Southern adder (Bitis armata)

Description

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Southern adder fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Southern adder description

This small viper has distinctively raised, protruding scales above each eye and a broad, triangular head, typical of viperids ⁽⁴⁾. The body is greyish-brown with rows of darker, reddish-brown blotches running down its length, more conspicuous above and paler on the sides, between which there may be a series of contrasting pale patches. This partially arboreal adder possesses a distinctly prehensile tail ⁽⁵⁾.

Synonyms

Bitis cornuta.

Size

Male length: up to 330 mm ⁽²⁾

Female length: up to 374 mm ⁽²⁾

Southern adder biology

An ongoing study of the southern adder that began in 2004 has located 18 specimens to date and revealed some important information on the species’ biology and behaviour ⁽⁶⁾. Unlike other members of the Bitis cornuta - inornata species complex, the southern adder is partially arboreal, having been recorded climbing up to heights of two metres ⁽⁵⁾. The adder appears to feed on lizards, but will also take small rodents ⁽⁷⁾. The study has also shown that individual snakes tend not to travel any great distance, but prefer to stay within a limited area, a behaviour that may prove significant to the snake’s long-term conservation ⁽⁸⁾.

Bitis species are all believed to be ovoviviparous, giving birth to live young ⁽⁴⁾.

Southern adder range

Found in South Africa, with two geographically separated populations known from the West Coast National Park and the DeHoop Nature Reserve ⁽⁶⁾.

Southern adder habitat

The southern adder does not occur above 300 metres above sea level, and is essentially a coastal species ⁽⁶⁾.

Southern adder status

This species has not yet been classified by the IUCN. The southern adder belongs to the Bitis cornuta-inornata species complex, an enigmatic group of rare dwarf adders consisting of five similar species whose taxonomy has only recently been revised ⁽³⁾.

Southern adder threats

All five species belonging to the Bitis cornuta-inornata complex are vulnerable to habitat loss as a result of development and wild fires, and also illegal collecting for the pet trade. The southern adder, in particular, has suffered heavily from coastal development, which has resulted in massive habitat loss for this species ⁽⁶⁾.

Southern adder conservation

Fortunately, the two populations of the southern adder found in the West Coast National Park and the DeHoop Nature Reserve have a relatively safe refuge. The species has been studied at the DeHoop Nature Reserve since September 2004 by Squamate Ecologist Dr. Tony Phelps of the Cape Reptile Institute. Prior to this, no southern adders had been recorded since 1992. The study is ongoing, and it is hoped that findings on population structure, spatial distribution and biology will provide important insight into the status of these little known adders, which will in turn aid management and future conservation measures ⁽⁶⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

Authentication

Authenticated (11/07/2006) by Dr. Tony Phelps, Squamate Ecologist and founder of the Cape Reptile Institute.
http://www.crepinstitute.co.za/

Glossary

Arboreal

An animal which lives or spends a large amount of time in trees.

Ovovivipary

Method of reproduction whereby the egg shell is weakly formed and young hatch inside the female; they are nourished by their yolk sac and then ‘born’ live.

Prehensile

Capable of grasping.

Species complex

A group of closely related species that satisfy the scientific definition of species - that is, they are reproductively isolated from each other - but which are anatomically very similar. The individual species within the complex can often only be separated using methods from molecular genetics such as DNA barcoding.

References

1. UNEP-WCMC (May, 2006)
   http://www.unep-wcmc.org
2. Sean Thomas (July, 2006)
   http://www.seanthomas.net/oldsite/slength.html
3. Branch, W.R. (1999) Dwarf adders of the Bitis cornuta-inornata complex (Serpentes:Viperidae) in South Africa. Kaupia, 8: 39 - 63.
4. The TIGR Reptile Database (June, 2008)
   http://www.tigr.org/reptiles/families/Viperidae.html
5. Phelps, T. (2006) Bitis armata (Smith, 1826). Southern Adder. Arboreal Behaviour. Afr, Herp. News, 39: 14 - 16.
6. Phelps, T. (2006) Pers. comm.
7. Phelps, T. (2006) Bitis armata (Smith 1826). Southern Adder. Prey Items. Afr. Herp. News, 40: 26 - .
8. Phelps, T. (2006) Bitis armata (Smith 1826). Southern Adder. Sedentary Behaviour. Afr. Herp. News, 40: 25 - .