Uromastyx

From Wikipedia, the free encyclopedia

Uromastyx

Submitted as Uromastyx dispar, though most likely a male U. maliensis

Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Family:	Agamidae
Subfamily:	Leiolepidinae
Genus:	Uromastyx

The Uromastyx is a genus of lizard whose members are better-known as Spiny-tailed lizards, uros, or dabb lizards. Uromastykes are primarily herbivorous, but occasionally eat insects, especially when young. They spend most of their waking hours basking in the sun, hiding in underground chambers at daytime or when danger appears. They tend to establish themselves in hilly, rocky areas with good shelter and accessible vegetation.

Uromastyx hardwickii

Their size ranges from 14 inches (U. hardwickii) to 36 inches or more (U. aegyptius). Hatchlings or neonates are usually no more than 3-4 inches in length. Like many reptiles, these lizards' colors change according to the temperature; during cool weather they appear dull and dark but the colors become lighter in warm weather, especially when basking; the darker pigmentation allows their skin to soak up more sunlight. They inhabit a range stretching through most of North Africa, the Middle East and across south-central Asia and into India. This area spreads across 5000 miles and 30 countries. They occur at elevations from sea level to well over 3000 feet. They are regularly eaten, and sold in produce markets, by local peoples. Uromastyx tend to bask in areas with surface temperatures of over 120 °F. The spiked tail is muscular and heavy, and can be swung at an attacker with great velocity, usually accompanied by hissing and an open-mouthed display of (small) teeth. Uros generally sleep in their burrows with their tails closest to the opening, in order to thwart intruders.

A female uromastyx can lay anywhere from 5 to 40 eggs, depending on age and species. Eggs ideally hatch 2 to 3 months after laid. Female uros are smaller and less colorful than males. For example, U. maliensis females are light tan with black dorsal spots, while males are mostly bright yellow with mottled black markings. Females also tend to have shorter claws.

Female Mali uromastyx.

Members of the genus can be found for sale in pet stores in the United States. However, it is usually preferable to purchase one from a breeder where the facility can be inspected and tips obtained on care and handling. This will also ensure the purchase of a captive-bred lizard and not a wild-caught lizard, which may have foreign diseases.

Initially, uromastyxes in captivity had a poor survival rate, due to a lack of understanding of their dietary and environmental needs. In recent years, knowledge has significantly increased, and appropriate diet and care has led to survival rates and longevity approaching those in the wild. They generally become very tame and will eat out of their owners' hands.

The Mali uromastyx is considered an ideal species to choose as a pet because they readily adapt to the captive environment. Another good species of Uromastyx that adapts to captivity, and comes in some beautiful color varieties, is Uromastyx ocellata ornata. Artificial UVB/UVA light and vitamin supplements must be balanced with proper food and nutrition. Proper enclosures can be costly, as these are roaming animals with large space needs for their size, combined with the need to provide heat and ultraviolet light. Though the lizards bask at very high temperatures, there must be a temperature gradient within the enclosure allowing them to cool off away from the heat lamps. A cooling-down period over winter months can trigger the breeding response when temperatures rise in the spring. The temporary slowing-down of their metabolisms also lengthens the animals' lifespans.

Egyptian spiny-tailed lizard (Uromastyx aegyptius) in an English zoo

Uromastyxes are burrowing lizards, and need substrate deep enough to burrow in, or a low structure under which to hide. In the wild, these lizards' burrows can reach 10 feet in length. The best substrate is sand, particularly the rounded-particle variety known as "play sand." A popular alternative (except for babies under a year) is compressed coconut fiber bricks; this must be rehydrated with hot water and then used in a completely dry state. Drying out the substrate, once it has been watered to expansion and breaking apart the large chunks, can take a few days. Another inexpensive substrate that can pass through the digestive system without problems is millet seed. This can be easily sifted with a wire mesh to clean waste from the enclosure. Healthy, well-nourished adults do very well on sand, since they have adapted to it over millennia in the wild. The average cost for getting all of the materials for the uromastyx is 200 dollars.

[edit] Nutrition

These lizards acquire most of the water they need from the vegetation they ingest. They have rarely been observed drinking standing water. (They may urinate when frightened; this can rapidly deplete their crucial water stores.) The humidity of the enclosure must be kept low to prevent respiratory problems. Captive uros’ diets must be predominantly herbivorous, consisting of endive, dandelion greens, Bok Choy, and escarole. Lettuce has almost no nutritive value, but can be given once in a while as a water source. They can consume de-thorned cacti with their powerful jaws, especially if they need water. The lizards' food should be frequently dusted with a calcium and a uromastyx designed supplement to help prevent health problems. It is very important to avoid spinach, chard, flowering kale, and parsley in the diets of all reptiles, since the oxalates in spinach prevent the uptake of calcium into the bloodstream. Some believe feeding insect foods, such as crickets and mealworms, should be avoided because of health problems, but many other breeders and hobbyists maintain that insects can be a small part of the animal's diet (less than 10% of all foods eaten) without any danger to the lizard. A good diet plan is plant matter every day or every other day, and insects every month or two. Insect protein is difficult for uros' livers to digest.