Dasypeltis scabra, known as the common egg eater, egg-eating snake or rhombic egg eater,[1] is a species of snake in the family Colubridae. It is endemic to Africa.
D. scabra grows to a total length (including tail) of 40–46 inches (100–120 cm), and has almost toothless jaws. Dorsally, it has a series of rhomboidal dark brown spots on a lighter background. There is an alternating series of brown spots on each side and a distinct V-shaped mark at the back of the neck. Ventrally it is yellowish, either uniform or with dark dots.[2]
Mimicry
It has been suggested that non-venomous Dasypeltis scabra is a mimic of venomous Echis carinatus, the saw-scaled viper, which it strongly resembles.[3]
Dasypeltis scabra, showing the keeled scales on the flank, the typical colouration, and the position of the V-shaped marking on the neck.
Typical specimens of D. scabra even more closely resemble Causus rhombeatus, the rhombic night adder. The colouration of Echis generally tends to be more reddish and brown, instead of shades of grey and black; and the V-shaped mark on its head is more patchy than in the other two species.
Causus is not as slim as Dasypeltis, and its scales, unusually among viperids, are at most slightly keeled, whereas Dasypeltis scales not only are keeled, but in some parts of the body are finely saw-toothed so that, when an alarmed snake rubs them against each other, they emit a threatening hissing sound. The species does not hiss in the usual manner at all. Both species typically have well-defined V-shaped markings on the head and neck, but in Causus the marking extends forward on the head, whereas in Dasypeltis it is mainly on the neck.
Furthermore, the two species also may be distinguished by the shape of the pupil of the eye. Snakes of the genusDasypeltis have vertically slitted pupils, whereas snakes of the genus Causus have round pupils.[4] However, in dim light the vertical pupils expand till they are rounded, so this is not necessarily a reliable criterion for distinguishing the species.
Habitat
Dasypeltis scabra can be found in a variety of habitats. They are not found in closed-canopy forests nor in true deserts, but do inhabit most ecosystems between these extremes.[5]
Behavior
The rhombic egg eater is nocturnal. Although mainly terrestrial, it is a good climber and is known to scale rock outcroppings and climb trees to raid birds' nests.[5]
Diet
Dasypeltis scabra feeds exclusively on eggs. The lining of the mouth has small, parallel ridges, very similar to human fingerprints, which aid in grasping the shell of an egg. Once swallowed, the egg is punctured by specialized vertebral hypapophyses which extend into the esophagus. The shell is then regurgitated in one piece, and its contents passed along to the stomach.[6]
Defense
When disturbed, D. scabra inflates itself, "hisses" by rapidly rubbing together the rough, keeled scales on the side of its body, and strikes with its mouth kept wide open.[7]
Reproduction
D. scabra is oviparous. In summer, a sexually mature female may lay one or two clutches of 6–25 eggs each. The eggs measure 36 mm × 18 mm (1.42 in × 0.71 in). Hatchlings are 21–24 cm (8.5–9.5 in) in total length.[5]
^Boulenger GA (1894). Catalogue of the Snakes in the British Museum (Natural History). Volume II., Containing the Conclusion of the Colubridæ Aglyphæ. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xi + 382 pp. + Plates I-XX. (Dasypeltis scabra, pp. 354–357).
^Sternfeld R (1910). "Zur Schlangenfauna Deutsch-Südwestafrikas. Mehrere Fälle von Mimikry bei afrikanischen Schlangen". Mit. zool. Mus. Berlin5: 51–60. (in German).
^Causus rhombeatus at Life Desks, Snake Species of the World. http://snakeArchived 2013-07-27 at the Wayback Machine species of the world.lifedesks.org/pages/360.
^ abcBranch, Bill (2004). Field Guide to Snakes and other Reptiles of Southern Africa. Third Revised edition, Second impression. Sanibel Island, Florida: Ralph Curtis Books. 399 pp. ISBN0-88359-042-5. (Dasypeltis scabra, pp. 95-96 + Plate 15).
^Mattison, Chris (2006). Snake. New York: DK Publishing. 192 pp.
^Gans, Carl; Richmond, Neil D. (1957). "Warning Behavior in Snakes of the Genus Dasypeltis". Copeia1957 (4): 269-274.
^"Dasypeltis scabra ". The Reptile Database. www.reptile-database.org.
Further reading
Linnaeus C (1758). Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Decima, Reformata. Stockholm: L. Salvius. 824 pp. (Coluber scaber, new species, p. 223). (in Latin).
Mertens R (1954). "Neue Schlangenrassen aus Südwest- und Südafrika". Zoologischer Anzeiger152: 213-219. (Dasypeltis scabra loveridgei, new subspecies). (in German).
Morris PA (1948). Boy's Book of Snakes: How to Recognize and Understand Them. A volume of the Humanizing Science Series, edited by Jaques Cattell. New York: Ronald Press. viii + 185 pp. (Dasypeltis scaber, pp. 143, 181).
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