By Jacqueline Howard
Geographic Range
Gaboon vipers are found throughout sub-Saharan Africa. (FitzSimons, 1970; Isemonger, 1962)
Habitat
Gaboon vipers are abundant in rainforests and other moist, tropical habitats. They tend to take shelter in the leaf litter of forest floors. (FitzSimons, 1970; Isemonger, 1962)
These animals are found in the following types of habitat:
tropical
; terrestrial
.
Terrestrial Biomes:
rainforest
.
Physical Description
(15.4 to 22 lbs; avg. 18.7 lbs)
(7.22 ft; avg. 3.94 ft)
Gaboon vipers are large snakes, the largest of the vipers, with an average adult length of about 1.2 meters. However, some have been recorded as large as 2.2 m long or greater. They can weigh up 10 kg with a head about 12.7 cm wide and fangs about 5 cm long. Gaboon vipers have triangular heads with prominent rostral horns. There is also a very dark line down the center of the head and two dark spots above each side of the jaw. The scales are ridged and keeled on the majority of the body, however there are a few rows of scales on the lowest part of both sides that are smooth. There are 28 to 40 rows of scales in the middle part of the body, an average of 125 to 140 rows on the ventral side. Males and females differ in the number of scales they have (females having less than 135 rows and males having less than 132 rows). Color patterns of gaboon vipers are truly stunning, forming a symmetrical design that makes a unique pattern on the scales. The base color is typically a brown or purple color. On top of that are yellow, quadrangular shapes, that are aligned neatly over the center of the back. These shapes have hourglass brown spaces, and along the sides of the body are triangular patterns, which are the brown or purple coloring and in between the series of triangles are yellow and purple stains. The ventral side is a light yellow color with dark spots sprinkled throughout. This camouflage pattern is adaptive in helping gaboon vipers blend into their surroundings. Their eyes are grayish with a hint of silver. (Cansdale, 1961; FitzSimons, 1970; Isemonger, 1962; Krutein and US Copyright Law, the Berne Convention 1979)
Some key physical features:
ectothermic
; bilateral symmetry
; venomous
.
Sexual dimorphism:
female larger.
Development
Gaboon vipers are viviparous, with a 7 month gestation period. They give birth to about 30 or more offspring at once. (FitzSimons, 1970)
Reproduction
September - December
Observations of gaboon vipers kept in captivity have lead to some information about their mating systems. Gaboon vipers generally mate in the rainy season, so spraying water on the vipers in captivity helps to mimic the rainy season. The female will then get restless and lift her tail, showing the male that she is ready to mate. They may sway back and forth as well. (Dexter, VenomousReptiles.org 2000 - 2005)
Gaboon vipers mate during the rainy season in Africa, which is between September and December. The gaboon viper is viviparous, with a 7 month gestation period, and gives birth to about 30 or 40 offspring at once. (Dexter, VenomousReptiles.org 2000 - 2005; Fitch, 1970)
Key reproductive features:
gonochoric/gonochoristic/dioecious (sexes separate); viviparous
.
When the offspring are born, they are already as big as 30 cm long and already have adult-looking patterns on their scales. There is no real parental care once the offspring are born. (FitzSimons, 1970)
Parental investment:
no parental involvement; pre-fertilization (provisioning, protecting: female).
Lifespan/Longevity
There is no information on the longevity of gaboon vipers.
Behavior
Gaboon vipers are nocturnal and solitary. They are most active around sunset, when they emerge from a dark hiding place in search of prey. They generally lie perfectly still, blending in with the leaves of the forest floor, waiting for prey to cross their path. (Isemonger, 1962; Krutein and US Copyright Law, the Berne Convention 1979)
Communication and Perception
Gaboon vipers, like other vipers, detect vibrations, chemical signals, and visual cues. Using all to detect and attack prey. There is nothing known about how gaboon vipers communicate, but they may use chemical cues to to locate receptive mates.
Communicates with:
chemical
.
Perception channels:
visual
; vibrations
; chemical
.
Food Habits
Gaboon vipers await their prey from a hiding spot and quickly attack with 5 cm fangs, injecting toxic venom into the tissues of the prey. They eat primarily small mammals, such as rodents, ground-living or feeding birds (such as francolins or doves), and frogs and toads. Specimens of gaboon vipers have been found to have ingested giant rats (Cricetomys gambianus), brush-tailed porcupines (Atherurus africanus), and fully grown royal antelopes (Neotragus pygmaeus). (Cansdale, 1961; FitzSimons, 1970; Isemonger, 1962)
Primary Diet:
carnivore
(eats terrestrial vertebrates).
Animal Foods:
birds; mammals; amphibians; reptiles.
Predation
There are no known predators of gaboon vipers. They are cryptically colored, blending in well with leaf litter on the forest floor, perhaps to hide from potential prey.
Anti-predator adaptations::
cryptic
.
Ecosystem Roles
As a predator of small mammals, gaboon vipers help to control rodent populations. (Kayembe, WhoZoo Project 1998-2005)
Economic Importance for Humans: Negative
Gaboon vipers can directly harm humans if disturbed but they are not generally aggressive if left alone. When disturbed, gaboon vipers will either sound a loud hiss or deliver a venomous bite. Many humans have died from gaboon viper bites. Survivors have often had to have affected limbs amputated. Their deadly venom contains neurotoxin and hemotoxin, which destroys the blood cells and vessels. (Isemonger, 1962; Kayembe, WhoZoo Project 1998-2005)
Ways that these animals might be a problem for humans:
injures humans (bites or stings, venomous
).
Economic Importance for Humans: Positive
Gaboon viper venom is not known to have any medical uses, but further research is necessary.
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Gaboon vipers are not currently considered threatened. (Kayembe, WhoZoo Project 1998-2005)
For More Information
Find Bitis gabonica information at
Contributors
Tanya Dewey (editor), Animal Diversity Web, University of Michigan Museum of Zoology.
Jacqueline Howard (author), Kalamazoo College. Ann Fraser (editor, instructor), Kalamazoo College.

