AW Reptile Book: Snake Families

Sat Feb 16, 2013 2:46 pm

Family Elapidae - Fixed Front Fang Snakes
Predominantly the Mambas & Cobras. The Elapidae consists of about 300 species in 61 genera, and includes some of the most dangerous snakes in the world. Most of these snakes are very fast and agile. The Black mamba (Dendroaspis polylepis) for example, is the fastest snake in the world.
This group is highly venomous, with fixed front fangs.

Image

They do not have a loreal scale and most have round pupils. Other than the Rinkhals that has keeled scales the rest are shiny & smooth scaled.
There are a few exceptions but the bulk of the group are oviparous. The larger species have elaborate defensive displays and seem aware of their dangerous abilities and will often stand their ground to a threat.
Most of the group are fairly large snakes and terrestrial. Elapids have adapted to many different habitats, including borrowing and a marine environment (seasnakes).

Image
Image

Re: AW Reptile Book: Snake Families

Sat Feb 16, 2013 4:14 pm

Family Colubridae - Typical Snakes

A very diverse group that includes almost 2000 species, distributed throuout tropical and temperate regions. This family is well represented in Southern Africa, with more than 85 species. Most colubrids are nonvenomous (or have venom that is not known to be harmful to humans) and are harmless.

Most species are medium sized. They don't have a functional left lung or pelvic vestiges. Most species lack fangy, but some have back fangs. The head usually has large, symmetrical scales. Most have wide scales on their bellies and, usually, nine large scales on the tops of their heads. Most colubrids also have glands, or groups of cells, behind each eye. These glands squeeze out a mixture of chemicals that, in some species, oozes through enlarged back teeth, known as rear fangs. Unlike the cobras and vipers, whose fast-acting venom can knock out or kill an animal in moments, the colubrids produce venom that is not as strong and usually takes many minutes to work. The boomslangs and a few other species are exceptions to the rule; they have venom powerful enough to kill humans.

Image

Image
Image
Image
Image
Image

Re: AW Reptile Book: Snake Families

Thu Feb 21, 2013 9:27 am

Family Viperidae - Vipers

All viperids have a pair of relatively loang erectile hollow fangs at the front of the mouth. When not in use, the fangs fold back and are enclosed in a membranous sheath. The head is distinct and usually covered with small, irregular, overlapping scales. But night adders have large head shields like those of the colubrids. The great majority have vertically elliptical, or slit-shaped, pupils that can open wide to cover most of the eye or close almost completely, which helps them to see in a wide range of light levels.
Almost all vipers have keeled scales (but smooth in night adders), a stocky build with a short tail, and, due to the location of the venom glands, a triangular-shaped head distinct from the neck.
These short to large snakes are mainly terrestrial (some arboreal, one species is a burrowing snake, several are semi-aquatic). Typically, vipers are nocturnal and ambush their prey that is killed by their venom. They feed on small vertebrates.
Most are ovoviviparous, giving birth to live young, but a few lay eggs.

Head scales:

Image Typical vipers have fragmented and keeled scales.

Image Night adders have smooth colubrid-like scales.


Key to Southern African genera in the viperidae:

Image

Re: AW Reptile Book: Snake Families

Tue Feb 26, 2013 7:12 pm

Family Typholidae - Blind Snakes

The Typhlopidae are a family of blind snakes. They are found mostly in the tropical regions of Africa. The rostral scale overhangs the mouth to form a shovel like burrowing structure. They live underground in burrows, and since they have no use for vision, their eyes are mostly vestigial. They have light-detecting black eyespots, and teeth occur only in the upper jaw. The tail ends with a horn like scale. Most of these species are oviparous.
Blind snakes are nonvenomous and totally harmless. They feed on ants and termites, especially the larvae and pupae, and the distribution of each species is related to the distribution of its primary prey species. They have an efficient way of eating where the toothed maxillae move in and out of the mouth in a raking motion which allows the consumption of large numbers of prey in a short period.
Blind snakes are part of the food chain and their main defense is to burrow and stay out of the way of predators. They are able to emit an unpleasant odor from anal glands. When grabbed, they thrash wildly, defecate and stab the offender with their tail spine. Most of their lives are spent underground but sometimes they move around the surface at night, especially after summer rains.

This family is represented by three genera in southern Africa.
Rhinotyphlops
Represented by four species in southern Africa.
Rhinotyphlops boylei (Boyle's beaked blind snake)
Rhinotyphlops lalandei (Delalande's beaked blind snake)
Rhinotyphlops schinzi (Schinz's beaked blind snake)
Rhinotyphlops schlegelii (Schlegel's beaked blind snake)

Typhlops
This genus is represented by three species in southern Africa.
Typhlops obtusus (Slender blind snake)
Typhlops fornasinii (Fornasini's blind snake)
Typhlops bibronii (Bibron's blind snake)

Ramphotyphlops (naturalised in southern Africa)
One species: Ramphotyphlops braminus (Flowerpot snake)