It can happen for a lot of reasons. Some populations specialize in hunting in very shallow water or even running themselves into the beach, which means they can get stuck if they make a mistake. But most of the time it is a result of severe illness, which causes the animal to either lose the ability to navigate or they just lack the strength to swim against the current.
Motherofkittens86 t1_j3yq2ki wrote
Reply to comment by VSBakes in Killer whale dies after grounding itself on Florida beach by katherinezetajones
It can happen for a lot of reasons. Some populations specialize in hunting in very shallow water or even running themselves into the beach, which means they can get stuck if they make a mistake. But most of the time it is a result of severe illness, which causes the animal to either lose the ability to navigate or they just lack the strength to swim against the current.