At least once a week (if not once a day) someone suggests an implication of a character's name to their species and has to be told why e621 doesn't do that.
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Answer: Because characters are very often species-swapped, the most common probably being a furry/pony character depicted as a human.
Some characters also have their species as part of their formal, trademarked name, such as Sonic the Hedgehog. Thus, the name stays Sonic the Hedgehog when he isn't actually a hedgehog.
Updated by Knotty Curls