Common names: Mount Kenya bush viper, Ashe's bush viper, Desaix's bush viper.

Atheris desaixi is a venomous

Venomous snake

"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...

 viper

Viperinae

The Viperinae, or viperines, are a subfamily of venomous vipers found in Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the Crotalinae. Currently, 12 genera and 66 species are recognized...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 endemic to Kenya, where only two isolated populations are known. It is known for its striking black and yellow coloration. This species is named in honor of a Peace Corps

Peace Corps

The Peace Corps is an American volunteer program run by the United States Government, as well as a government agency of the same name. The mission of the Peace Corps includes three goals: providing technical assistance, helping people outside the United States to understand US culture, and helping...

 volunteer who collected the first specimen: Mr. Frank DeSaix. No subspecies are currently recognized.

Description

Adults are an average 40-60 cm in length, with a maximum of 70 cm. Newborns measure 17-22 cm. In Ashe's original 1968 description, adults were reported to grow to an average 49-68 cm total length, with a head and body length of 43-59 cm and a tail length of 6-9 cm.

The eyes are set well forward in the head and are surrounded by 14-17 scales. Interorbital scales

Interorbital scales

In snakes, the interorbital scales, or intersupraoculars, are the scales on the top of the head between the plates surmounting the eyes ....

 number 8-11. The eye is separated from the nasal by two to three scales and from the supralabials by two. Upper labials: 10-12. Sublabials: 11-14. The rostral scale is not as wide as it is long, while its upper margin is highest at the center. The rostral is also accompanied by an even number of suprarostrals. The superciliary scales above the eyes are not enlarged (as opposed to A. ceratophora

Atheris ceratophora

Atheris ceratophora is a venomous viper species found only in a few mountain ranges in Tanzania. This is the only horned, arboreal viper in Africa. No subspecies are currently recognized.-Description:...

). The nasal scale is round and single, or partially divided.

Midbody, the dorsal scale rows number 24-31, are short and heavily keeled. However, on the upper dorsals the keels terminate before the end of each scale. On the lower dorsals, the keels are serrated (like in Echis

Echis

Echis is a genus of venomous vipers found in the dry regions of Africa, the Middle East, Pakistan, India and Sri Lanka. They have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound...

). The ventral scale count is 160-174. In females the subcaudals number 41-54. One male specimen had 53 subcaudals.

The color-pattern consists of a greenish-black to charcoal black ground color, while each scale is tipped with yellow or yellowish-green, giving the animal a speckled appearance. Some scales have more of this color to them and form a series of loops along the sides of the body. These loops may fuse into zigzag patterns posteriorly, fading again on the tail. Anteriorly, the venter is yellow or yellowish, fading towards a purplish-black towards the rear and under the tail, except for the tip that is blotched with yellow. Juveniles are mainly yellow with a white tipped tail. This darkens as they grow until they reach the adult color phase at a length of about 30 cm.

Geographic range

Two isolated populations in Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

: in the forests at Chuka, south-eastern Mount Kenya

Mount Kenya

Mount Kenya is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian , Nelion and Point Lenana . Mount Kenya is located in central Kenya, just south of the equator, around north-northeast of the capital Nairobi...

, and Igembe in the northern Nyambeni range. The type locality is listed as "near Chuka, Lat. 0°20'S, Long. 37°35'E, in rain forest at an altitude of c. 1600 meter," Kenya.

Conservation status

Currently, this species is not listed on the IUCN Red List of Threatened Species nor in any of the CITES Appendices. In 2004, a proposal was submitted by Kenya

Kenya

Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...

 to have it listed in CITES Appendix II on the grounds that the species has a very limited geographic range and suffers from rapid habitat loss. It is also threatened by illegal trade due to demand from reptile collectors in Europe and North America. Apparently this proposal was not accepted. The Commission of European Communities considered the arguments weak, saying that they did not demonstrate significant trade, and that the species is already protected in Kenya. They suggested Appendix III instead.

Habitat

The original specimens, for which field notes were taken, were found in dense rain forest at 1600 m, collected in clearings and along pathways in the dense foliage about 2 m above the ground. The conditions were very humid and all specimens were collected within a 1.6 km radius. In this environment, their coloration offers them an excellent camouflage, making them very difficult to spot.

Behavior

Little is known. They are obviously arboreal, moving slowly and deliberately among the branches of their habitat as other Atheris

Atheris

Atheris is a genus of venomous vipers found only in tropical subsaharan Africa, excluding southern Africa. Confined to rain forest areas, many members have isolated and fragmented distributions. In an interesting example of convergent evolution, they show many similarities to the arboreal pit...

 species do, but it is unknown when their daily peak activity occurs. In captivity, they are just as willing to accept food during the day as at night.

When captured, they will strike readily and struggle vigorously in the hand. They may also perform a characteristic, stridulating

Stridulation

Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fishes, snakes and spiders...

 threat display, in which counterlooped coils and the lower serrated, keeled scales are rubbed against one another to produce a loud hissing noise. However, captive specimens soon calm down and this behavior is lost.

Reproduction

A gravid female specimen found in the Nyambeni range is reported to have given birth to 13 offspring in the month of August. Newborns measured 17-21 cm in length.

Venom

The Kenyan who collected the first specimens was bitten by an adult, with a single fang penetrating his right index finger. There was significant swelling and pain. A tourniquet was applied and an unknown antivenin

Antivenin

Antivenom is a biological product used in the treatment of venomous bites or stings. Antivenom is created by milking venom from the desired snake, spider or insect. The venom is then diluted and injected into a horse, sheep or goat...

was administered, after which the patient made a full recovery. It is doubtful, however, that the antivenin made any difference in this case, for no antivenin is known to be effective. Nevertheless, since these snakes are relatively large (for Atheris) and their venom is known to contain powerful anticoagulants, a bite should be taken seriously. Poor coagulation may even require blood transfusions.

External links

• CoP13, Prop. 30 at CITES. Accessed 8 October 2006.
• The Jacksonville Florida Zoological Gardens Herps at Awesome Arboreals. Accessed 9 October 2006.
• Mount Kenya bush viper (Atheris desaixi), Kenya at Dr. Zoltan Takacs Homebase. Accessed 9 October 2006.