Board Thread:General Discussion/@comment-26184563-20130421015649/@comment-995426-20160428202405

They aren't human, but they are part human from the mutation. That's always been my understanding. Just like Splinter became part rat, Kirby became part bat (until his retromutation), Rockwell became part monkey, Bradford became part dog, Xever became part fish, Baxter became part fly, Steranko became part rhino, Zeck became part warthog, Martin Milton became part sparrow, and Jason became part gecko. Slash, Leatherhead and Pete also became part human, and Pete even has a very human-looking torso with human skin despite having originally been a pigeon. Donatello said during Parasitica that he was surprised at the wasps' particular mutation because most mutations seen thus far had been anthropomorphic (human in form), including themselves. And the turtles are clearly part human: So yes, the turtles are reptiles. But their mutation has also made them partially human, and thus also implicitly apes/primates/mammals. Where these human mutagenetic traits came from is never explained, but they certainly had plenty of human handlers, including Splinter himself.
 * They have a humanoid frame, including an upright bipedal stance and human postures.
 * They have human vocal cords&mdash;real turtles have no vocal cords and can only make limited noises by forcing air through their throats.
 * They sweat to keep cool&mdash;real turtles cannot sweat.
 * They shiver to keep warm&mdash;real turtles cannot shiver. Warm-blooded creatures such as mammals do shiver.
 * They have a full set of human teeth&mdash;real turtles have no teeth whatsoever.
 * They have full human intelligence.

And considering the circumstances of their mutation, it could have gone very differently&mdash;Splinter could have become a humanoid turtle, and the pet turtles could have become non-sentient turtle/rat hybrids, or they all could have become kind of bizarre human/turtle/rat triple hybrids. And who's to say&mdash;maybe Splinter does have some unnoticeable turtle qualities and maybe his sons do have some unnoticeable rat qualities. We may never know.

Remember what Raph said in Rise of the Turtles? The mutagen could turn Snake into someone handsome like himself, or something gross and deformed "like Mikey over there." But judging from the mutations of characters like Timothy, this wasn't necessarily an unrealistic assessment.

Don't get me wrong&mdash;I can't stand the super-ugly mutations this series likes to play with, but I have to admit there's at least some realism to it. Though even more realistically than that, most real-life major random mutations do little more than cause malignant cancer.