The Ethiopian mountain adder, also known as the Ethiopian viper, is a venomous snake found only in the highlands of Ethiopia. Scientifically known as Bitis parviocula, this viper species is endemic to Ethiopia.
Ethiopian Highlands, the natural habitat of the Ethiopian Mountain Viper.
Little is known about the endangered species, but we do know that they are viviparous, meaning that they give birth to live young rather than laying eggs.
Physical Characteristics
These snakes are heavy bodied with distinctive highly contrasting black and yellow patterns that help with camouflage. It is large with a broad head and spectacular geometric markings. The head is long, flat, triangular and covered with small, strongly keeled scales. The nostrils are large and set well forward. The head is distinct from the thin neck. The body is cylindrical with a slight vertebral ridge, while the tail is short.
The color pattern consists of a light brown to dark brown ground color, overlaid with a series of black hexagons or diamonds that run down the center of the back. The black hexagons may have paler crossbars, while being separated from each other by a chain of yellow butterfly shapes. A series of black triangular or subtriangular spots, each with a white center, run down the upper flanks. The lower flanks have a series of greenish-gray triangles, pointing upwards, with yellow edges, especially the tips. The flanks between these triangles are a mottled green color.
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The head is brown with a dark triangle between the eyes and a dark hammer shape just behind it that extends onto the nape of the neck. The iris is brown. The side of the head is dark, but with a pale stripe that runs from the eye down to the labials. The upper labial scales are white. The chin and throat are white with black speckling.
Size and Growth
Of the first three specimens, the maximum recorded total length (body + tail) was 75.2 cm (29.6 in), but it is now known to reach a total length of at least 130 cm (51 in).
Habitat and Distribution
Known from only five localities in Ethiopia, it is found on both sides of the Rift Valley, both in the Bale Mountains to the east and between Bonga and Jimma to the west. The type locality is given as "Doki River bridge (8°20′N 35°56′E / 8.333°N 35.933°E / 8.333; 35.933), bei Yambo (=Yembo), an der Straße von Metu nach Bedelle, Provinz Illubabor, SW-Äthiopien ".
Of the three specimens known in 1995, two were found in forested areas west of the Rift Valley and one was found in grassland to the east. Of the two western specimens, one was caught in a forest clearing in an old coffee plantation, while the other was found in a forest town, hiding in grass of the grounds of a brewery.
Behavior and Temperament
Mostly unknown, its behavior is assumed to be terrestrial and nocturnal. In 1995, the only living specimen known was less irritable than the typical puff adder (B. arietans) and was not inclined to strike. However, it hissed when teased and struggled "furiously" when restrained, suggesting its temperament may be similar to that of the Gaboon viper (B. gabonica).
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Venom and Bites
Until recently, the toxicity and composition of the venom essentially was unknown. It is assumed to cause at least some of the bites reported in the densely populated regions where it occurs. The local people consider it very dangerous.
The first US envenomation of a person was in March 2009 when a herpetologist from Texas was bitten in the finger by a young, captive B. parviocula, which he survived. It is the only well-documented bite report of this snake.
Ethiopian mountain viper (Bitis parviocula)
Conservation Status and Threats
Ethiopian mountain adders are found at elevations suited to growing coffee so they’re threatened by habitat loss to support that industry. Climate change could also impact this species.
Agricultural expansion and logging continue to reduce the quality and extent of the species’ only known habitat in the wild.
Coffee plantations, a major threat to the habitat of the Ethiopian Mountain Viper.
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Conservation Efforts
The species has been identified as an EDGE reptile. This means we recognise that the Ethiopian mountain adder is unique, extraordinary, overlooked, under threat, and in great need of being protected.
At London Zoo, we achieved the first EAZA breeding of this snake in 2021 and coordinate the EAZA Ex situ Programme (EEP) for the species, with the aim of maintaining healthy and thriving populations of the animals within EAZA and beyond.
We have supported several student projects looking at the species' ecology and traits. We have also trained an EDGE Fellow working on a related species in Kenya how to do this too, demonstrating how tools developed in our zoos can be directly applicable to monitoring and conserving threatened species in situ.
About the Genus Bitis
Bitis is a group of venomous viper snakes. You can find them in Africa and the southern Arabian Peninsula. This group includes some of the biggest and smallest vipers in the world. There are currently 14 known types, or species, of Bitis snakes. The Bitis group is special because it has both the largest and smallest vipers on Earth.
- The biggest viper is the Gaboon Viper. It can grow up to 2 meters (about 6.5 feet) long!
- On the other hand, the smallest viper is the Namaqua Dwarf Adder.
Common Traits of African Adders
All African Adders have a few things in common. They usually have wide, triangle-shaped heads. Their snouts are often large and rounded. These interesting snakes live in two main areas. You can find them across much of Africa. African Adders mostly live on the ground. This means they are "terrestrial." They like to wait quietly for their food to come by. Even though they can seem slow, they can bite very quickly.
If something bothers them, African Adders often puff up their bodies. They also make a loud hissing sound to warn others. All African Adders give birth to live young.
Diet
These snakes eat many different small animals. Their diet includes small rodents like mice and rats. They also eat birds and amphibians. This means they might eat frogs and toads.
List of Bitis Species
Here is a list of some of the Bitis species:
- Puff Adder, B. arietans
- Berg Adder, B. atropos
- Horned Adder, B. caudalis
- Many-horned Adder, B. cornuta
- Gaboon Viper, B. gabonica
- Angolan Adder, B. heraldica
- Plain Mountain Adder, B. inornata
- Rhinoceros Viper, B. nasicornis
- Ethiopian Mountain Adder, B. parviocula
- Peringuey's Desert Adder, B. peringueyi
- Red Adder, B. rubida
- Namaqua Dwarf Adder, B. schneideri
- Kenya Horned Viper, B. worthingtoni
- Desert Mountain Adder, B. xeropaga
Bitis species are known for their behavior of inflating and deflating their bodies in loud hissing or puffing threat displays.
All members of this genus are dangerous- some extremely so. At least six different polyvalent antivenoms are available.
The Ethiopian Mountain Viper remains an elusive and fascinating species, highlighting the rich biodiversity of Ethiopia and the importance of conservation efforts.
