How to identify Gaboon Viper: Key physical features, range, habitat, and diet

If you've never heard of the Gaboon viper, you're not alone. It doesn't make headlines the way cobras or mambas do, but this African giant quietly holds some of the most jaw-dropping titles in the reptile world.

The Gaboon viper has the longest fangs of any venomous snake in the world, measuring as long as two inches. It is Africa’s largest viper and the world's largest “true viper,” belonging to the subfamily Viperinae, as opposed to pit vipers such as rattlesnakes.

There are two different species. In 1999, after analyzing mitochondrial DNA and discovering distinct genetic differences, scientists confirmed that the East African Gaboon viper and the West African Gaboon viper (Bitis rhinoceros) are separate species. The two look similar but differ in important ways. The West African species has large nasal horns and a single triangular marking between the eyes, while the East African species has smaller nasal horns and a marking that runs from the eyes towards the jaw. The West African species also gets larger, the largest recorded, from Sierra Leone, measuring over 81 inches, almost seven feet.

The species was first formally described in 1854 by the French zoologists Duméril, Bibron, and Duméril. Later, the species was moved into the genus Bitis, which was established in 1842 by the British zoologist John Edward Grey.

The master of hiding in plain sight
In Central, East and West Africa, from Nigeria and Cameroon to Kenya, Mozambique and the KwaZulu-Natal Province of South Africa, the Gaboon viper spends most of its time hidden on the forest floor. Its complex geometric pattern of browns, purples and creams is so convincing as leaf litter that you really have to look hard to see it, even if you know it’s there.

It prefers humid tropical forests, moist woodlands and forest edges, and is found near swamps, fallen logs, cashew plantations and forested escarpments; usually at low altitudes but sometimes as high as 1,500 m above sea level. It is not found in the Sahara and Namib deserts.

The Gaboon viper is mainly nocturnal and lives a slow, sedentary existence within a small home range. In the wet season, as more prey becomes available, their activity increases. It is an ambush predator, waiting patiently for rodents, hares, rabbits and birds to come within striking distance, then moving with startling speed, covering up to half its body length sideways in a single instant.

Docile, but don't push it
The Gaboon viper is known for its fearsome reputation, but it is actually docile, which is why there are very few human bites from it, according to a study in the journal Toxicon. When threatened, it will hiss loudly and raise its body as a warning, a deliberate show to discourage approach without resorting to a bite.

When the bite does happen, it is serious. The venom is mainly cytotoxic, killing tissue, but also has hemotoxins that dissolve fibrinogen and inhibit clotting of blood, and cardiotoxins that attack the heart.

Due to their size and camouflage, adult Gaboon vipers have few natural predators, but large birds of prey, monitor lizards, mongooses and honey badgers will occasionally eat juveniles.

The dramatic path to parenthood
Mating generally takes place from September to December. Males engage in a ritual fight, raising their heads, wrapping their bodies together, and trying to pin each other down. The winner mates with the female. Females give birth after a gestation period of between seven months and a year, and up to 60 offspring may be born at a time, although 30 to 40 is more typical. The young are utterly independent from the moment they are born.

The venom-to-medicine pipeline
Here is where the Gaboon viper’s tale resonates with American healthcare. Snake venoms are becoming increasingly recognized as a source of compounds with the potential to treat serious conditions.

The therapeutic potential of snake venom-based compounds has already been demonstrated by FDA-approved drugs such as Captopril and Aggrastat (Tirofiban), and more compounds are currently being studied in clinical trials for thrombolytic and antithrombotic activities, as reported in a systematic review published on PubMed Central. As reviewed in ScienceDirect, Eptifibatide and Tirofiban are two FDA-approved drugs that are currently used for the treatment of acute coronary syndrome and were developed directly from disintegrins found in snake venoms. The experimental antiplatelet drug Anfibatide, derived from pit viper venom, is also being investigated for its ability to inhibit platelet adhesion and aggregation.

The Gaboon viper’s venom itself, rich in metalloproteinases, phospholipases and thrombin-like enzymes, continues to be of scientific interest for future studies.

A species quietly under threat
The Gaboon viper’s forest habitat is slowly disappearing in Africa due to deforestation. Illegal wildlife trade is a serious additional threat in Zimbabwe, where its range is already limited. Chipangali Wildlife Orphanage in Zimbabwe is also helping to preserve the country’s population through a conservation breeding program.

For a snake this extraordinary, record-breaking, near-invisible, and scientifically valuable, it deserves far more attention than it gets.