Kenyan Sand Boa

About the Kenyan sand boa

The Kenyan sand boa is one of several common names for Eryx colubrinus, a species of snake in the subfamily Erycinae within the boa family, Boidae. It also goes by East African sand boa, Egyptian sand boa, Kenya sand boa, and simply sand boa. The species is native to northern and eastern Africa, and three subspecies are recognized: the nominate form, along with E. c. loveridgei and E. c. rufescens.

The nominate subspecies was originally described under the genus name Anguis, given by Linnaeus, with a type locality recorded simply as "Ægypto," Egypt. When the additional subspecies are recognized, E. c. loveridgei occurs in the southern part of the overall range and tends to run more orange in color, while E. c. rufescens is smaller and more rounded than E. c. loveridgei, with rougher scales. Some herpetologists have questioned whether these forms are distinct enough to warrant separate subspecies status, or whether the species is better understood as a single, geographically variable population; the subspecies name loveridgei itself honors British herpetologist Arthur Loveridge.

Physically, the Kenyan sand boa is a heavily built snake with a small head, small eyes with vertical pupils, and a short tail. Its scales are smooth over most of the body, but the tail tapers into a keeled scale pattern. Adult females are rarely more than 91 cm (3 ft) in total length, and the average animal grows no longer than about 12 to 32 in (30 to 80 cm), with males significantly smaller than females. Coloration is typically yellow or orange overlaid with dark brown splotches, and the belly is white or cream. Because of its small size, docile temperament, and easy care, the species is widely available in the pet trade, and breeders have developed numerous color morphs, including anerythristic, albino, and the double-recessive "snow" combination, along with striped, hypo, paradox, splash, and paint varieties, and further line-bred traits such as extreme-red "nuclear" and high-white patterns.

Taxonomically, a synonym for the species is Anguis colubrina, the name given by Linnaeus. Researchers in 1969 recognized two subspecies, though earlier authors had questioned whether the second was distinct or whether the species was better treated as a single, geographically variable population. A 2023 study proposed that Eryx colubrinus is the closest living relative of a Miocene fossil species from Gansu, China, suggesting the genus dispersed repeatedly from Africa to Eurasia during that period.

Behavior and diet

The Kenyan sand boa is most active at night, though it may move irregularly during the day as well. It is a fossorial species, meaning it lives largely underground, spending roughly 80 percent of its time buried. During the hottest parts of the year it takes shelter beneath stones and in the burrows of small mammals, though it has also been recorded occasionally climbing trees.

As a predator, the Kenyan sand boa feeds on small mammals such as rodents, along with lizards and birds. It hunts by ambush, hiding beneath the sand and waiting for prey to come within striking range before killing it by constriction. It has also occasionally been known to seek out the nests of small mammals and birds rather than waiting for prey to pass.

Reproduction is ovoviviparous, meaning the young develop inside eggs that hatch within the mother, resulting in live birth. In captivity in the United States, the species breeds readily from November through April, and litters average 10 to 20 babies, delivered from spring through late summer. At birth, young typically measure 20 to 25 cm (8 to 10 in) in length.

Range and habitat

The Kenyan sand boa is found across North Africa, from Egypt west to Niger, and includes Somalia, Ethiopia, Sudan, Kenya, and northern Tanzania. A single specimen has also been reported from Yemen. Within this area, it occupies semi-desert and scrub savanna, as well as rocky outcroppings, and it prefers sandy, friable soil that supports its burrowing lifestyle.

Conservation status

The Kenyan sand boa (Eryx colubrinus) is listed as Least Concern on the IUCN Red List, in a 2021 assessment. Its range is wide, stretching across the semi-desert and scrub savanna of northern and eastern Africa from Egypt and Niger to Kenya and northern Tanzania.