The tightness and duration of a constricting snake’s death squeeze are timed to perfection, matching the heartbeat and weakening state of the snake’s unfortunate prey, according to a study published in the latest Royal Society Biology Letters.
The findings reveal that snakes are far more intelligent than previously thought, capable of complex functions typically reserved for “higher” vertebrates. They are also master hunters, ready to kill at any given moment.
“A snake first detects its prey with visual and chemosensory means,” lead author Scott Boback, an assistant professor of biology at Dickinson College, told Discovery News. “In addition to these, Boas also have heat sensitive neurons located beneath their lip scales. These neurons can sense temperature differences in their environment, such as an endothermic prey animal.”
“They can kill their prey through a variety of means, including constriction, envenomation or a combination of both,” Boback added.
For the study, Boback and his colleagues caught 16 wild Boas, raising them in a temperature-controlled lab on a diet of dead chicks and rats. Some rat cadavers were outfitted with a simulated heart that permitted the researchers to control how it pumped.
The scientists next dangled the warmed, outfitted rats tantalizingly over the snakes. As the snakes went into their death grip, Boback and his team analyzed the pressure generated by the snakes. The snakes responded to the beating heart, constricting longer and with greater total pressure until the heartbeat ceased.
This video shows a boa striking and constricting during a kill.
Snakes naïve to live prey also responded to the simulated heart, suggesting that the behavior is partly innate. But experienced snake hunters perfectly timed their kills to the heartbeats.
“That suggests to us that snakes can learn how to change their constriction duration and pressure to effectively kill their prey,” Boback said.
He also explained that since snakes use a variety of cues to monitor the state of their victims, they would not waste their time squeezing an animal that does not die after a certain period of time.
During the study, if the researchers kept the simulated heartbeat in the rat cadaver going, the snake did eventually release the rodent.
Read more at Discovery News
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