This article is a ‘Science Story’ – while it attempts to be essentially factual, certain details have been slightly exaggerated or simplified.
One of my favourite stories to tell is about the tails of certain lizards.
As you of course know, lizards have a tail. One cool thing about some of these lizards, is that their tail can separate from the rest of their body. {Pause for exclamations of disbelief, and comments that they have pet lizards, etc} There is a good reason for this. When an animal (a predator) is hunting a lizard, the easiest part to grab is the tail. If the tail can separate from the rest of the body, the predator is left with the tail and the lizard has a chance to escape. This is also particularly helpful if the lizard is bitten by a poisonous snake – it can drop its tail before the venom spreads, and save its life.
Now some of you might have known that, but what I bet you don’t know is that some of these lizards have two brains. {Slight exaggeration -the ‘brain’ in the tail is a small collection of neurons} {Pause for gasps of shock} These lizards have a main brain in their head, and a tiny little brain in their tails. When their tail is attached to the rest of their body, the brain in their head will control the tail. However, when the tail is separated from the rest of the body, the little brain in their tail can make the tail do summersaults, flips, and acrobatics. As weird as this seems, think for a moment about when you are playing hide-and-go-seek – if you are ‘it’ you are looking for the slightest movement, whereas if you are hiding, you try to stay very still. Animals are very sensitive to movement – it helps predators spot their prey, and prey spot potential predators. Having the tail move around draws the predator’s attention towards it, increasing the chances that the lizard will manage to get away.
There is one more interesting thing left though. If, for some reason, the predator doesn’t eat the tail, the lizard will come back and eat its own tail. After all, no reason to let a perfectly good snack go to waste. In the end, the lizard will grow a new tail, it won’t happen overnight, but it will happen eventually – whether or not it eats it own tail. {It usually takes between 3 months and 2 years for the tail to grow back}
