Reptiliana: Ultimate Reptile Resource

Dumeril’s Monitor – Varanus dumerilii
March 1, 2008, 11:52 pm
Filed under: Monitors, Reptiles | Tags: ,

Dumeril’s Monitor is a large, elusive lizard native to Southeastern Asia. Until several years ago, there was a large pet trade in Dumeril’s Monitor. They are very difficult to find in the wild and rather hard to breed in captivity, and so it is now often hard to find a Dumeril’s Monitor for sale.

Compared to other Monitors the Dumeril’s Monitor is relatively non-aggressive. But they are relatively aggressive when compared to other lizards in general. Aggression levels will vary between individuals, and like other lizards, an individual’s temperament often reflects factors such as the amount of handling they receive and length of time in captivity; but like all monitors they are predators and their behavior does reflect this. Because Dumeril’s Monitors are very secretive animals, it is unknown whether the animal is common or rare. In fact, very little about the Dumeril’s Monitor is known. They usually make their homes in wooded areas near swamps or other bodies of water. They feed primarily on crabs, although if crabs are not available they may also eat insects. It is believed that Dumeril’s Monitor is specially adapted to eat crabs: they puncture the shells with sharp, scant teeth and swallow the meat whole. Some researchers have said that wild Dumeril’s Monitors eat birds, green turtle eggs, and ants. These claims cannot be proven or disproved. There has been no observation of Dumeril’s Monitor hatchlings in the wild. Hatchlings born in captivity resemble King Cobra hatchlings, which may be an attempt to mimic an unappetizing animal. Captive hatchlings often bury themselves or spend much of their time on the branches of trees. Excellent swimmers, Dumeril’s Monitors are also adept at climbing. They spend large portions of their day asleep in tree hollows and crevices between rocks. They may be habitual animals, returning to the same place daily to sleep and eat. Dumeril’s Monitors, mostly the males, will fight by standing on their hind limbs with their front limbs on the other’s shoulders, trying to push each other over.

Dumeril’s Monitors are relatively large lizards, often reaching five feet in length. As hatchlings, they are very colorful with bright orange heads and yellow patterns traversing their black bodies. The hatchlings also have a vertical mouth band. As they mature, the colors fade to shades of olive, and the black changes to olive-brown.

A French herpetologist who lived between 1774 and 1860 was the first person to describe Dumeril’s Monitor. This man, A.M.C. Dumeril, lent his name to the species. They live in Southeastern Asia, including Burma, Thailand, Malaya, Vietnam, Borneo and Laos. Because they are difficult to breed in captivity, Dumeril’s Monitor is often difficult to acquire as a pet, however, the Buffalo Zoo has a pair that they have successfully bred several times.


White’s Dwarf Monitor (Varanus baritji)
March 1, 2008, 11:47 pm
Filed under: Monitors, varanus | Tags: , , ,


This Australian dwarf species looks very similar to V.acanthurus. Even experts have been wrong in the past. The biggest difference between these two species are their markings and pattern. The easiest way to tell the difference is by close comparison. V.baritji lacks the light and dark dorsal neck stripes and the ocellated markings on the back in comparison to V.acanthurus.

White Throated Monitor – Varanus albigularis
March 1, 2008, 11:41 pm
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Scientific name: Varanus albigularis albigularis
Family: Varanidae
Order: Sauria
Class: Reptilia


The White-throated Monitor has a large and muscular body, an elongated head with a dome-shaped snout, short sturdy limbs, and a strong, thick tail. The length of the tail slightly exceeds the sum of the animals head and body lengths. Furthermore, the tail functions as a prehensile organ, a rudder, and as a weapon. The front legs are surmounted with long, sharp claws that enable this lizard to dig and climb. White-throated Monitors are adept climbers. As common to all Varanidae, they have long, forked tongues. The tongue is not only used for drinking but also in a sensory capacity. It is a common myth told to tourists that the White-throated Monitor lizards suck milk from cattle udders. The adult White-throated Monitor can attain lengths up to 120 to 150 cm (4 6 ft.) from the tip of its snout to the end of its tail. The average weight of the adult male is 8 kg (17.5 lbs). The adult female has an average mass of 6.5kg (14 lbs.) In captivity, both sexes tend to become obese, weighing up to 20 kg (44 lbs). An ivory-colored throat is the distinguishing characteristic of this monitor. Its body is covered with 110 to 140 small, beadlike scales that form reticulated and banded patterns of gray, brown, and black, intermingled with conspicuous yellow and/or white patterning.


The White-throated Monitor is found throughout Central and Southern Africa. The White-throated Monitor is both terrestrial and arboreal. It inhabits the savanna, steppe, open bush, and woodland regions. However, it is not generally found near water sources. This monitor has a large home range relative to its body size. The home ranges of males average 18.3 square kilometers (approx. 7 sq. miles), whereas the home ranges of females average 6.1 square kilometers (approx. 2.5 sq. miles). Researchers have shown that the home ranges of both sexes do indeed overlap.


The White-throated Monitors are essentially solitary individuals. They generally ignore each other until the mating season. These monitors are diurnal. Reproductive males and females will fully utilize their home range foraging during the wet season. Only the males roam their home ranges during mating season, whereas the females remain in one particular location of their home range. Throughout the remainder of the year when prey populations are low to nonexistent, both sexes limit their daily movements and remain basically sedentary so as to conserve energy. It should be noted that the White-throated Monitor will not attack humans unless provoked. When threatened, the White-throated Monitor will assume an intimidating posture by arching its neck, puffing out its throat, and hissing loudly. It will then lash out with its tail and bite violently at anything within its reach. This monitor is a formidable opponent. As a last effort, it will allow itself to be attacked. When its foe leaves it for dead, this monitor is able to survive because it is able to rapidly recuperate. White-throated Monitors have been noted to fight to the death. The main competitor of the White-throated Monitor is the black-backed jackal, as both have similar diets. Predators of this monitor are ratels, birds of prey, and most large carnivores.


The White-throated Monitor is a voracious feeder between the months of January to February, also known as the wet season. It will travel long distances in search of prey. During the dry season from July to December, it fasts losing approximately 4% of its body weight per month. Research has shown that this monitor has an adaptive relationship between its feeding habits and digestive responses similar to sit-and-wait foraging snakes. This adaptation serves to conserve energy during the long interval between meals. Its diet in the wild ranges from invertebrates, small reptiles, birds and eggs to occasionally small mammals and carrion. Land snails are the favorite prey. Studies have shown that it uses visual and chemical cues in distinguishing its prey. This monitor is a selective feeder. It seeks to obtain the highest caloric intake at the least energy expense of handling time despite the availability of other prey choices. The White-throated Monitor does not chew its food, but instead swallows small prey or large pieces of prey whole by increasing the size of its mouth. This is accomplished by spreading the hyoid apparatus and dropping the lower jaw.


White-throated Monitors are oviparous. In the wild, females will produce one clutch of up to 50 eggs. However in captivity, females will lay multiple clutches per year. During the cool, dry season from May to August, the male will go on a tour of his home range six weeks prior to mating. He will visit the locations of reproductive females. The male exhibits the same behavior patterns as when foraging. During this period, the females remain relatively stationary, preferring to remain upon elevated sites, such as trees and rocks. During this period of touring, it appears that feeding or mating does not occur. The male seems to remember the locations of the fertile females and will return to mate with them at their optimum time. During the courtship, the male will wipe his mouth on elevated objects immediately adjacent to the female and display vent dragging. He will make exaggerated, spasmodic movements as he approaches the female. The response of the female is to flatten her body and press her head down to the ground. Before actual contact, the males will flick his tongue around the females mouth, hind legs, and the base of her tail. The female remains passive during courtship and mating; therefore, there is no aggression between the sexes. White-throated Monitors prefer to copulate in trees. Intruding males will be chased away by the resident male. Researchers did not observe any ritualistic combat between males. Both sexes will mate with multiple partners. The female lays her eggs in a nest in an abandoned ground squirrel burrow. The eggs are covered and left to hatch. Egg laying usually occurs two months prior to a significant rainfall. The eggs are turgid and possess a high water content. The hatchlings emerge throughout the rainy season and feed primarily upon invertebrates. During the next three months, they will triple their mass and double in body length. In the wild, less than half of the hatchlings will survive. White-throated Monitors are reproductive at 3 – 5 years of age. Their life expectancy is about 15 years.


This species of monitor is classified as threatened by CITES under Appendix II. The greatest threat to White-throated Monitor populations is habitat destruction and fragmentation. The native inhabitants hunt the White-throated Monitor for its alleged medicinal properties. This animal is also hunted for its hide and as a food source. This species, as well as all monitors, are sold worldwide as part of the exotic pet trade. One of the unfortunate consequences of the illegal export/import of monitors is the spread of parasites. Three species of African ticks parasitize the White-throated Monitor: Aponomma exornatum, Aponomma flavomaculatum , and Aponomma latum. These ticks are vectors of the deadly heartwater disease, which is a serious threat to domesticated animals. Recently, this disease afflicted sheep, cattle, and deer in Florida. Monitor ticks are also vectors of Coxiella burnetti, a Rickettsiales agent responsible for Q fever in humans. Q fever is characterized by fever and pneumonia-like symptoms. It is rarely fatal.

All of Varanus Species
March 1, 2008, 11:37 pm
Filed under: varanus | Tags: ,
Latin name: Dutch name: English name: German name:
Varanus acanthurus Stekelstaart varaan Spiny-Tailed goanna / Ridge Tail monitor Stachelschwanzwaran
Varanus albigularis Witkeelvaraan White-throated monitor Kapwaran
Varanus auffenbergi   Peacock monitor / blue Timor monitor  
Varanus baritji   WHITE’s dwarf goanna  
Varanus beccarii Zwarte boomvaraan Black tree monitor Schwarzer baumwaran
Varanus bengalensis Bengaalse varaan Bengal monitor Bengalwaran
Varanus boehmei Goudgevlekte boomvaraan Golden Speckled Tree monitor Goldgefleckter Baumwaran
Varanus bogerti Bogert’s varaan Bogert’s monitor Bogertwaran
Varanus brevicauda   Short-tailed goanna  
Varanus bushi      
Varanus caeruliverens Turkoois varaan Turquoise / Blue pinspot monitor  
Varanus caudolineatus Streepstaartvaraan Stripe-tailed goanna  
Varanus cerambonensis   Ambon monitor  
Varanus doreanus Blauwstaartvaraan Blue-tailed monitor  
Varanus dumerilii Dumerili varaan Dumeril’s monitor Dumrilwaran
Varanus dwyeri      
Varanus eremius   Pygmy desert goanna  
Varanus exanthematicus   Bosc’s monitor lizard Steppenwaran
Varanus finschi   Finschi’s monitor  
Varanus flavescens   Yellow monitor / Short-toed monitor Gelbwaran
Varanus giganteus   Perentie Perentie
Varanus gilleni   Gillen’s goanna / Mulga monitor  
Varanus glauerti Glauert’s varaan Glauert’s goanna  
Varanus glebopalma   Twilight goanna / Long tailed rock monitor  
Varanus gouldii Gouldsvaraan Gould’s goanna Gouldswaran
Varanus griseus   Grey / Caspian / Indian desert – monitor Wstenwaran
Varanus indicus Mangrove varaan Mangrove monitor Pazifikwaran
Varanus jobiensis   Sepik monitor / Peach-throated monitor  
Varanus juxtindicus   Rennell island monitor  
Varanus keithhornei Blauwneusvaraan Blue-nosed goanna / Canopy monitor Queensland-baumwaran
Varanus kingorum   King’s goanna  
Varanus komodoensis Komodovaraan Komodo Dragon Komodowaran
Varanus kordensis      
Varanus mabitang   Panay monitor  
Varanus macraei   Blue tree / Mac Rae’s monitor  
Varanus melinus Gele boomvaraan Quince / Yellow monitor lizard Quittenwaran
Varanus mertensi Mertens watervaraan Mertens’ goanna Wasserwaran
Varanus mitchelli   Mitchell’s goanna  
Varanus niloticus Nijlvaraan Nile monitor Nilwaran
Varanus olivaceus   Gray’s monitor Olivwaran
Varanus ornatus Nijlvaraan Ornate monitor Nilwaran
Varanus panoptes   Argus monitor Arguswaran
Varanus pilbarensis   Pilbara goanna  
Varanus prasinus Smaragd varaan Green tree monitor, Emerald monitor Smaragdwaran
Varanus primordius   Blunt-nosed goanna  
Varanus reisingeri Gele boomvaraan Yellow tree monitor  
Varanus rosenbergi   Rosenberg’s goanna Schwarzer Sandwaran
Varanus rudicollis   Rough-necked monitor Rauhnackenwaran
Varanus salvadorii   Salvadori’s monitor / Crocodile monitor Papuawaran
Varanus salvator Watervaraan Water monitor Bindenwaran
Varanus scalaris Gebandeerde boomvaraan Banded tree goanna  
Varanus semiremex   Rusty goanna  
Varanus similis   Spotted tree goanna  
Varanus spenceri   Spencer’s goanna Spencerwaran
Varanus spinulosus   Keeled Monitor Lizard  
Varanus storri   Storr’s goanna  
Varanus telenesetes   Rossel island monitor  
Varanus timorensis Timorvaraan Timor monitor Timorwaran
Varanus tristis   freckled / mournful / black-headed -goanna Trauerwaran
Varanus varius   Lace monitor Buntwaran
Varanus yemenensis   Yemen monitor  
Varanus yuwonoi   Tricolored monitor  
Varanus zugorum      

Black Tree Monitor (Varanus Beccarii)
February 22, 2008, 4:34 am
Filed under: Monitors | Tags: , , , ,

Adult Back tree monitors are completely black in color, while young offspring tend to exhibit lighter shades of green. Like other monitors, Black tree monitors have long, sharp claws and strong jaws. Their teeth are longer than the other monitor species, which enables them to hold on to prey they catch high up in the canopy. They are often sold as pets and do well in captivity with a heat lamp, as long as temperatures maintain 85 degrees Fahrenheit, with a basking temperature of 100-110 degrees Fahrenheit.


Black Tree Monitors are carnivorous(meat eaters). In the wild, Black tree monitors eat snails, grasshoppers, beetles, scorpions, birds eggs, fish, other lizards, snakes, nestling birds, and shrews. In captivity the Black tree monitor eats crickets, roaches, mealworms, ground turkey and cat food.

Social Structure: When threatened monitors inflate their neck and hiss at an intruder. Their ribs may spread out a bit as the monitor takes in air to inflate its body. This makes the monitor appear larger to its enemy. Unlike other monitors, the Black tree monitor does not use its tail to lash at intruders. The black tree monitor is very quick and agile and can often escape its enemies by rapidly climbing trees. They may resort to biting and clawing, as a means of defense if their escape is not successful. Monitors are daytime lizards and spend most of their days living in treetops or swamps in search for food.

Senses: Black tree monitors, like all reptiles, are ectothermic (cold-blooded animals.) They have leathery, dry skin and are unable to produce their own body heat, so they must rely on basking in the sun for warmth. Monitors have excellent eye-sight and can sense movement from as far as 250 meters away. They also have a tongue like a snake. This fork-like tongue provides them with the superior sense of smell by bringing sent particles into their mouth, so they are able to taste what other animals can only smell. This special sense allows monitors to locate food, a mate, or an enemy.

This black monitor is one of the few monitor species with the ability to use its tail as a fifth limb. Closely related species are V.prasinus, V.boehmei, V.bogerti, V.keithhornei, V.macraei, V.telenesetes and V.reisingeri.

Varanidae (Monitor Lizards)
February 22, 2008, 4:28 am
Filed under: Monitors | Tags: , ,

  • Monitor lizards live everywhere it seems, from the African Continent, spread across all over Asia and all through Indonesia.
  • Monitors have a high metabolic rate, and are capable of actually catching their own prey as opposed to scavanging. It is of recent discovery that they may have a low bit of weak venom. This lead to the hypothesis that all venomous lizards are dirived from one common venomous ancestor.
  • The word Varanus derives from the word Waral which in Arabic translates back to English as Monitor. Legend has it that these lizards warned people when crocodiles were nearby.
  • Varanids are very intelligent, and some species are even clever enough to count.  In studies done at the San Diego Zoo, varanids were able to count the number of snails they were eating, up to six.Komodo dragons recognize feeders and have different personalities.
  • The most commonly kept monitors are the savannah monitor, white throated monitor, and Acklin’s monitor, due to their relatively small size and ease of domestication. Nile monitors, water monitors, mangrove monitors, and papau monitors have also been kept in captivity. Like all reptiles that are kept as pets, monitors need hiding places, and an appropriate substrate (bedding). Monitors also need a large water dish in which they can soak their entire body. In the wild, monitors will eat anything they can overpower, but crickets, superworms, and the occasional rodent make up most of the captive monitors’ diet. Boiled eggs, silkworms, earthworms, and feeder fish can also be fed to monitors. Monitor lizards have been compared to reptilian cats – independent animals with different personalities. However, due to their predatory nature and large size some monitors can be dangerous to keep as pets. Adult nile monitors can reach seven feet in length, and are stronger than an alligator of equal weight.

Spiny Tailed Monitor General Information (Varanus Acanthurus)
February 22, 2008, 4:18 am
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The Spiny-tailed Monitor or Ridge-tailed Monitor (Varanus acanthurus) is a small species of monitor lizard. They are native to Northwestern Australia and live in a variety of habitats from arid to tropical regions. Spiny-tailed Monitors are usually a reddish brown with yellow markings but color and pattern can vary with geographic origin. A distinctive feature is their thick spined tail – hence their common name. This tail is used for both attacking prey and for protection from predators. When attacking prey the tail is used like a whip, stunning the prey item which is then consumed without expending further effort. When used in defense, the Ridge-tail will scramble into loose rocks or boulders and use its tail to wedge itself in tight. The spikes give the tail good grip on the rocks, making extraction by other predators nearly impossible. In the species’ home territory, the tail is often found discarded near Ridge-tail carcasses, indicating that predators of this species consider the tail inedible.