Types of hook-nosed snakes

Gyalopion is a small North American genus in the family Colubridae, the largest and most diverse snake family in the world. The genus holds just two species, the Chihuahuan Hook-nosed Snake (Gyalopion canum) and the Thornscrub Hook-nosed Snake (Gyalopion quadrangulare). Both are tiny, secretive ground-dwellers of the arid and semi-arid borderlands. The defining feature is the sharply upturned, hook-like rostral scale at the tip of the snout, an adaptation for pushing through loose desert soil. They reach the northern edge of their range in the southwestern United States, mostly Arizona, New Mexico, and Texas, and extend south into northern and central Mexico, favoring desert grassland, rocky slopes, and thornscrub.

These are short, stout snakes, generally under about 15 inches long, with smooth scales and a blunt, shovel-like head. The Chihuahuan species tends toward a gray to tan ground color crossed by many narrow dark bands, while the Thornscrub species is more boldly patterned. Their small size, the distinctive upturned snout scale, and a habit of staying hidden underground make them easy to overlook. Like many fossorial colubrids, they spend most of their lives below the surface or under rocks and debris, emerging mainly at night or after warm-season rains.

Hook-nosed snakes are harmless to people. They are not front-fanged venomous snakes and pose no medical danger; their tiny mouths feed on small invertebrates such as spiders, centipedes, and scorpions rather than anything that would threaten a human. When alarmed they may writhe, evert the cloacal lining, and make a popping sound, a bluff display that is startling but entirely defensive. As with any wild snake, the responsible approach is to observe and leave it be rather than handle it. If a snakebite from any species ever causes concern, contact emergency services or US Poison Control at 1-800-222-1222.