They belong to the family of snakes Boidae, which contains some of the world's largest snakes. These, include pythons, boas, and anacondas such as the massive Green Anaconda (Eunectes murinus).
These boas are widespread in the south and southwest of the island, occupying semi-arid habitats, with a relatively low amount of rainfall.
They are found in both intact and disturbed forest and thorn bush at lower elevations and in savannas on the central highlands of Madagascar. The Dumeril's boa can also be found in human modified and disturbed habitats such as eucalyptus forests and villages.
The Dumeril's boa grows to about 4 to 6 feet (1.2 / 1.8 m) in total length which includes the tail. But the species maximum length is around 7 feet (210 cm). They typically weigh less than 20 pounds (9 kg) and while males normally have a longer and skinnier tail, females are usually larger overall.
Their color pattern consists of a grayish-brown ground color covered with darker patches, the head has brown “bridle” stripes that help to break up the snake’s outline. In some individuals, there's a large amount of a pinkish or coppery coloration.
Their cryptic pattern helps them to blend in with the dry leaf litter of the forest floor, effectively hiding them from both prey and predators.Their estimated lifespan is about 20 to 30 years in the wild.
Although their trade is nowadays heavily restricted, the Dumeril's boa is quite prolific in captivity. This makes the species very easy to find in the exotic pet trade and captive specimens are also relatively cheap.
The Dumeril’s boa makes a great pet snake, they usually have a calm disposition and rarely attempt to bite, but probably aren't recommended as the very first pet snake.
Subspecies / Taxonomy / Etymology
The species was first described in 1860 by Giorgio Jan, an Italian taxonomist, zoologist and botanist. There are no subspecies are currently recognized by scientists.
The genus "Acrantophis" derives from the Greek words “akrantos” meaning useless or lazy combined with "ophis" which translates to snake. This name was probably a result of the species being found in a state of no activity or very low activity.
The Dumeril's boa species specific name, dumerili, was given in honor of French herpetologist André Duméril.
Diet / Feeding
The Dumeril's boa is like all snakes is a carnivore, these large snakes kill their prey by constriction. In the wild, they feed on small wild animals such as mammals in particular rodents, birds, and lizards and are also known to sometimes prey on other snakes.
They will also take domestic poultry like chickens, which often results in these snakes being killed by humans. They are able to wait in ambush for long periods of time before striking at prey passing nearby.
Like all snakes they don't need to feed as frequently as mammals, usually only eating once a week and during the cooler winter months may not eat at all. Captive specimens are fed mice as juveniles while adult snakes eat rats and rabbits.
Unlike pythons such as the Burmese python (Python bivittatus), the Dumeril's boa is an ovoviviparous species, meaning these snakes don't lay eggs they give birth to live baby snakes.
In the wild the mating season is in the spring, running from March through May after a short brumation period, a process similar to the mammalian hibernation.
During this time males will sometimes fight and even injure each other in order to gain access to receptive females.
The males have anal spurs, used to stimulate the female during courtship. After a gestation period of about 6 to 8 months, the eggs hatch inside of the female’s body, resulting in the live birth of the babies.
The litter normally consists of 6 to 13 juveniles but sometimes a litter can be over 20 babies. Since Madagascar has few large predator species the Dumeril's boa has small litters when compared to other boa species like the Boa constrictor which may give birth to 60 or more babies.
The young snakes are quite large about 12 to 18 inches long (30 to 46 cm) and are independent from birth. They also grow very rapidly, becoming big enough to avoid being hunted by smaller predators.
These boas reach sexual maturity at about 3 to 5 years of age, although males usually reach it at younger ages.
Conservation / Threats
In the mid-nineties the Dumeril's Boa was classified as a vulnerable species, but, it has since been reclassified as Least Concern species on the IUCN Red List (2011).
They are also listed on CITES Appendix I, meaning that international trade is prohibited for commercial use, with some non-commercial exceptions like specimens for scientific research.
Even so, the Duméril's Boa is still collected for the international pet trade, albeit in much lower numbers than in the past. It's also used in reduces numbers for the leather trade and as food by Chinese communities.
Although it faces no significant threats, it is affected by deforestation and also human persecution. But this is a very adaptable species and is still widespread throughout the south and southwest of Madagascar.
The species current population trend is considered stable and they are also found in most of the protected areas within its range. These snakes are often killed on sight, by people since they are perceived as bringing bad luck and also a potential predator for domestic chickens.
Did You Know?
The hibernation period for snakes is called brumation, find more snake facts for kids.