Reptiles
Sand Boa
Eryx · also called sand boa
A sand boa is a boa that gave up the trees for the ground and then went under it. Short, blunt, and thick, with tiny eyes set on top of a reinforced head, it spends its life buried in the dry soils of Africa and Asia, lying in wait beneath a rodent trail with only its eyes exposed. The Kenyan species, small and unshakeably calm, has become one of the most popular pet snakes in the world.
Overview
Sand boas are the genus Eryx, small constrictors of deserts, dry grassland, and loose farmland soil from North Africa across to India. They hunt rodents, small birds, and lizards from ambush under the surface, striking upward and dragging prey down into the sand. Everything about the body — blunt head, small hard scales, high-set eyes, stubby tail — is built for burrowing.
A dwarf boa
Despite the name “boa”, these are not relatives of the giant tropical constrictors. They belong to the Erycinae, the same small subfamily of burrowing dwarf boas as the North American rosy boa and rubber boa. Like all boas they bear live young — litters of about 5 to 20 — and in most species the female is far larger than the male, sometimes more than twice his length.
In captivity
The Kenyan sand boa is a staple beginner snake: 40–80 cm, docile, a simple dry burrowing setup, a reliable feeder, and available in many colour morphs. It spends most of its time buried and surfaces to take food, which owners either enjoy or find frustrating.
Status
Least Concern for most species, which are widespread if rarely seen. Several Indian sand boas are heavily collected for the pet trade and for superstition and now have legal protection there.
Sand Boa: common questions
Are sand boas good pets for beginners?
The Kenyan sand boa is one of the best beginner snakes. It stays small, it is placid and rarely bites, it needs only a simple setup of a secure tank with a deep layer of aspen or a sand-and-soil mix to burrow in, a warm spot, and a water bowl, and it feeds readily. Its habit of staying buried with just its head out is part of the appeal, though it does mean the snake is often not on show. The main cautions are to avoid fine dusty substrate that can be inhaled, to use gentle handling since a startled sand boa may musk or nip, and to house them singly, as sand boas will sometimes try to eat a cagemate.
How does a sand boa catch its prey?
By ambush from under the surface. The snake works itself down into loose sand or soil, usually where it can sense rodent activity, leaving only its upward-facing eyes and nostrils clear. When a mouse or small bird passes within range, the boa erupts from the sand, seizes the animal, and throws coils around it, often dragging it down under the surface as it constricts, so the kill and the swallowing happen mostly out of sight. This buried-ambush style is why the snake has such small, high-set eyes and such a reinforced, wedge-shaped head.
Why is the female sand boa so much bigger than the male?
Sand boas show some of the strongest female-biased size difference of any snakes, with females of some species several times the mass of males. The usual explanation is that a bigger female can carry and nourish a larger or better-provisioned litter of live young, so selection favours large size in females, while males gain more from being small and mobile, able to search widely for mates and to move easily through the substrate. Small males may also mature faster. The result is that a breeding pair can look almost like two different animals.
Do sand boas actually need sand?
Not specifically sand, despite the name. What they need is a loose, dry substrate deep enough to burrow into and move through. In captivity keepers commonly use aspen shavings, or a mix of topsoil and play sand, rather than pure fine sand, which can be dusty and, if swallowed with prey, can cause a blockage. In the wild different sand boa species live in everything from true dune sand to gravelly desert to firm loess and farmland soil. The key requirements are that the ground is diggable and that it stays dry.