Cerastes cerastes

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Cerastes cerastes, commonly known as the Saharan horned viper<ref name="Mal03">Mallow D, Ludwig D, Nilson G. (2003). True Vipers: Natural History and Toxinology of Old World Vipers. Malabar, Florida: Krieger Publishing Company. Template:ISBN.</ref> or the desert horned viper,<ref name="Meh87">Mehrtens JM. (1987). Living Snakes of the World in Color. New York: Sterling Publishers. Template:ISBN.</ref> is a species of viper native to the deserts of Northern Africa and parts of the Arabian Peninsula and Levant. It is often easily recognized by the presence of a pair of supraocular "horns", although hornless individuals do occur.<ref name="Mal03"/> Three subspecies have been described.

Description

The average total length (body and tail) is Template:Convert, with a maximum total length of Template:Convert. Females are larger than males.<ref name="Mal03" />

One of the most distinctive characteristics of this species is the presence of supraorbital "horns", one over each eye. However, these may be reduced in size or absent (see genus Cerastes).<ref name="Mal03"/> The eyes are prominent and set on the sides of the head.<ref name="SB95"/> There is significant sexual dimorphism, with males having larger heads and larger eyes than females. Compared to C. gasperettii, the relative head size of C. cerastes is larger and there is a greater frequency of horned individuals (13% versus 48%, respectively).<ref name="Mal03"/><ref name="Wer91">Werner YL, Verdier A, Rosenman D, Sivan N. 1991. Systematics and Zoogeography of Cerastes (Ophidia: Viperidae) in the Levant: 1. Distinguishing Arabian from African "Cerastes cerastes". The Snake 23: 90–100.</ref>

The colour pattern consists of a yellowish, pale grey, pinkish, reddish or pale brown ground colour, which almost always matches the substrate colour where the animal is found. Dorsally, a series of dark, semi-rectangular blotches runs the length of the body. These blotches may or may not be fused into crossbars. The belly is white. The tail, which may have a black tip, is usually thin.<ref name="Mal03"/><ref name="SB95">Spawls S, Branch B. (1995). The Dangerous Snakes of Africa. Dubai: Ralph Curtis Books. Oriental Press. Template:ISBN.</ref>

Common names

Common names of this species include desert sidewinding horned viper,<ref>Stevens, Austin (2005). SNAKEMASTER In Search of the Snake that Killed Cleopatra. [DVD] Michael Davies, USA: Discovery Communications, Inc.</ref> Saharan horned viper,<ref name="Mal03"/> horned s,<ref name="Meh87"/> Sahara horned viper,<ref name="SB95"/> desert horned viper, North African horned viper,<ref name="Bro73">Brown JH. (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, Illinois: Charles C. Thomas. LCCCN 73–229. Template:ISBN.</ref> African desert horned viper, greater cerastes,<ref name="USN91">U.S. Navy. (1991). Poisonous Snakes of the World. New York: Dover Publications Inc. (United States Government Reprint). Template:ISBN.</ref> asp and horned viper.<ref name="Dit33">Ditmars RL. (1933). Reptiles of the World. Revised Edition. New York: The MacMillan Company.</ref> In Egypt, it is called el-ṭorîsha (Template:Lang); in Libya, it is called um-Goron (Template:Lang).

Distribution and habitat

The snake is common in Iraq but is also found in Syria, Saudi Arabia, Palestine, Yemen, Jordan, Israel, Qatar, Mauritania, Morocco and Kuwait. They can also be found in parts of North Africa including Libya, Egypt, and Sudan.

Originally, the type locality was listed only as "Oriente." However, Flower (1933) proposed "Egypt" by way of clarification.<ref name="McD99"/>

These snakes favor dry, sandy areas with sparse rock outcroppings, and tend to avoid coarse sand. Occasionally they are found around oases, and up to an altitude of Template:Convert. Cooler temperatures, with annual averages of Template:Convert or less, are preferred.<ref name="Mal03"/>

Behavior

They typically move by sidewinding, during which they press their weight into the sand or soil, leaving whole-body impressions. Often, it is even possible to use these impressions to make ventral scale counts. They have a reasonably placid temperament, but if threatened, they may assume a C-shaped posture and rapidly rub their coils together. Because they have strongly keeled scales, this rubbing produces a rasping noise, similar to the sound produced by snakes of the genus Echis. In the wild, they are typically ambush predators, lying submerged in sand adjacent to rocks or under vegetation. The diet of this carnivorous species consists primarily of small rodents, geckos, birds, and a variety of lizards.<ref name="animaldiversity.org">Template:Cite web</ref> These vipers are also known to eat jerboas, yellow wagtails, and chiffchaffs.<ref name="animaldiversity.org"/> C. cerastes has been known to travel long distances at night in search of prey.<ref name="animaldiversity.org"/> When approached, they strike very rapidly, holding on to the captured prey until the venom takes effect.<ref name=FJ04>Photo sequence of Cerastes cerastes feeding in the wild (Gilf Kebir, Egypt, 27 October 2004) at FJ Expeditions accessed 19 October 2013</ref>

Reproduction

In captivity, mating was observed in April and always occurred while the animals were buried in the sand.<ref name="Mal03"/> This species is oviparous, laying 8–23 eggs that hatch after 50 to 80 days of incubation. The eggs are laid under rocks and in abandoned rodent burrows. The hatchlings measure 12–15 cm (about 5–6 inches) in total length.<ref name="SB95"/>

Venom

Cerastes cerastes venom is reported to be similar in action to Echis venom.<ref name="Mal03"/> Envenomation usually causes swelling, haemorrhage, necrosis, nausea, vomiting, and haematuria. A high phospholipase A2 content may cause cardiotoxicity and myotoxicity.<ref name="SB95"/> Studies of venom from both C. cerastes and C. vipera list a total of eight venom fractions, the most powerful of which has haemorrhagic activity. Venom yields vary, with ranges of 19–27 mg to 100 mg of dried venom being reported.<ref name="Mal03"/> For venom toxicity, Brown (1973) gives Template:LD50 values of 0.4 mg/kg IV and 3.0 mg/kg SC.<ref name="Bro73"/> An estimated lethal dose for humans is 40–50 mg.<ref name="SB95"/>

Taxonomy

A number of subspecies have been described:<ref name="Mal03"/>

Cerastes cerastes hoofieni Werner & Sivan, 1999 – Saudi Arabia.
Cerastes cerastes karlhartli Sochurek, 1974 – Egyptian horned viper – southeast Egypt and Sinai Peninsula.
Cerastes cerastes mutila Domergue, 1901 – Algerian horned viper – southwest Algeria, Morocco.