Savannah monitor | |
---|---|
Adult in captivity | |
Juvenile | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Family: | Varanidae |
Genus: | Varanus |
Subgenus: | Polydaedalus |
Species: | V. exanthematicus |
Binomial name | |
Varanus exanthematicus (Bosc, 1792) | |
The savannah monitor (Varanus exanthematicus) is a medium-sized 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. [2] It belongs to the subgenus Polydaedalus .
The specific name exanthematicus is derived from the Greek word exanthem /ɛkˈsænθɪm/ , meaning an eruption or blister of the skin. [3] French botanist and zoologist Louis Augustin Guillaume Bosc [4] originally described this lizard as Lacerta exanthematica in reference to the large oval scales on the back of its neck. [2]
The species was formerly known as Lacerta exanthematicus. [5]
Savannah monitors are stoutly built, with relatively short limbs and toes, and skulls and dentition adapted to feed on hard-shelled prey. They are robust creatures, with powerful limbs for digging, powerful jaws and blunt, peglike teeth. Maximum size is rarely more than 100 cm. The skin coloration pattern varies according to the local habitat substrate. The body scales are large, usually less than 100 scales around midbody, a partly laterally compressed tail with a double dorsal ridge and nostrils equidistant from the eyes and the tip of the snout. [6]
The savannah monitor is often confused with the white-throat monitor (Varanus albigularis), which can grow to lengths of 5–6 ft. While similar in overall appearance, this species possesses significant morphological and ecological differences and is recognized as a very distinct species.
Their diet is much more restricted than that of other African monitor lizards, consisting mainly of snails, crabs, scorpions, millipedes, centipedes, orthopterans, mantids, hymenopterans, lepidopterans, beetles and other invertebrates, as well as frogs. [7] [8] Information about the diet of savannah monitors in the wild has been recorded in Senegal and Ghana. [9] [10] [11] It feeds almost exclusively on arthropods and molluscs. In Senegal, Julus millipedes were the most common prey of adults; in Ghana, small crickets formed the bulk of the diet of animals less than 2 months old; orthopterans (especially Brachytrupes ), scorpions and amphibians were the most common prey of animals 6–7 months old. Many adults also consume large quantities of snails. Full grown V. exanthematicus have teeth that are quite blunt to help them crack and eat snails. The jaw has evolved to put maximum leverage at the back of the jaw to crush snail shells. Adults will also eat carrion if they come across it. [12] Wild savannah monitors are also known to occasionally eat lizard eggs (such as those of agamids and their own kind). [13] [14]
Females dig a deep hole in the substrate, in which up to 40 or more eggs are laid, which hatch after about 156–160 days. Hatchlings start feeding a few days after the yolk sac has been absorbed, which may take 12 days or more after hatching. [15]
The savannah monitor is the most common monitor lizard species available in the pet trade, accounting for almost half (48.0552%) of the entire international trade in live monitor lizards. [16] Despite its prevalence in global pet trade, successful captive reproduction is very rare, and a high mortality rate is associated with the species. [17] Adult specimens frequently become unwanted pets and are reported as being the most common monitor lizards by animal rescue agencies. The skins are traded within the international leather trade and originate mainly from Chad, Mali and Sudan.[ citation needed ]
Its range extends throughout sub-Saharan Africa from Senegal east to Sudan and south almost to the Congo River and Rift Valley, where they are replaced by V. albigularis . [10] V. exanthematicus is primarily a ground-dwelling species that shelters in burrows, although it is sometimes found in bushes or low trees. [6] In the coastal plain of Ghana, V. exanthematicus juveniles are often associated with the burrows of the giant cricket Brachytrupes . [18]
V. exanthematicus is listed as least concern by IUCN. [1] The species is hunted for its leather and meat, and for the international pet trade. The trade in wild collected savannah monitors is not of a global conservation concern, due to the vast range of the species; in addition to the collection for the pet trade often occurring over a relatively small area. [19] An average of 30,574 live specimens were imported into the US each year, between 2000 and 2009; total imports of live specimens into the US between 2000 and 2010 was 325,480 animals. During the same period, 1,037 skins, shoes, and products of the species were imported into the US. Trade in live animals comes mainly from Ghana (235,903 animals exported between 2000 and 2010), Togo (188,110 animals exported between 2000 and 2010), and Benin (72,964 animals exported between 2000 and 2010). During the same period, total worldwide declared exports of skins and products of the species totalled 37,506. [20] However, substantial undeclared trade in the species occurs from Sudan, Nigeria, and elsewhere. [1] Within several West African nations, roadside diners and food stands specialize in “monitor stew”, a hot simmered dish of local vegetables and savannah monitor; it is unclear whether the cooked lizards are hunted or bred specifically for human consumption, or at what rate they are being killed for this purpose. [21]
Monitor lizards are lizards in the genus Varanus, the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recognized.
The Nile monitor is a large member of the monitor family (Varanidae) found throughout most of Sub-Saharan Africa and along the Nile, with invasive populations in North America. The population in West African forests and savannahs is sometimes recognized as a separate species, the West African Nile monitor. It is one of the largest lizards in the world reaching and even surpassing the perentie by size. Other common names include the African small-grain lizard, as well as iguana and various forms derived from it, such as guana, water leguaan or river leguaan. A feral population of the lizards, descended from escaped or intentionally released pets, has become established in several locations in Florida.
The Bengal monitor, also called the common Indian monitor, is a monitor lizard distributed widely in the Indian Subcontinent, as well as parts of Southeast Asia and West Asia. This large lizard is mainly a terrestrial animal, and its length ranges from about 61 to 175 cm from the tip of the snout to the end of the tail. Young monitors may be more arboreal, but adults mainly hunt on the ground, preying mainly on arthropods, but also taking small terrestrial vertebrates, ground birds, eggs and fish. Although large Bengal monitors have few predators apart from humans who hunt them for meat, younger individuals are hunted by many predators.
The desert monitor is a species of monitor lizard of the order Squamata found living throughout North Africa and Central and South Asia. The desert monitor is carnivorous, feeding on a wide range of vertebrates and invertebrates.
The Asian water monitor is a large varanid lizard native to South and Southeast Asia. It is one of the most common monitor lizards in Asia, ranging from coastal northeast India, Bangladesh, Sri Lanka, mainland Southeast Asia, and southern China to Indonesian islands where it lives close to water. It is listed as Least Concern on the IUCN Red List. It was described by Laurenti in 1768 and is among the largest squamates in the world.
The black tree monitor or Beccari's monitor is a species of lizard in the family Varanidae. The species is a relatively small member of the family, growing to about 90–120 cm (35–47 in) in total length. V. beccarii is endemic to the Aru Islands off New Guinea, living in an arboreal habitat. The skin color of adults is completely black, to which one common name refers.
The mangrove monitor, mangrove goanna, or Western Pacific monitor lizard is a member of the monitor lizard family with a large distribution from northern Australia and New Guinea to the Moluccas and Solomon Islands. It grows to lengths of 3.5 to 4 ft.
The emerald tree monitor or green tree monitor, is a small to medium-sized arboreal monitor lizard. It is known for its unusual coloration, which consists of shades from green to turquoise, topped with dark, transversedorsal banding. This coloration helps camouflage it in its arboreal habitat. Its color also makes the emerald tree monitor highly prized in both the pet trade and zoos alike.
The spiny-tailed monitor, also known as the Australian spiny-tailed monitor, the ridge-tailed monitor the Ackie's dwarf monitor, and colloquially simply ackie monitor, is an Australian species of lizard belonging to the genus of monitor lizards (Varanus).
The Gray's monitor is a large monitor lizard known only from lowland dipterocarp forest in southern Luzon, Catanduanes, and Polillo Island, all islands in the Philippines. It is also known as Gray's monitor lizard, butaan, and ornate monitor. It belongs to the subgenus Philippinosaurus. It is largely arboreal and extremely shy. The Northern Sierra Madre monitor lizard was thought to be of same species with Gray's monitor until a research concluded in 2010 that northern populations of Gray's monitor was a distinct species, now known as V. bitatawa.
The white-throated monitor is a lizard found in southern Africa. They are usually gray-brown with yellowish or white markings, and can reach up to 2 metres (6.6 ft) in length. They are found in Southern Africa, northwards to Angola, Zambia, and Mozambique.
The rock monitor is a species of monitor lizard in the family Varanidae. The species is endemic to Central, East, and southern Africa. It is the second-longest lizard found on the continent, and the heaviest-bodied; locally, it is called leguaan or likkewaan.
The black-throated monitor is a subspecies of monitor lizard in the family Varanidae. The subspecies is native to Tanzania.
The Rosenberg's monitor is an Australian species of varanid reptile found in southern regions of the continent. They are large and fast predators with rugged bodies and long tails, having a combined length up to 1.5 metres, that will consume any smaller animal that is pursued and captured or found while foraging. They occur in the Australian Capital Territory, New South Wales, South Australia, Victoria, where it may be rare or locally common, and more frequently observed in Western Australia, where it is sometimes abundant.
The turquoise monitor is a species of monitor lizards found in Indonesia. Specifically, it is found on Halmahera Island and in the Maluku Islands.
Dumeril's monitor is a species of lizard in the family Varanidae. The species is endemic to Southeast Asia.
Mitchell's water monitor is a semiaquatic species of monitor lizard in the family Varanidae. The species is native to Australia. The species is native to the Northern regions of Australia, and is on IUCN's Red List as a critically endangered species. They can be distinguished by the orange or yellow stripes along their neck and dark spots along their back. They are mainly carnivorous, and eat small prey such as lizard, birds, and insects.
Storr's monitor is a species of monitor lizard in the family Varanidae. The species is endemic to Australia.
The subgenus Odatria, sometimes known as the dwarf monitor lizards, consists of small monitor lizards found in Australia and Indonesia. Species in this subgenus include the smallest monitor species in the world, the tiny 16 gram Dampier Peninsula monitor, but also includes some more medium sized species such as the 240 gram black-palmed rock monitor.
{{cite book}}
: |author=
has generic name (help)