Scientists have long asked whether reptiles can recognize themselves. Do they just do things because they have to survive? For a time, most scientists thought that only mammals and birds could really understand themselves. Researchers who study animal cognition conducted new research using scent, the sense snakes rely on most, to navigate the world.
How eastern garter snakes use scent to test self-recognition
For more than fifty years, people used a simple test to see if animals knew they were themselves. This test was called the mirror self-recognition experiment. In this test, scientists marked an animal's body with dye. They then watched to see whether the animal would use a mirror to inspect the mark. Animals that rely heavily on sight, such as monkeys, dolphins, and elephants, have tended to do well on the test. Animals that rely more on smell, such as snakes, have not done as well. Snakes have limited vision, so they use their tongues to sample chemical cues in the air.
Some scientists argued that the test disadvantaged animals that rely on smell. Researchers therefore developed a test designed for snakes. This test used scent cues instead of mirrors. The scientists wanted to see whether eastern garter snakes could distinguish their own scent from other scents. According to the National Institutes of Health, animals that live in groups may recognize themselves when tested in ways suited to their behavior. In this test, the snakes did not have to look in a mirror. Instead, they smelled different scents to see if they could pick out their own smell.
