THE MEXICAN MOLE LIZARD
Imagine what would happen if an earthworm, a lizard, a snake and a mole went on a night out, had too much too much tequila and let their guard down. Setting aside genetic incompatibility and the sheer ridiculousness of such a scenario, you might end up with something a bit like the Mexican mole lizard (Bipes biporus).
Also known as the five-toed worm lizard, the Mexican mole lizard is a bizarre-looking reptile found in the sandy soils of the Baja California Peninsula in Mexico. It belongs to a group called the amphisbaenians, or worm lizards, which typically have no legs – a trend this critter bucks. Sitting behind its stubby head, at the apex of a slender, pink body, is a single pair of massive hands with clawed digits. Living up to the mole part of its name, the Mexican mole lizard uses these appendages to shovel soil and clear a path through its subterranean world. Unlike a mole, however, when its front limbs aren’t in use, they’re folded away like an IKEA breakfast bar, into recessed areas on the creature’s sides.
Evolution favours a ‘use it or lose it’ strategy. Features that help living things to survive tend to persist over time, while the deadwood gets discarded. In the distant past, the Mexican mole lizard used to have hindlimbs, as evidenced by the vestigial stumps that can be seen on X-rays. But they got in the way when the reptile was moving around, so they disappeared over time. Similarly, its eyes have shrunken to vestigial dots, because it lives in the dark. Meanwhile, the Mexican mole lizard has evolved to have skin covering its ear canal because, let’s face it, who wants to get grit in their lugholes!
Because they spend most of their time underground, comparatively little is known about the ecology of the Mexican mole
lizard. Like earthworms, their activity is thought to change the physical and chemical properties of the soil that they live in. They’re also predators and prey. They’re eaten by snakes and birds, and feed on the likes of ants, termites and earthworms.
The word ‘amphisbaenian’ means ‘to go in two separate directions’, which is apt. By pulsing and relaxing its segmented body, the Mexican mole lizard can go forwards and backwards, but these aren’t its only moves. When alarmed, it thrashes around so vigorously that it can lift off the ground, and if a predator grabs its tail, it will
“ITS EYES HAVE SHRUNK TO VESTIGIAL DOTS, BECAUSE IT LIVES IN THE DARK”
detach it and grow another one. This is called autotomy.
Perhaps because of their elusive nature, Mexican mole lizards have become the focus of local folklore. Some believe that if a person goes to the toilet outdoors, or otherwise chooses to expose their private parts, the Mexican mole lizard will use its little hands to climb inside an orifice and either impregnate a woman or eviscerate a man. It’s butt-clenching stuff, but thankfully there’s no reason to believe the myth is true!