Gyalopion canum, commonly known as the Western hooknose snake, is a species of small colubrid snake endemic to the United States and Mexico. It is sometimes referred to as the Chihuahuan hook-nosed snake because it is commonly found in the Chihuahuan Desert.
It was once classified in the genus Ficimia, but was reclassified due to distinct morphological characteristics.
It is found in the United States, from western Texas to southeastern Arizona, and into northern and central Mexico.
The Western hooknose snake is a small species, growing to 36.5 cm (14 3⁄8 in) in total length. They are gray or grayish brown in color, with 25-48 dark brown or black blotches down their back, and a cream-colored underside. They have a slightly upturned snout, which gives them their common name.
The smooth dorsal scales are arranged in 17 rows at midbody.
Hooknose snakes are nocturnal burrowers, most often found under rocks.
They prefer slightly sandy habitats, near a permanent water source.
Their diet consists primarily of spiders and centipedes, but they will also eat small snakes and scorpions.
They are oviparous. Sexually mature females may lay up to 5 eggs in June.
One of its primary defensive behaviors is to make a popping noise with its cloaca, i.e., farting. According to an article in the August, 2000 issue of Discover magazine, during a laboratory experiment carried out by Bruce Young, a morphologist at Lafayette College, the snakes only farted when they felt threatened, and some farted so energetically that they lifted themselves off the ground.
Gyalopion canum is quick in short bursts or spurts.