Pliny the Elder 9.26 trans. Rackham (1938):
Another dolphin in recent years at Hippo Diarrhytus1 on the coast of Africa similarly used to feed out of people’s hands and allow itself to be stroked, and play with swimmers and carry them on its back. The Governor of Africa, Flavianus, smeared it all over with perfume, and the novelty of the scent apparently put it to sleep: it floated lifelessly about, holding aloof from human intercourse for some months as if it had been driven away by the insult; but afterwards it returned and was an object of wonder as before. The expense caused to their hosts by persons of official position who came to see it forced the people of Hippo to destroy it.
This dolphin was so into people that the Governor covered it in unguents, which put it in some kind of coma and/or snit, and it was such a popular tourist destination for rich and powerful Romans that the locals decided to just kill it so they wouldn't have to host so many people with expensive tastes.
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I realize that "Hippo Diarrhytus" is maybe the funniest place name imaginable. Unfortunately afaict it is just one of several towns called Hippo, which may or may not have to do with horses, and specifically it is the one "bisected by rivers", or where some rivers meet.