These are legless reptiles with a left lung that is either reduced or absent.
Hearing: they lack external ears. F1 they pick up ground and air-borne vibrations
A ligament joins the two halves of the lower jaw and each can move independently.
The ribs are loosely attached to the vertebrae allowing for the abnormal swelling of the body cavity when swallowing large prey.
Smell: the tongue is pushed out from a sheath in the mouth through a small gap in the lips to pick up air borne particles. It is returned and the fork inserted into the organ of Jacobson in the roof of the mouth…a specialised smelling (olfactory) organ where the information is interpreted.
Eyesight: They do not have eyelids. Their eyesight varies from blind in some of the fossorial species to the keen eyesight of arboreal species…inter alia the boomslang and vine snakes. Movement is an important factor for non-fossorial species to pick up prey/predators.
F1 Speed: the black mamba, one of the faster southern African snakes, barely reaches 20kph and, because the oxygenating the blood is slow, they are unable to maintain top speed for any length of time.
Snouted cobras (L3 family: elapidae) (i. Naja annulifera) can exceed 2m when fully grown. The colour varies through all shades of brown on the back whilst the under parts are cream coloured with dark blotching and a black band across the throat. Nocturnal.
Defence: similar to the Cape cobra, it lifts the front of the body erect and spreads its hood. It has fixed front fangs
Note: Anchieta’s cobra (closely related to the snouted cobra) is similar in most visual respects to the snouted cobra however the distribution of A.c is the far north and north-western areas of southern Africa.)
Food: the diet includes rodents, frogs, reptiles and young birds.
Habitat: Prefers the eastern and north-eastern parts of southern Africa where it is wetter and warmer than the south and western areas Reproduction: Oviparous
Mozambique spitting cobra (L3 family: elapidae) (i. Naja mossambica) reaches1.5m and colour varies from a grey to dark brown. It has a cream underbelly with blotchy black band/s across the throat. Nocturnal/diurnal but more active at night.
Food: the diet includes rodents, frogs, reptiles and young birds and puff adders.
Habitat: Often found near water and prefers the warmer climates of southern Africa
Venom: cytotoxic…with some neurotoxic mix.
Boomslang (L3 family: colubridae) (i. Dispholidus typus) can grow to 2m long. These snakes are dimorphic and regionally highly variable. In Botswana the female is a mid-brown with a slightly paler underbelly. The male is medium to dull green. The juvenile is striking with orange on the throat and a bluish upper neck. The eyes of this snake are noticeably larger than other snakes and the rough keeled scales make this an easy snake to identify. They are one of very few snakes in the world able to see stationary prey/predators. Diurnal.
Food: they eat birds and their eggs, chameleons, frogs and lizards
Habitat: arboreal and occur through most of southern Africa except very arid areas.
Reproduction: Oviparous and lay 8 to 25 eggs
Venom: haemotoxic…attacks red blood cells and prevents blood clotting.
There are four methods of forward movement:
Serpentine (F1 lateral undulation): is the most frequent type of locomotion used, especially by the slender, agile snakes. The snake glides forward in a series of waves. Forward movement is dependent upon the presence of irregularities on the surface over which the snake is moving. When the snake is moving in an “S” shape, the sides of the curves come into contact with objects in its path, thus propelling the body forward. Most snakes use this type of locomotion.
Rectilinear (F1 caterpillar–like): is used by heavy bodied species…puff adders and mature pythons. The snake moves forward in a straight line with no lateral movement. The ventral (bottom) scales have very little resistance moving forward along the surface but when pulled backwards the scale edges give a grip that propels the snake forward. This is done in such a way that there are always ventral scales moving forward and others moving backwards thus ensuring a continuous forward motion.
Concertina: is a specialised locomotion restricted to burrowing forms of snakes such as the burrowing asp. The rear end of the body is forced against the walls of the tunnel and the front end is thrust forward. The front end then presses against the side of the tunnel to provide the resistance to contract the back end of the body forward. ..To continue reading .. download the full manual