I was wondering about an iguana losing it's tail. I have always wondered about that. Mine has not lost it's tail, I just wonder how it's done. I have seen iguanas with their tails missing and I don't really get how they do that. It is voluntary or does it have to be really pulled off? -Mal

They lose their tail because of an escape response mainly. When the iguana is under a lot of stress (i.e being chased by a predator) the body will release certain chemicals. When the predator grabs the ig's tail, those chemicals react and break the tail off just above where it's being held. It breaks off at certain vertebrae only. These vertabrae are somehow disconnect themselves from the rest and thus separate the tail. It's called autotomy. That's why some very nervous igs can lose their tails without even being touched (although this is very rare). It's just a stress factor. The tail can also be severed manually by accident, such as when the iguana gets caught in something.

Heather