Javelin sand boa (Eryx jaculus)

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Javelin sand boa head profile

Top facts

  • The javelin sand boa typically hunts by lying in wait beneath sand or soil and ambushing passing prey.
  • The keeled scales of the javelin sand boa may help it to remain hidden under sand by preventing sand grains from sliding off its back.
  • Like many other boas, the javelin sand boa has rudimentary hind legs at the base of its tail.
  • Unlike most snakes, the javelin sand boa has been seen using its tongue to lap up water.
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Javelin sand boa fact file

Javelin sand boa description

KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyBoidae
GenusEryx (1)

The javelin sand boa (Eryx jaculus) is a relatively short snake with a thick, cylindrical body and a short, stubby tail (2). Like other sand boas (members of the genus Eryx), it is notable for its tendency to lie in ambush beneath the surface of the sandy areas it inhabits, springing upon prey from its hidden position (4) (5) (6).

As in other sand boas, the javelin sand boa’s head is small and not distinct from the neck, and its tiny eyes have vertical pupils (4) (7). Keeled scales and a furrow along the back may help sand boas to remain hidden in the sand, as the grains are unable to slide off the snake’s back (4).

The back of the javelin sand boa is sandy yellow to greyish or reddish-brown, with irregular dark blotches running along its length and giving rise to its alternative common name of ‘spotted sand boa’ (5) (6) (7) (8). The underside of the body is a paler whitish colour, usually without any markings (5) (7) (8). The javelin sand boa often has up to three short, dark stripes on the back of the neck, and a dark streak running from the eye to the corner of the mouth (7).

There are slight differences in appearance between the male and female javelin sand boa, with the female generally being longer than the male. In the female, the rudimentary hind legs that are present at the base of the tail are also usually larger than in the male (2).

Three subspecies of javelin sand boa are recognised: Eryx jaculus jaculus, Eryx jaculus turcicus and Eryx jaculus familiaris (1) (6) (9) (10).

Also known as
sand boa, spotted sand boa.
Synonyms
Anguis jaculus, Boa turcica, Eryx cerastes, Eryx familiaris, Eryx turcicus.
Size
Length: up to 84 cm (2)
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Javelin sand boa biology

Most active during twilight hours, the javelin sand boa usually lies hidden under sand or in cracks in the soil during the day and hunts at dusk and dawn (4) (5) (7). This species typically burrows through sand and soil (1) (4) (7), but when travelling on the surface it moves with a wave-like motion (5).

The javelin sand boa usually catches its prey by ambushing it, lying in wait under the sand or soil with the eyes and nose just above the surface to detect passing prey. When its victim comes close enough, the snake attacks it with surprising speed, and kills it by constriction (4) (6) (7). Small prey items may also be swallowed alive (4). The javelin sand boa is also thought to search actively for prey, for example by entering rodent burrows (2) (4) (11).

The diet of the javelin sand boa is thought to consist mainly of small mammals, as well as some lizards and birds (4) (7) (11), and occasionally invertebrates such as slugs (4) (6) (7). Unlike most snakes, the javelin sand boa has been observed using its tongue to lap up water (7). When threatened by a potential predator, the javelin sand boa may use its tail to deflect attention away from its vulnerable head region (4).

The javelin sand boa is ovoviviparous, giving birth to live young that have hatched from eggs within the female’s body (1) (2) (4) (7) (9). In captivity, Eryx species mate in the spring and early summer, with development of the young inside the female taking around four to five months (1) (4). The javelin sand boa usually gives birth to 5 to 20 offspring at a time (1) (2) (6), between August and September (1), with each of the young measuring about 14 to 20 centimetres in length and weighing around 8 grams (2).

Like other sand boas, the javelin sand boa is able to tolerate quite wide extremes of temperature and long periods of drought (4). This species becomes inactive between October and March or April (1), when it is likely to hibernate in loose sand, rodent burrows, crevices or beneath rocks (4).

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Javelin sand boa range

The javelin sand boa is found in northern Africa, from Morocco to Egypt, as well as in south-eastern Europe, the Middle East, Saudi Arabia, and east to Iran, Iraq and the Caucasus Mountains of Armenia, Azerbaijan, Georgia and southern Russia (1) (6) (7) (9) (10).

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Javelin sand boa habitat

The javelin sand boa typically prefers dry, sandy areas that are suitable for burrowing (5) (7), including open, dry steppes and semi-desert (1) (9). It is also frequently found in areas with soft soils, with a preference for clay and stony soils, and is sometimes found in agricultural areas, vineyards and gardens (1) (2) (9).

This snake has been recorded at elevations up to about 1,700 metres (1) (9).

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Javelin sand boa status

The javelin sand boa has not yet been globally assessed, but is classified as Least Concern (LC) on the IUCN European Red List (1), and is listed on Appendix II of CITES (3).

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Javelin sand boa threats

The javelin sand boa is not currently considered to be at risk of extinction in Europe due to its widespread distribution and apparently large population (1) (12). However, it is declining in many parts of its range, especially in western areas (1) (9) (12).

Habitat destruction is a major threat to the survival of the javelin sand boa. In much of its range, urbanisation, agricultural expansion and quarrying are reducing the available habitat, and this species is also affected by pesticide poisoning and pollution (1) (13). In addition, the javelin sand boa is popular in the pet trade (1) (8), and over-collection is often a problem, particularly in Egypt (1).

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Javelin sand boa conservation

The javelin sand boa is protected by law in some areas and is listed on the Red Data Books of a number of countries (9) (13). It is also listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that any international trade in the javelin sand boa should be carefully controlled (3).

In Europe, the javelin sand boa is listed on Appendix III of the Bern Convention (14) and on Annex IV of the EU Habitats Directive (15), which aim to protect European species and habitats. This small snake is found in many protected areas, but further research is needed into its populations and into the level of collection for the pet trade (1).

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Find out more

Find out more about the javelin sand boa and other reptiles:

More information on reptile conservation:

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Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

This species information was authored as part of the ARKive and Universities Scheme.
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Glossary

Genus
A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
Hibernate
Hibernation is a winter survival strategy in which the animal passes the winter in a resting state. This period of inactivity is characterised by specific biological and biochemical changes including lowered blood pressure and respiration rate. In reptiles, this is also known as brumation.
Invertebrates
Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
Keel
A projecting ridge along a flat or curved surface, particularly down the middle.
Ovoviviparous
Producing young that develop inside eggs, but the eggs hatch inside the female’s body and the young are born live.
Steppe
A vast grassland plain, characterised by few trees and low rainfall.
Subspecies
A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
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References

  1. IUCN European Red List (June, 2012)
    http://www.iucnredlist.org/initiatives/europe
  2. Schleich, H.H., Kästle, W. and Kabisch, K. (1995) Amphibians and Reptiles of North Africa. Koeltz Scientific Books, Koenigstein, Germany.
  3. CITES (June, 2012)
    http://www.cites.org/
  4. Lanza, B. and Nistri, A. (2005) Somali Boidae (genus Eryx Daudin 1803) and Pythonidae (genus Python Daudin 1803) (Reptilia Serpentes). Tropical Zoology, 18: 67-136.
  5. Baha El Din, S. (2006) A Guide to the Reptiles and Amphibians of Egypt. American University in Cairo Press, Cairo.
  6. O’Shea, M. (2007) Boas and Pythons of the World. New Holland Publishers, London.
  7. Boulenger, G.A. (1913) The Snakes of Europe. Arment Biological Press, Landisville, Pennsylvania. Available at:
    http://users.volja.net/housy/The_snakes_of_Europe.pdf
  8. Bartlett, R.D. (2005) Rosy, Rubber, and Sand Boas. Barron’s Educational Series, New York.
  9. Ananjeva, N.B., Orlov, N.L., Khalikov, R.G., Darevsky, I.S., Ryabov, S.A. and Barabanov, A.V. (2006) The Reptiles of Northern Eurasia. Pensoft Publishers, Sofia, Bulgaria.
  10. The Reptile Database (June, 2012)
    http://reptile-database.reptarium.cz/search.php
  11. Rodríguez-Robles, J.A., Bell, C.J. and Greene, H.W. (1999) Gape size and evolution of diet in snakes: feeding ecology of erycine boas. Journal of Zoology, 248: 49-58.
  12. Cox, N., Chanson, J. and Stuart, S. (2006) The Status and Distribution of Reptiles and Amphibians of the Mediterranean Basin. IUCN, Gland, Switzerland and Cambridge, UK. Available at:
    http://data.iucn.org/dbtw-wpd/edocs/2006-027.pdf
  13. Krecsák, L. and Iftime, A. (2006) A review of the records of the Sand boa (Eryx jaculus) in Romania. Herpetological Bulletin, 98: 31-34.
  14. Council of Europe: Bern Convention (June, 2012)
    http://conventions.coe.int/Treaty/EN/Treaties/Html/104.htm
  15. EU Habitats Directive (June, 2012)
    http://www.jncc.gov.uk/page-1374
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Javelin sand boa head profile  
Javelin sand boa head profile

© Kerstin Hinze / Biosphoto

Biosphoto
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http://www.biosphoto.com/

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