środa, 20 lipca 2011

Tortoise - Common snapping turtle

The common snapping turtle (Chelydra serpentina) is a large freshwater turtle of the family Chelydridae. Its natural range extends from southeastern Canada, southwest to the Rocky Mountains as far east as Nova Scotia and Florida. This species and the larger alligator snapping turtle are both widely referred to as snapping turtles or snappers (though the common snapping turtle, as its name implies, is much more widespread overall).

Common snappers are noted for their belligerent disposition when out of the water, their powerful beak-like jaws, and their highly mobile head and neck (hence the specific name "serpentina", meaning "snake-like"). In some areas they are hunted very heavily for their meat, a popular ingredient in turtle soup. These turtles have lived for up to 47 years in captivity, while the lifespan of wild individuals is estimated to be around 30 years

Chelydra serpentina have rugged, muscular builds with ridged carapaces (though ridges tend to be more pronounced in younger individuals). The carapace (upper shell) length in adulthood may be nearly 50 cm (20 in), though 25–7 cm (9.8–2.8 in), is more common, with C. serpentina and its subspecies commonly weighing 4.5–16 kg (9.9–35 lb). Exceptionally large (often captive and overfed) individuals may reach 34 kg (75 lb).

The common snapping turtle is not an ideal pet. Its neck is very flexible, and the turtle can bite its handler even if picked up by the sides of its shell. The turtle can amputate a finger with its powerful jaws. It will make a hissing sound when it is threatened or encountered; however, when in the water and unprovoked, they are fairly docile toward humans.

It is a common misconception that common snapping turtles may be safely picked up by the tail with no harm to the animal; in fact, this has a high chance of injuring the turtle, especially the tail itself and the vertebral column. Lifting the turtle with the hands is difficult and dangerous. Snappers can stretch their necks back across their own carapace and to their hind feet on either side to bite. Also, their claws are sharp and capable of inflicting significant lacerations.

It may be tempting to rescue a snapping turtle found in a road by getting it to bite a stick and then dragging it out of immediate danger. This action can, however, severely scrape the legs and underside of the turtle and allow for deadly infections in the wounds.

środa, 6 lipca 2011

Tortoise - Russian tortoise/Horsfield's tortoise/Central Asian tortoise

The Russian tortoise, Horsfield's tortoise or Central Asian tortoise (Testudo horsfieldii, but see "Systematics" below) is a species of tortoise that is a popular pet. It is named after the American naturalist Thomas Horsfield.

The Russian tortoise is a small tortoise species, ranging from about 15 to 25 cm (6-8 inches for males, 8-10 inches for females). They are sexually dimorphic in that the females grow slightly larger, males tend to have a longer tail that is generally tucked to the side, and females tend to have flared scutes on their shells, while males do not. Coloration varies, but the shell is usually a ruddy brown or black, fading to yellow between the scutes, and the body itself straw-yellow and brown. They have four toes. They live for so long (about 75 years) that people who keep them as pets often leave them in their will. They are usually rather social with humans. They are a popular pet.

The Russian tortoise ranges from Afghanistan to north-western China, through the countries of Russia,m Armenia, Azerbaijan, Turkey, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, Iran, and Pakistan. It usually lives in dry areas with sparse vegetation.

Russian tortoises hibernate during winter and estivate during the summer when temperatures are high. They are avid burrowers and can dig large burrows that might be two meters (six feet) long. They are herbivorous, and active grazers when the temperature is right, consuming a wide variety of weeds and grasses. In captivity, suitable foodplants include:

- Lactuca sativa lettuce, especially Romaine and green and red Looseleaf cultivars
- Dandelions, a favorite

In the wild, the Russian Tortoise is considered vulnerable to extinction in the mid-long term. Human construction encroaching upon its habitat is the main cause of endangerment; it is also hunted locally for use in folk medicine. Trade in wild animals is restricted, and captive-breds should be preferred as pets as they are hardier. They also tend to be less shy than other tortoises and have an appealing, pugnacious temperament.

In captivity
Russian tortoises are popular pets primarily because of their small size, and they are also an extremely hardy species. While captive breeding is becoming more commonplace, large retailers rely on wild caught specimens to sell as pets. These are sometimes in poor health because of the stress of capture and transport. Russian tortoises kept as pets readily consume a wide variety of greens and weeds. While they will also eat fruit, it should not be given, as excess sugars can cause bacterial blooms in their stomachs. They need exposure to UVB lighting to metabolize food.

First tortoise in space
The first tortoise in space, and one of the first animals of any kind in deep space was a Russian Tortoise, sent by the Soviet Union (along with wine flies, mealworms and other biological specimens) on a circumlunar voyage from September 14 to September 21, 1968.

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".[citation needed] 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.