The common believe is that animals don’t have long term memories and cannot recognize people. It is true in some animal species, but others have proven higher intelligence. Studies have been done to determine animal mental capacities. Studies on primates have shown that they can remember and learn new things. They also teach their young how to use tools and hunt, therefore primates must have memories. Cetaceans (whales and dolphins) have a good memory as they can be trained (in captivity). They teach their young how to hunt and play. A Bottlenose dolphin that was in a rehabilitation center in Australia, started swimming backwards on her tail by studying the captive dolphins performing this trick, and when she was released back into the ocean she started teaching this “new” game to her pod.
“How good is cetacean´s memory?” Resent research suggest the possibility of dolphins possessing the world´s most impressive memories e.g. captive Bottlenose dolphins can recognize the names of their old pool mates after being separated for more than 20 years. A wild dolphin that helped escort boats safely to harbor declined to escort one boat after a passenger took a shot at it.
A normal assumption is that fish only has a 3 second memory, but researchers have seen that fish can remember potential predators for months and some species can work in teams. Migratory species needs to have some kind of memory as migrating whales keep their calves with them even when the calves have stopped nursing from their mother in order to teach the calf the migration route.