Dolphins learn tool use from peers

[Catherine]

Many of the species that use tools learn to do so from their mothers as part of their survival training.  It has been observed that Dolphins are learning tool use from their peers, dolphins of the same age group that they hang out with. This kind of peer to peer learning has been observed in great apes. Dolphins and apes are not closely related, but they both have higher intelligence. 

So hunting skills and tool use skills are taught by the mother, but they are also passed on by dolphins of the same age.  

https://www.nationalgeographic.com/anima...reat-apes/

The key point here is that knowledge is passed on. If a member of a species learns some better way of doing something they can teach other members of their species how to do it. This definitely needs more study. Are dolphins and great apes the only species that do this. It will take more study before we have that answer. What we do know so far questions our understanding of animal intelligence. Clearly animals are more intelligent that was previously thought.