The first thing every monkey does if it recognizes itself in the mirror is check its crotch.
Shanghai-based neurobiologists conducted an experiment where they seated dozens of primates before a mirror and watched their reactions to their “double.” Nothing happened for a time, but when the monkeys realized they were seeing their own reflection, the first thing they did was check their crotch.
Sources: cell, ibtimes
Dolphins can talk on the phone and recognize the one they’re talking to.
Every dolphin has its own signal name that appears in adolescence and is kept their whole life. It’s known that dolphins can tell their relatives’ signals from all the rest. They’re able to recognize each other with the help of short tone perception. People also recognize their opponents on the phone by voice, so if dolphins could talk on the phone, they would know each other.
Sources: livescience, telegraph