Mind the Tail...

One of the first things that a new keeper is taught when working with lizards, geckos and skinks among them (but with a few exceptions) - if you ever do have to pick one up, don't do it by the tail.  Because if you do, things like this happen.

In my first job as a zookeeper post-college, my curator had a tank of green tree skinks from the Philippines that he was very fond of... and that it was my job to care for.  They were very lovely.  They were also lightning fast and tended to dash out as soon as you nudged the lid of the tank open even a little bit.  Every time he saw me go to feed them, he would cheerfully remind me of how miserable he would make my life if I let them go... or if, in catching them, I caused them to shed their tails.  

The process is called "Autotomy" or "Self Amputation."  The idea is that the tail is left twitching around and holding the interest of the potential predator while the lizard itself skedaddles for the horizon.  I suppose that both the predator and the would-be prey walk away as winners in this case.  The lizard because... well, because it walks away at all, and the predator because getting to eat a tail is better than getting to eat nothing at all, I suppose.

Now, for many lizards, if you do this, the tail will grow back.   Some of them may even grow back two.  For others, this is a "one and done" kind of deal.  At the very least, it's not the kind of party trick that a lizard would want to do for fun.  It can be biologically expensive to grow a new tail.  Plus, your balance is probably off if you are used to having one, and you can't use it for combat or defense until/if a new one grows in.

Tails tend to be delicate structures for many animals and not the ideal place to handle them.  For some arboreal animals with very strong, muscular tails, the opposite can be true - for a binturong or a prehensile-tailed porcupine, the tail serves as a handy built-in leash.

Going back to my curator as his tree skinks, they happened to be a species that would regenerate their tails if they were dropped.  That didn't matter to him.  Even though they would grow back, it would ruin the aesthetic in his view.

Aficionados of Marvel comics might recall lizard autotomy in regards to one of Spiderman's most enduring villains.  Scientist Curt Connors wants to regrow his lost arm and, knowing of the ability of lizards to regenerate their tails, devices a formula to replicate the phenomena in himself.  It works, in that it grows his arm back.  It also doesn't, in that it turns him into a giant humanoid lizard with a desire to lead reptiles in conquering the world.

I mean, I've heard worse plans...