When most scientists hear the term “animal self-awareness,” they think of chimpanzees, crows, and elephants.
Using an innovative twist on the mirror test, researchers have found the first evidence that garter snakes can distinguish themselves from other snakes using smell rather than vision.
“Reptiles are understudied,” said Norm Miller, a comparative psychologist at Wilfrid Laurier University in Ontario, Canada, and author of a paper published Wednesday in Proceedings of the Royal Society B. Stated.. “There's a prejudice that they're boring, not-very-cognitive animals, but that's completely untrue. That's why we're so interested in studying them and showing the complex cognitive functions they're capable of.” That's one of the reasons I had one.”
According to Dr. Miller, one of the traditional signs of an animal's cognitive ability is generally the mirror test, i.e. whether an animal can learn to recognize itself in a reflective surface, and this trait has been developed in more sophisticated ways. It is believed to be a substitute for intelligence. Developed by primate researchers in the 1970s, the test involves marking with paint a spot usually visible only in an animal's mirror and waiting to see if any changes are investigated.
Similar tests were then conducted on a variety of species, including elephants (passed), pandas (failed), roosters (passed), and even wrasse-like fish (passed).
However, the mirror test is primarily aimed at visual animals. Miller said many species, including snakes, rely primarily on their sense of smell. In 2017, researchers devised an olfactory version of the test for dogs. (They passed.)
In the new study, two different species of snakes were tested. At one end of the spectrum is the eastern North American garter snake, a predator of insects and fish with a surprisingly complex social life. The other is the African ball python, a snake that primarily sits alone and ambushes rodents.
Snakes, like humans, have oil on their skin that leaves a scent trail. The researchers rubbed makeup-removal pads along the undersides of both snakes and collected scent samples, some of which they added olive oil to. They placed paw pads at each end of a long, narrow box, giving the snake several options. Is it my own scent or straight olive oil? Their own smell is fixed with olive oil. and modified or unmodified odors of other snakes of the same species.
The researchers measured the snakes' interest by measuring how long they flicked their tongues to taste the air. A longer period of time indicates sustained interest, he said. There was no obvious distinction between ball pythons. However, garter snakes focused on their own tampered scent and ignored changes in other snakes' scents.
“Basically, they don't seem to care if other people smell strange,” Dr. Miller says. “If you smell something strange, you need to investigate it.”
Recent research has shown that eastern garter snakes are highly social and gather in groups. They hibernate in large flocks during the winter, and form networks of “friends” during the active season.
As a more social species, they may be more sensitive to the need to distinguish themselves from other species. One possible explanation for how self-awareness works, Dr. Miller said, is the ability to recognize the difference between self and “non-self.” “That ties in with social behavior.”
But he added that it's difficult to say whether the ball python's failure to pass the test was due to a lack of ability or a lack of interest. Continuing research in his lab suggests that while ball pythons are more solitary, they are also socially complex.
However, with more than 5,000 living snake species living in a variety of environments, the snake family as a whole has a wide range of opportunities to understand what ecology and behaviors drive animals to differentiate positively. He said that it is being provided. Future trials could focus on arboreal species or venomous snakes like rattlesnakes. Recent research suggests that these venomous snakes prefer to nest with relatives and are less stressed around other snakes. Indeed, rattlesnakes are “more difficult to handle in a lab full of undergraduates,” Dr. Miller says.
“I think in many ways their experimental paradigm is more powerful than the mirror test.” Rulon Clark, a biologist at San Diego State University who studies social behavior in snakes, said he was not involved in the study. “a Highly reflective mirror surfaces do not have many environmentally friendly analogues. But encountering and understanding the importance of chemical clues left behind by yourself or other animals of your kind is probably a very important aspect of the natural history of these animals. ”
“Our research connects how snakes experience themselves and how they experience the world around them,” said Dr. said study author Morgan Skinner. “This also shows that if we can do this effectively in experiments, we can discover surprising cognitive abilities.”
Miller said little is known about the social structure of snakes and other reptiles. “And if we want to understand the basic components of social structure, we need to study a wider range of species, not just rats and pigeons all the time.”
