner then spoke gibberish words, such as "bobbu" and "bodmick," then held up novel objects like a hat or a doll.

The results showed greater activation in auditory regions of the brain to the novel pseudowords relative to the trained words.

"We expected to see that dogs neurally discriminate between words that they know and words that they don't," Prichard says. "What's surprising is that the result is opposite to that of research on humans -- people typically show greater neural activation for known words than novel words."

The researchers hypothesize that the dogs may show greater neural activation to a novel word because they sense their owners want them to understand what they are saying, and they are trying to do so. "Dogs ultimately want to please their owners, and perhaps also receive praise or food," Berns says.

Half of the dogs in the experiment showed the increased activation for the novel words in their parietotemporal cortex, an area of the brain that the researchers believe may be analogous to the angular gyrus in humans, where lexical differences are processed.

The other half of the dogs, however, showed heightened activity to novel words in other brain regions, including the other parts of the left temporal cortex and amygdala, caudate nucleus, and the thalamus.

These differences may be related to a limitation of the study -- the varying range in breeds and sizes of the dogs, as well as possible variations in their cognitive abilities. A major challenge in mapping the cognitive processes of the canine brain, the researchers acknowledge, is the variety of shapes and sizes of dogs' brains across breeds.

"Dogs may have varying capacity and motivation for learning and understanding human words," Berns says, "but they appear to have a neural representation for the meaning of words they have been taught, beyond just a low-level Pavlovian response."

This conclusion does not mean that spoken words are the most effective way for an owner to communicate with a dog. In fact, other research also led by Prichard and Berns and recently published in Scientific Reports, showed that the neural reward system of dogs is more attuned to visual and to scent cues than to verbal ones.

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Dog intelligence 'not exceptional'

Dogs' intelligence has been brought into question.

People who think dogs are exceptionally intelligent are barking up the wrong tree, new research shows.

Scientists reviewed evidence that compared the brain power of dogs with other domestic animals, other social hunters and other carnivorans (an order including animals such as dogs, wolves, bears, lions and hyenas).

The researchers, from the University of Exeter and Canterbury Christ Church University, found the cognitive abilities of dogs were at least matched by several species in each of these groups.

The study examined more than 300 papers on the intelligence of dogs and other animals, and found several cases of "over interpretation" in favour of dogs' abilities.

"During our work it seemed to us that many studies in dog cognition research set out to 'prove' how clever dogs are," said Professor Stephen Lea, of the University of Exeter.

"They are often compared to chimpanzees and whenever dogs 'win', this gets added to their reputation as something exceptional.

"Yet in each and every case we found other valid comparison species that do at least as well as dogs do in those tasks."

The review focussed on sensory cognition, physical cognition, spatial cognition, social cognition and self-awareness.

"Taking all three groups (domestic animals, social hunters and carnivorans) into account, dog cognition does not look exceptional," said Dr Britta Osthaus, of Canterbury Christ Church University.

"We are doing dogs no favour by expecting too much of them. Dogs are dogs, and we need to take their needs and true abilities into account when considering how we treat them."

From Science Daily

Earth's oldest animals formed complex ecological communities

These are Ediacara biota fossils found during Darroch's latest research in Namibia.

A new analysis is shedding light on Earth's first macroscopic animals: the 570-million-year-old, enigmatic Ediacara biota.

Ediacaran fossils have a slightly bizarre appearance not shared by any modern animal groups. For decades, researchers believed these enigmatic fossils were ecologically simple. However, borrowing a method from modern ecology -- fitting species to relative abundance distributions -- Vanderbilt University paleontologist Simon A.F. Darroch and his team learned that these organisms were more like modern animals than once thought.

The analyses showed that a majority of fossil assemblages bear the hallmarks of being ecologically complex, and Ediacara biota were forming complex communities tens of millions of years before the Cambrian explosion. The creatures lived partially submerged in what was once the ocean floor, some of them suspension feeding, others filter feeding, still others passively absorbing nutrition. A few were even mobile.

Complex communities are ones that comprise species competing for numerous different resources or species that create niches for others (as in many modern-day ecosystems). The team found that the signature of complex communities extends all the way back to the oldest Ediacaran fossils. In other words, as soon as macroscopic life evolved, it began forming diverse ecological communities not unlike those in the present day.

"The main impact of our work was testing between the simple and complex models for Ediacaran ecosystems," said Darroch, an assistant professor in Vanderbilt's Earth and Environmental Sciences Department.

"Supporting a simple model would suggest that these mysterious organisms were universally primitive, sharing the same basic ecology and all competing for the same resources," he said. "Support for the complex model would instead suggest that they likely competed for a variety of different resources, just like modern animals. Our analyses support the complex model, illustrating that -- even though they may look bizarre -- these mysterious fossils may have far more in common with modern animals than we thought."

Their paper, "High ecological complexity in benthic Ediacaran communities," is available online today in Nature Ecology & Evolution.

The team first compiled all Ediacaran fossil data from the published literature then added a dataset collected during fieldwork in southern Namibia. These Namibian fossils are the some of the youngest from anywhere in the world and record communities that were living immediately prior to the onset of the Cambrian explosion.

The fossils formed one of the few simple communities in the analysis, suggesting that these organisms were ecologically stressed. That lends support to the idea that the Ediacara biota were gradually going extinct in the run-up to the Cambrian explosion. Although it's an exciting idea, Darroch said, it's only one data point and will need much more research to prove.

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How birds learn

Zebra finch.

Children are constantly learning new things, but whether they find it easy or hard to generalise what they have learned and apply it to new situations can depend on how they learned it. It is much the same for songbirds. In their first few months of life, they too must learn a great deal; for example, the characteristic song of their species. And like people, birds also learn in different ways. How these methods impact the ability to generalise was the subject of a study on zebra finches, conducted by a research team led by Richard Hahnloser, Professor at ETH Zurich and the University of Zurich.

In their experiments, the researchers were able to show that zebra finches can learn by observing fellow members of their species. The birds had to learn through trial and error to discriminate between two classes of birdsong, one long and one short. Without any special preparation, the median number of repetitions it took for the birds to master the task was 4,700. But if the finches were able to observe other finches as they learned this task, then it took them just 900 repetitions. In this experimental set up and for statistical reasons, 800 repetitions are required in order to evaluate the animals' performance. This means that the observing birds mastered the task almost from the very beginning.

Better generalisation

In the next phase of the experiment, the researchers tested how well the zebra finches could solve a second, similar task, in which the birds had to distinguish between varying lengths of a different sample of birdsongs. This revealed that birds that learned the first task using trial and error from the outset could solve the second task practically right away: It took them a median of just 800 attempts. By contrast, birds that learned the first task primarily through observation needed a median value of 3,600 attempts.

"These results indicate that in zebra finches, learning by trial and error is the more robust method," summarises Hahnloser, continuing, "Birds that learned a perceptual skill through trial and error were better able to generalise and adapt that skill to new situations than those that learned it through observation."

Both learning methods have their advantages

Gagan Narula, a postdoc in Hahnloser's group and lead author of the study, points to parallels with how children and youths learn: "Active learning, which focuses on experimentation and trial and error, is becoming more and more prevalent in schools. In secondary schools, even maths is now being taught with the help of experiments."

Still, "both methods have their advantages," Hahnloser says, "but learning through observation is faster." He notes that the Swiss education system deliberately incorporates both learning methods: lectures and observation on the one hand, and experiments, exercises and homework on the other.

Differing degrees of brain involvement

Neural computer models assisted the scientists in interpreting their findings. From these model calculations, the researchers surmise that although the act of observation involves many synapses between neurons in a finch brain, these are relatively weak. In contrast, trial-and-error learning involves a smaller number of synapses, but they are much stronger, leading to an enhanced ability to generalise. Hahnloser explains: "When observing, the birds may focus on a large number of song details, many of which are irrelevant for solving the problem at hand. In the trial-and-error case, they remember fewer details but focus on the most prominent aspects of the song, such as its duration."

Whether different learning methods affect the brains of children and teenagers in the same way is still to be investigated. "In the past, research on zebra finches has repeatedly provided important clues and hypotheses for investigating neurobiological processes, in particular in relation to vocal learning," says Hahnloser. "Our latest findings in finches also lead to hypotheses that could be studied in humans to better understand social learning processes."

The experiment

For the experiment, the scientists used two adjacent birdcages separated by a partition, with a zebra finch in each cage. One of the finches had to use trial and error to learn to discriminate between two classes of birdsong. The other bird observed the learning process.

Each of the birds could see the other only by sitting on a particular perch in the cage next to a window in the partition. Because zebra finches are social animals, they were naturally drawn to this particular perch.

If the "experimenter" finch flew to that perch, it would hear one of ten variations of a zebra finch song. The samples had minimal differences in length, which was the defining property for splitting the song samples into two classes: Class A contained the five shorter song samples (lasting 0.9 to 1.0 seconds), and Class B had the five longer ones (1.03 to 1.13 seconds). One second after a sample from Class B was played, the team administered an air-puff to the bird.

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Neuroscientists uncover secret to intelligence in parrots

Not-so-bird brain: Neuroscientists discover the mechanism responsible for cognition in intelligent birds, like this parrot.

University of Alberta neuroscientists have identified the neural circuit that may underlay intelligence in birds, according to a new study. The discovery is an example of convergent evolution between the brains of birds and primates, with the potential to provide insight into the neural basis of human intelligence.

"An area of the brain that plays a major role in primate intelligence is called the pontine nuclei," explained Cristian Gutierrez-Ibanez, postdoctoral fellow in the Department of Psychology. "This structure transfers information between the two largest areas of the brain, the cortex and cerebellum, which allows for higher-order processing and more sophisticated behaviour. In humans and primates, the pontine nuclei are large compared to other mammals. This makes sense given our cognitive abilities."

Birds have very small pontine nuclei. Instead, they have a similar structure called the medial spiriform nucleus (SpM) that has similar connectivity. Located in a different part of the brain, the SpM does the same thing as the pontine nuclei, circulating information between the cortex and the cerebellum. "This loop between the cortex and the cerebellum is important for the planning and execution of sophisticated behaviours," said Doug Wylie, professor of psychology and co-author on the new study.

Not-so-bird brain

Using samples from 98 birds from the largest collection of bird brains in the world, including everything from chickens and waterfowl to parrots and owls, the scientists studied the brains of birds, comparing the relative size of the SpM to the rest of the brain. They determined that parrots have a SpM that is much larger than that of other birds.

"The SpM is very large in parrots. It's actually two to five times larger in parrots than in other birds, like chickens," said Gutierrez. "Independently, parrots have evolved an enlarged area that connects the cortex and the cerebellum, similar to primates. This is another fascinating example of convergence between parrots and primates. It starts with sophisticated behaviours, like tool use and self-awareness, and can also be seen in the brain. The more we look at the brains, the more similarities we see."

Next, the research team hopes to study the SpM in parrots more closely, to understand what types of information go there and why.

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How do horses read human emotional cues?

Several horses on a farm visited by Dr. Ayaka Takimoto.

Scientists demonstrated for the first time that horses integrate human facial expressions and voice tones to perceive human emotion, regardless of whether the person is familiar or not.

Recent studies showed the herd-forming animal possesses high communication capabilities, and can read the emotions of their peers through facial expressions and contact calls, or whinnies. Horses have long been used as a working animal and also as a companion animal in sports and leisure, establishing close relationships with humans just like dogs do with people.

Dogs are known to relate human facial expressions and voices to perceive human emotions, but little has been known as to whether horses can do the same.

In the present study to be published in Scientific Reports, Associate Professor Ayaka Takimoto of Hokkaido University, graduate student Kosuke Nakamura of The University of Tokyo, and former Professor Toshikazu Hasegawa of The University of Tokyo, used the expectancy violation method to investigate whether horses cross-modally perceive human emotion by integrating facial expression and voice tone. They also tested whether the familiarity between the horse and the person affected the horse's perception.

The expectancy violation method has been used to study infant cognitive development. Horses were shown a picture of a happy facial expression or an angry facial expression on a screen, and they then heard a pre-recorded human voice -- praising or scolding -- from a speaker behind the screen. Horses received both the congruent condition, in which the emotional values of facial expression and voice tone were matched, and the incongruent condition, in which they were not.

Results of the experiment showed that horses responded to voices 1.6 to 2.0 times faster in the incongruent condition than in the congruent condition regardless of familiarity of the person. In addition, the horses looked to the speaker 1.4 times longer in the incongruent condition than in the congruent condition when the person was familiar. These results suggest that horses integrate human facial expressions and voice tones to perceive human emotions, therefore an expectancy violation occurred when horses heard a human voice whose emotional value was not congruent with the human facial expression.

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Brain genes related to innovation revealed in birds

This is a Barbados bullfinch innovation in the wild: opening sugar packets.

Wild birds that are more clever than others at foraging for food have different levels of a neurotransmitter receptor that has been linked with intelligence in humans, according to a study led by McGill University researchers. The findings could provide insight into the evolutionary mechanisms affecting cognitive traits in a range of animals.

The study, published in Science Advances, was conducted by McGill biologists Jean-Nicolas Audet and Louis Lefebvre, in collaboration with researchers from Duke and Harvard universities.

Barbados birds

The researchers caught bullfinches and black-faced grassquits near McGill's Bellairs Research Institute in Barbados. Bullfinches are bold, opportunistic and innovative, while grassquits are shy and conservative. They are each other's closest relative in Barbados and are cousins of Darwin's finches from the Galápagos islands.

In captivity, the problem-solving skills of the two species differed considerably in lab tests. Most of the bullfinches quickly figured out how to lift the lid off a jar of food, for example, while all the grassquits were stumped by the challenge. These performances were in line with the differences in the birds' innovativeness in the wild -- a trait that can help animals survive in changing environments.

New tools for the study of wild behavior

The researchers then compared the expression of all genes in six parts of the brain of the two bird species using state-of-the-art molecular techniques, including next-generation sequencing -- the first time these tools have been used to find brain properties related to innovation and problem-solving in wild birds.

A family of genes stood out: glutamate neurotransmitter receptors, especially in the part of the bird brain that corresponds to humans' prefrontal cortex. Glutamate receptors are known to be involved in a variety of cognitive traits in humans and other mammals. In particular a receptor known as GRIN2B, when boosted in transgenic mice, makes them better learners. Levels of that receptor were higher in the Barbados bullfinch than in the grassquit, the researchers found.

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How a fish species in Lake Tanganyika works together to secure additional food sources

These are helpers of Neolamprologus obscurus in their nest.

Cooperative behaviour to acquire food resources has been observed in hunting carnivores and web-building social spiders. Now researchers have found comparable behaviours in a fish species. A tiny striped fish called Neolamprologus obscurus only found in Lake Tanganyika in Zambia excavates stones to create shelter and increase the abundance of food for all fish in the group. Led by Hirokazu Tanaka of the University of Bern in Switzerland and the Osaka City University in Japan, this study is the first to document how team work in fish helps them to acquire more food. The research is published in Springer's journal Behavioral Ecology and Sociobiology.

Neolamprologus obscurus is a highly sociable species of cichlid found only in the southern reaches of Lake Tanyanika. These zebra-striped fish feed mainly on shrimp and other invertebrates found along the bottom of the lake. At night, shrimp move into the water column, but by dawn they sink back to the lake bottom to hide in crevices and holes, including the shelters that the fish have dug out under stones. Such excavation work is always done as a group, as is subsequent maintenance efforts. Breeding fish seldom leave these safe havens and are supported by up to ten helpers from their family group. The helpers protect the brood, and constantly remove sand and debris that fall into the cavities.

"The function of these excavated cavities is much like that of the webs of social spiders, which live in groups and share the trapped prey among group members," explains Tanaka.

In this study, Tanaka and his colleagues wanted to find out if the size of the cavities at the bottom of the lake relate to the abundance of food available in the area, and if the presence of helpers influences the size. Through hours of scuba diving in Lake Tanyanika, the researchers created artificial cavities and examined the stomach contents of some of the fish. In another experiment, the researchers removed helpers that were assisting breeding fish. Within a week, enough sand had fallen into the cavities to decidedly shrink these spaces. This effect was augmented when the helpers removed were big.

One of the key findings was that the size of an excavated crevice had an influence on the amount of shrimps that subsequently gathered in it. When there were more helpers around, the space that could be created was bigger and more shrimps could be gathered.

"Helpers in Neolamprologus obscurus extend and maintain the excavated cavities, and by doing so, contribute to an increase in food abundance inside the territory of breeding females," explains Tanaka.

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Birds and primates share brain cell types linked to intelligence

Neuronal cell types in the brains of birds linked to goal-directed behaviors and cognition are similar to cells in the mammalian neocortex, the large, layered structure on the outer surface of the brain where most higher-order processing takes place.

In a new study, published this week in the journal Current Biology, scientists from the University of Chicago show that some neurons in bird brains form the same kind of circuitry and have the same molecular signature as cells that enable connectivity between different areas of the mammalian neocortex. The researchers found that alligators share these cell types as well, suggesting that while mammal, bird and reptile brains have very different anatomical structures, they operate using the same shared set of brain cell types.

"Birds are more intelligent than you think, and they do clever things. So, the question is: What kind of brain circuitry are they using?" said Clifton Ragsdale, PhD, professor of neurobiology at UChicago and senior author of the study. "What this research shows is that they're using the same cell types with the same kinds of connections we see in the neocortex, but with a very different kind of organization."

Both the mammalian neocortex and a structure in the bird brain called the dorsal ventricular ridge (DVR) develop from an embryonic region called the telencephalon. However, the two regions mature into very different shapes. The neocortex is made up of six distinct layers while the DVR contains large clusters of neurons called nuclei.

Because of this different anatomy, many scientists proposed that the bird DVR does not correspond to the mammalian cortex but is instead analogous to another mammalian brain structure called the amygdala.

In 2012, Ragsdale and his team confirmed a 50-year-old hypothesis by University of California San Diego neuroscientist Harvey Karten that proposed the DVR performs a similar function to the neocortex, but with dramatically different anatomy. In that study, the UChicago researchers matched genetic markers of the "input" and "output" neurons of the mammalian neocortex with genes expressed in several bird DVR nuclei.

In the new study, led by graduate student Steven Briscoe, the team found that other populations of neurons in the bird DVR share molecular signatures with neocortical intratelencephalic cells, or IT neurons. These IT neurons form a critical link in the circuitry of the neocortex. They help communicate between different neocortical layers and across cortical areas from one side of the brain to the other. The team then extended their work from birds to reptiles and identified IT neurons in a similar place in the alligator DVR.

"The structure of the avian DVR looks nothing like the mammalian neocortex, and this has historically been a huge problem in comparative neuroscience," Briscoe said. "Anatomists have debated how to compare the DVR and neocortex for over a century, and our identification of IT neurons in the bird DVR helps to explain how such different brain structures can give rise to similar behaviors."

The research suggests an interesting possibility that birds and primates evolved intelligence independently, developing vastly different brain structures but starting with the same shared sets of cell types.

Read more at Science Daily