Dasypeltis

Ordinary egg-eating snake ( Dasypeltis scabra )

The African egg-eaters ( Dasypeltis ) are a genus of snakes of the family ( Colubridae ) in the subfamily of the land and tree snakes ( Colubrinae ).

Description

Dasypeltis species are slender, rather delicate snakes with a small, blunt head, which is only slightly separated from the body. They reach a length of 50 to 110 cm, the females are slightly larger than males. Her pupils have a vertical elliptical shape. Common to all types is the absence of Loreal Scale on the head. Therefore, the half- split Nasalschuppe with the nasal opening is adjacent to the Präokulare. The median chin shield is not shared by a Mental pit. The 23 to 27 rows of body scales are strongly keeled. In three to four rows of scales on the sides of the body, these keels are also finely serrated. The coloring of the individual species, especially the ordinary egg-eating snake, is highly variable, making a correct determination difficult. The colors range from light brown to gray to dark olive. Often black spots are present in varying density. Eggs snakes are non-toxic. They have each half of the jaw only 3-7 small teeth that are hidden in the gums and for example the human skin can not penetrate.

Distribution and habitats

The representatives of the genus are native to sub-Saharan Africa. Relict occurrence of the widespread nature Dasypeltis scabra but there are also still in the Atlas Mountains ( SW Morocco ) and in the south west of the Arabian Peninsula.

The preferred habitats ranging from savannah to open woods and cultivated land. Deserts and closed, tropical forests are avoided.

Behavior and lifestyles

Daily rhythm

African egg-eaters are crepuscular and nocturnal. During the day they hide in termite mounds like. They are good climbers and swimmers.

Nutrition

Together with the Indian egg-eating snake ( Elachistodon westermanni ), the African egg-eaters are the only purely oviphagen ( egg -eating ) snakes in the world. Occasional Oviphagie other hand, occurs in several snakes. Depending on the part of the complex species and populations may specialize in different bird species. In the savannahs eggs snakes climb trees regularly in order to get to the nests of weaver birds of the genus Ploceus. Did the snake found a nest with fresh eggs, they first checked by scanning with the head base, whether they can cope with the egg in size. Then she pushes her extremely movable jaw on the egg, stating saliva on its surface. The very elastic skin in the front body section is extensible to three or four times, so that adult snakes eggs, which are about thumb thick, can swallow eggs up to the size of a chicken egg. Is opened the egg, by being pressed in along downward extensions projecting into the esophagus of the vertebrae 17-38. The front of the enamel coated with extensions ( hypapophyses ) slots on the egg. Contraction of the muscles in this body section, the egg is then crushed to the widened middle hypapophyses and swallowed the liquid contents. The empty egg shell is thereby compressed into a sausage-shaped Speiballen. Front-facing spinous in another section prevent the egg shell slips in the stomach. Instead, it is transported through antiperistaltic movements back to the head and regurgitated. Lazy or even longer incubated eggs will not be eaten. In the north and south of their range must Dasypeltis species, due to the limited breeding season of birds, six to eight months to about survive periods of fasting. They live off during this period by the body fat that they have invested in the breeding season of birds.

Enemy behavior

Potential predators are mainly ophiophage ( snake -eating ) snakes like Liane vipers, cobras and boom Lang, but also baboons and wild pigs. Because of their weak dentition and lack venom glands Dasypeltis the species are defenseless. They imitate with their appearance and behavior, however, poisonous snakes and are relatively well protected under this mimicry. The fact that occur very different poisonous snakes in their large distribution area, is the view of evolution researchers also the reason for the large color variability of the egg-eaters. To mimic occurring in different regions of Africa populations depending on the sympatric models Echis species (eg Echis pyramidum ), puff adders ( Bitis caudalis example ), bush vipers, marsh vipers ( Proatheris superciliaris ) or toads vipers as Causus rhombeatus. In addition, the animals can straighten, blow up their front body slightly and push for the enemy. Another form of defensive behavior is that they put their bodies into parallel U- shaped loops and constantly moving, so that the corrugated shed keels rub against the sides of the body together and make a characteristic sound, similar to that of toxic sand race wobble.

Systematics and history of research

The genus Dasypeltis 1830 was drawn up by Johann Georg Wagler, after the animals had previously been mostly classified in the genus Coluber. In 1834, observed and described by French naturalist Claude Jourdan first time the diet and pointed to the anatomical peculiarities. A detailed study of this behavior and the underlying adjustments was presented in 1952 by the German engineer and zoologist Carl Gans. The same author published in 1959 a revision of the genus.

According Reptile Database eleven types can be distinguished:

• Dasypeltis abyssina
• Dasypeltis atra
• Dasypeltis confusa
• Dasypeltis fasciata
• Dasypeltis Gansi
• Dasypeltis inornata
• Dasypeltis latericia
• Dasypeltis medici
• Dasypeltis parascabra
• Dasypeltis sahelensis
• Dasypeltis scabra

Swell

• George A. Boulenger: Catalogue of the Snakes in the British Museum (Natural History ), Volume 2, Reprint 1961.
• William R. Branch: Field Guide to Snakes and other Reptiles of Southern Africa, 2nd edition, 1998.
• Maurice Burton & Robert Burton: International Wildlife Encyclopedia, 3rd edition, 2002.
• Harry U. Greene, Patricia Fogden, Michael Fogden: Snakes: The Evolution of Mystery in Nature, 2000.
• Hans -Hermann Schleich, Werner Kastle, Klaus Kabisch: Amphibians and Reptiles of North Africa. Biology, Systematics, Field Guide, 1996.
• Dasypeltis in The Reptile Database
• Map of the distribution areas of D. scabra, D. salehensis, D. confusa, D. and D. atra abyssina