Enjoying your banana?   This is Kemosabe. He's a prehensile tailed porcupine, also known as a coendou. These guys are found in Brazil and they live up in the trees. You can tell he is made to live in the trees because that amazing tail helps him hold on and these feet also help him hold on. He kind of walks like a penguin. He wraps his little feet around the branches so he can just hang out all day long finding different foods to eat.   [Kemosabe vocalizing]   Now, he is a rodent, so that is very different than a lagomorph. And, if you don't know what a lagomorph is, I'll tell you. It is a rabbit. A lot of people think rabbits are rodents, but that's not true. Rabbits are lagomorphs. Instead of having two top incisors and two bottom ones, they actually have four top incisors. Two, and then two small ones right behind their other front incisors. So that's what makes lagomorphs and rodents different.   You agree?   It is nighttime right now. And, so, Kemosabe is nocturnal and he's very awake right now. You can hear the crickets and some other nighttime animals going on. You can hear some of the birds squawking because they're going, "Hey, turn out those lights." But we wanted to show you what Kemosabe does in the nighttime.   We treat him medically - the veterinarians treat him medically like a giant rat. It's basically what he is, because he's a rodent and he's not related to cavies; he's not related to other types like hamsters or any animals like that. He is most closely related to a rat, so we treat him medically just like a giant rat.    With those giant teeth. Even though you only have one on top now, huh?    Yeah.   What do you think?   [Kemosabe vocalizing throughout]   Yeah? Tell me some more.    So, rodents - this is a rodent's skull, this is actually a Patagonian cavy skull - I wanted to show it off so you can see what a rodent's teeth actually look like.    If you can take a close look at this.    This skull was actually shown on SciShow with Hank and Emily and, ah, we were talking-- we were talking about the cavy there.    But I wanted to give you a closer look at this, if you can see that these incisors are just amazing. You can see the little shelf right there where they're going to chisel their food down. There's actually nothing there, and then there's these back molars back there.   So, Kemosabe, uh, the porcupine is a rodent. He has those incisors just like this, but his top incisor went rotten. It goes all the way back into here, so it's a huge incisor. And this is actually what we've trimmed off of his remaining tooth.   So, because they chisel and they're ever-growing and they chisel in the wild, they keep their teeth very short. They keep them in check. But because Kemosabe has one tooth on top and two on the bottom, this tooth actually goes right in between - can you see that? - goes right in between those two, and they just get longer and longer and longer.   So this is actually the amount we had to trim off; the vet had to trim off to maintain his teeth so he could still continue to eat. If they get too long - you can imagine, they can only open their mouth about that wide - so if their teeth are getting much longer, they're eventually not going to be able to open their mouth wide enough to be able to eat.