Bachia lizards – look, no hands!
Legend tells the story of Oedipus, who faced the sphinx guarding the gates to the city of Thebes. To enter, the monster presented him with a riddle:
“Which creature has one voice and yet becomes four-footed and two-footed and three-footed?”
Oedipus was able to solve the sphinx riddle, granting him entrance to the city. He later became the king of Thebes and married his own mother – but that’s another story.
The answer to the sphinx riddle can be quite intuitive if you stop to think about it, but what if I told you there are animals that fit that description quite easily? It is with my own eyes that I have seen arachnids staring their life with eight legs, losing some of them during growth, and then growing them back like nothing happened in the amazing process of regeneration. Some hemimetabolous insects and even amphibians can do it just as well. And what if I told you there is an animal that is born with legs, and by the end of its life it loses all of them but one? Introducing Bachia, a genus of strange long-bodied lizards.
The adult Bachia lizards resemble snakes, having an elongated body and reduced limbs. They have small eyes and no external ear openings. These are adaptations for a subterranean lifestyle, as these lizards spend most of their time moving through the leaf litter and in the soil looking for their favorite food – soft-bodied insects. They usually hunt termites and ant brood in underground nests. Occasionally they make their way into decomposing wood, where they will not hesitate to snag a juicy beetle larva if the opportunity presents itself. I encountered my first Bachia while it was hunting termites moving on a trail.
Bachia are not to be confused with other snake-like lizards such as limbless skinks, slowworms, glass lizards, or amphisbaenids, all members of other groups. Bachia lizards belong to family Gymnophthalmidae, also known as microteiids or spectacled lizards. Their closest relatives are the skittish whiptail lizards. The name “spectacled” refers to their transparent eyelids, allowing these lizards to see even when their eyes are closed. Most members of the family are normal looking lizards, like this common root lizard (Loxopholis parietalis).
As the name suggests, microteiid lizards are generally small. How small? Very small.
Ok, I’m cheating here a little, after all this is a juvenile specimen. But generally speaking, a microteiid lizard can sit comfortably in the palm of your hand, and you will still have room for two or three more lizards.
The genus Bachia contains about 30 species, many of which are endemic. The species I have encountered the most is Bachia trisanale, it is one of the more common species with a wide distribution in South America, occurring in Ecuador, Peru, Bolivia, Colombia, and Brazil.
One of the most interesting aspects of Bachia lizards is their limbs. All species have a long body with very small limbs. Members of the genus can be easily divided into groups by their limb structure and the level of reduction in the hindlimbs. In many species the hindlimbs are extremely reduced to tiny hooks or absent altogether. Few species, like the Bachia trisanale appearing in this post, lack hindlimbs and show digit reduction in the forelimbs as well. Interestingly, limbs can also be lost throughout the lizard’s lifetime. Although a leg can be lost following an injury, it can also happen due to tissue erosion caused by the lifestyle of digging and burrowing through coarse soil containing clay particles. The hind legs (if present) usually go first, shrinking to tiny knobs or disappearing completely. The stronger forelimbs are eventually eroded as well, first the tiny digits, and then the remainder of the leg. Judging by several specimens that I have encountered, the forelimb loss is even a directional change – usually it is the right forelimb that disappears first, followed by the one on the left side. It is common to find old Bachia lizards with only one limb! Usually by that time the remaining leg has lost its digits entirely, and looks like a small stub.
Surprisingly this has no negative effect on the lizard’s locomotion. One might even argue that losing the limbs makes it more terradynamic, allowing it to “swim” freely in the substrate with no drag.
So when you are feeling down, remember that there are small lizards that look like a noodle, diving face first into the dirt after pesky termites and ants. And they do it with no hands!