Cleaner wrasse have revealed a remarkable new side of fish intelligence. Marked with fake parasites, they used mirrors to ...

In 2011, a study published in the Journal of Veterinary Behavior saw researchers conduct an experiment involving 40 dogs to test whether canines were able to understand the concept of reflection. Each ...

In the new experiment, roosters made fewer alarm calls, meant to warn peers of predators, when placed in front a mirror versus when standing near another rooster. Stefano Spaziani / picture alliance ...