Reptiles
Mussurana
Clelia clelia · also called mussurana, musurana, black cribo
The mussurana is a large, glossy, blue-black snake of Latin America with an unusual job: it hunts and eats the region’s most dangerous vipers. It grabs a fer-de-lance, throws coils around it, and constricts it to death, shrugging off the bites it takes in the process — and because of this, farmers across Central and South America go out of their way to protect it.
Overview
The mussurana ranges from southern Mexico to northern Argentina, in rainforest, gallery forest, savanna, grassland, and farmland. It reaches 1.6–2.4 m, heavy-bodied. Juveniles are bright coral-red with a black head, resembling a coral snake; adults are uniform iridescent blue-black.
A snake that eats snakes
The mussurana is a specialist predator of other snakes, especially pit vipers like the fer-de-lance. It seizes a viper in its jaws, wraps it in coils, and kills it by constriction, sometimes swallowing prey longer than itself. Its blood neutralises pit-viper venom, so the bites it takes during the struggle do it little harm.
Almost harmless to people
It has a weak venom delivered by grooved back teeth, used to subdue prey. Bites to humans are rare and cause only minor local effects, and the snake is calm and slow to bite.
A protected snake
Because it cuts down numbers of the fer-de-lance, which causes many serious snakebites in rural Latin America, the mussurana is valued and deliberately protected around farms and homes, and appears in folklore as a good snake.
Status
The mussurana is Least Concern, widespread, common, and tolerant of farmland.
Mussurana: common questions
Does the mussurana really eat venomous snakes?
Yes, and pit vipers are its favourite food. The mussurana actively hunts snakes such as the fer-de-lance and its relatives, which are among the most dangerous snakes to people in Latin America. It grabs the viper in its jaws, often behind the head, wraps it in coils, and kills it by constriction, the same method a boa uses on a rodent. During the fight the viper frequently bites the mussurana, but the mussurana's blood contains substances that neutralise pit-viper venom, so those bites usually do little harm. A large mussurana can swallow a viper longer than its own body.
Is the mussurana dangerous to humans?
Barely. It does have venom, delivered through enlarged grooved teeth at the back of its mouth, but the venom is weak and adapted to subduing cold-blooded prey, and the rear-fanged delivery is inefficient against a large animal. Bites to people are uncommon, usually happen only when a snake is handled or trodden on, and typically cause nothing more than local pain, swelling, and mild bleeding from the tooth punctures. The mussurana is generally calm and slow to bite, and in the places where it lives it is regarded as one of the safe snakes.
Why do people in Latin America protect the mussurana?
Because it kills the snakes that hurt them. The fer-de-lance and other Bothrops vipers are responsible for a large share of the serious and fatal snakebites across Central and South America, particularly among farm workers. A snake that hunts and eats those vipers, and that is itself almost harmless to people, is a genuine asset around a farm or a village. In many rural areas the mussurana is well known, is left alone or even encouraged, appears in folk stories as a protective or lucky snake, and has been the subject of programmes to breed and release it or to educate people not to kill it.
Why are baby mussuranas red and black?
Young mussuranas have a bright coral-red body, a black head, and a light band across the neck, a pattern that closely resembles the venomous coral snakes that share their range. This is generally interpreted as mimicry — a small, vulnerable snake gains protection from predators that have learned to avoid the deadly coral snake colour scheme. As the mussurana grows large enough that few predators would tackle it anyway, the bright pattern is lost, and the snake darkens to the plain iridescent blue-black of the adult.