piątek, 1 lipca 2011
Reptiles - Savannah Monitor
The savanna monitor (Varanus exanthematicus) is a species of monitor lizard native to Africa. The species is known as Bosc's monitor in Europe, since French scientist Louis Bosc first described the species. It belongs to the subgenus Polydaedalus, along with the Nile, the ornate and other monitors.
The generic name Varanus is derived from the Arabic waral (ورل), which translates as "monitor" in English. The specific name exanthematicus is derived from two Greek words: exanthema meaning "eruption" and mata meaning "idle". French botanist and Zoologist Louis Augustin Guillaume Bosc originally described this lizard as Lacerta exanthematicus in reference to the large oval scales on the back of the neck.
The savanna monitor has powerful limbs for digging and climbing, very powerful jaws that can easily crush bone, and very strong, sharp teeth. Maximum size is usually 2.5 feet and rarely more than 5 feet in length. Most are usually around 3.0 to 3.5 feet. The pattern on the back of Varanus exanthematicus is uniformely grey to pale yellow. The monitor has a short, box-like head and large dorsal and nuchal scales. Its short tail is round, and stores fat as an energy reserve.
The savanna monitor typically defends itself with its strong bite and powerful jaws. Its thick hide makes it resistant to most animal bites, and herpetologist Robert Sprackland claims the lizard is immune to most snake venom. When confronted by a snake or other large predator, the monitor rolls onto its back and grasps a hind leg in its mouth, forming a ring with its body and making itself harder for the animal to swallow whole. Savanna monitors, like most monitors, will expand their throat and body. They also will gape and let out a slow, deep hissing sound when threatened.
The savannah monitors are carnivores or insectivores, generally a low-fat diet. Although the savannah monitor is willing to eat mammals, it is not recommended for them be fed mammals, such as mice, in captivity. Mammals are high in fat and cause the liver to enlarge, and can even lead to fatty liver disease. Monitors will eat insects, small mammals, eggs, birds, smaller monitors, snakes and dead animal remains. The feeding response of a savannah monitor is very aggressive. Monitors should not be hand-fed or fed near other monitors. They find and track prey by using their Jacobson's organ, which is located in the roof of their mouths. The Jacobson's organ is a secondary olfactory sense organ for many animals, including reptiles.