Florida Worm Lizard

Image: Mary Keim
Rhineura floridana

It's a worm but it's a lizard but it's a worm!

The Florida Worm Lizard is a very special Worm Lizard found only in Florida, U.S. Why is it so special? Because it's the only Worm Lizard in all of North America! So much space...

Yet the entire population lives in just a patch of one peninsular.

The Florida Worm Lizard is certainly not a worm, though you could easily be fooled. With their underground, burrowing lifestyle and a pink body that appears to be segmented, they look and live a lot like a friendly earthworm. And at some 30 cm (1 foot) long, quite a large one at that. They even climb up to the surface when it rains too hard!

However, Worm Lizards are actually the reptiles who belong to a group known as Amphisbaenia. This in turn is within the order Squamata, which also contains all the snakes and lizards. The exact details of the relationship between snakes, Amphisbaenians and all those four-legged reptiles we call lizards is far from clear, but I doubt our Florida Worm Lizard worries his pretty, little head about that.

Video: yuzurename

The word Amphisbaenia means "to go both ways". It's a name they share with a mythical beast who was a serpent with a head on both ends, so it could move both forward and back. That wouldn't be so bad except they also had a venomous bite on both ends. Such is the way of mythical beasts.

Real Amphisbaenians are similar, except they don't have even one venomous bite let alone two, and their tail isn't actually another head. It just looks like it because their tail end stops abruptly instead of tapering away and their head looks so featureless. They can still move forward and backward through their burrow even without an extra head, which may be even more impressive than the mythical beast.

Image: Mary Keim

Burrowing through darkness, Worm Lizards scarcely have a need for eyesight. Their eyes are tiny and covered in scales so they're protected from the soil, but they can still tell light from dark. Their nostrils also point backwards so they don't get filled with mud all the time. It would be very difficult for the limbless Florida Worm Lizard to carry a handkerchief to sneeze into. In fact, the famous Mexican Mole Lizards, or Ajolotes, are the only Worm Lizards with any limbs whatsoever and they don't seem to carry tissues, either.

Amphisbaenians have a bony, little skull for pushing earth out of the way, while their lower jaw slots neatly into an overbite that ensures they don't get a mouthful of soil as they seek out real earthworms and other subterranean creatures to plunge their surprisingly powerful jaws into.

Image: President and Fellows of Harvard College

Their skin meanwhile is rather loosely attached to the body and its segmentation means that it can concertina. Worm Lizards can push their skin forward, press it up against the wall of their burrow and then use their muscles to pull the trunk of their actual body forward. It's quite disgusting, but life underground was never easy and no-one can see them anyway, so they can pretty much do whatever they want.

With these subterranean habits it's no wonder Worm Lizards are so little known and difficult to study. At least with the Florida Worm Lizard we know they lay a mere 1 to 3 eggs in summer, which hatch a few months later.

It's interesting to note that there were once many more Worm Lizards throughout North America. Fossils have been found dating back over 60 million years, to just after the reign of the dinosaurs. It's clear that the Rhineuridae family used to be a lot bigger and more widespread than it is now. All that's left is a single species clinging on to a single state by the skin of its teeth. Thank goodness for that weird, loose, wrinkly skin!