Mexican Mole Lizard

It is none of those exactly. It belongs to a distinct group of reptiles called amphisbaenians, or worm lizards, which are separate from both true lizards and snakes on the reptile family tree, although all three descend from a common reptilian ancestor. Amphisbaenians are highly specialised burrowers with reduced or absent limbs, ring-marked bodies, and skulls built for pushing through soil, and the Mexican mole lizard is one of only a few of them that retain any limbs at all. Its worm-like appearance, with a pink, segmented-looking body, is a case of convergent evolution toward a shape that works well for life underground, not evidence of any close relationship to actual worms.

The single pair of short, strong, clawed forelimbs is used specifically for digging, loosening and scraping soil away at the front of a new tunnel and helping pull the body forward, after which the limbs fold flat against the body so they do not impede movement through the completed burrow. The hind limbs, along with any hip structure to support them, have been lost entirely over evolutionary time because they would provide little benefit and would get in the way in a narrow tunnel, where the rear of the body is used mainly to brace and push. Keeping only the forelimbs represents an intermediate stage in the widespread evolutionary trend among burrowing reptiles toward complete limblessness.

Living in near-total darkness, it relies very little on vision and instead detects prey largely through sensitivity to sound and to vibrations transmitted through the soil, picking up the movements and activity of ants, termites, beetle larvae, and other small invertebrates in nearby chambers and tunnels. Its skull and jaw are adapted for seizing and processing prey in the confined space of a burrow, and it will also take small surface animals such as lizards that fall into or venture near its tunnels, making it an opportunistic predator within its subterranean world rather than a strict specialist on any one prey type.

It is found only on the Baja California peninsula in Mexico, where it lives in areas of loose, sandy, or loamy soil in desert scrub and dry forest, and even within that range it is rarely seen because it spends almost its entire life below ground. People most often encounter one after heavy rain, when digging in a garden or field, when turning over rocks or debris, or occasionally on roads or paths at night, and its bright pink colour and strange two-legged worm-like form make it unmistakable and frequently startling to anyone who comes across one for the first time.