Reptiliana: Ultimate Reptile Resource

Mangrove Monitor Lizards
March 21, 2008, 8:40 pm
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Varanus Indicus. Varanidae/ Sauria / reptilia

LENGTH: Varanus indicus ranges from 75 to 120 cm in length. The head is long and narrow, with the neck longer than the head. The tail is almost two times the length of the body and strongly compressed.
COLORATION: dark colorations with various small, yellow spots. The iris is dark brown with a golden ring surrounding it, and the palpebrals that surround the eye are sulphur yellow while the remaining surfaces of the eyelids are white. Also, the mouth is sometimes outlined with red and this may attract prey or frighten predators. Komodo dragons show a similar coloration. The red substance is actually blood mixed with saliva.
The Mangrove Monitor has four strong, well developed legs with five, sharp, clawed toes. TEXTURE: The face is smooth and glossy, with large scales. The body and tail are covered with small, oval, keeled scales. The teeth are serrated along their anterior and posterior edges, with the dentary teeth directed slightly laterally and the maxillary teeth directed vertically.
COOL FACTS: A special characteristic of this monitor is that it possesses the ability to greatly increase the size of the mouth by spreading the hyoid apparatus and dropping the lower jaw in order to eat large prey. Another special characteristic of this monitor is that they have no taste buds on their tongue, but they may have taste buds on the roof of their mouth. Although the tongue has no taste buds, it is highly specialized for chemosensory function and is frequently protruded.

HABITAT: Varanus indicus occurs in the Pacific from Japan to southern Australia and on many of the islands of the Pacific. Man-aided dispersal from the East Indies to some small pacific islands was facilitated by Polynesians in order to provide a meat supply. It is not known whether all these island locations were natural or man-aided dispersal. The monitors were also introduced to Japan from the Japanese in the Marshall Islands before World War II. The habitat of V. indicus consists of damp river banks and in coastal forests.

BEHAVIOR: The Mangrove Monitor can be characterized as being an “opportunistic predator” as far as feeding behavior. A study done in 1993 showed that V. indicus in the Southern Mariana Islands shifted major prey classes reflecting changes in the available prey base. The following regular prey of V. indicus have been declining: A land snail, Achatina fulica , has been greatly reduced due to the introduction of the predaceous flatworm, Platydemus manokwari, populations of slugs have been greatly reduced because of the introduction of the Cane Toad, Bufo marinus, and the shrew populations on Guam are low because of the introduction of the Brown Tree Snake. When V. indicus have been observed in captivity, males tend to be more aggressive than females, and if males feel threatened, they don’t bite, but rather defecate on the perceived threat. No courtship behavior has been observed. In one observation, after mounting the female, the male used his chin to rub the dorsum of the female’s head and forequarters. It was also observed that while mounted and oriented head to head, the male and female slowly rotated in a clock-wise direction through 360 degrees with the male remaining superior. They are extremely shy animals.

DIET: The diet of V. indicus consists of small mammals, insects, crabs, bird eggs, birds, and other lizards. A study done in the Northern Mariana Islands and the Territory of Guam between the years of 1989 and 1991 showed the diet of V. indicus, in non-urban settings, consisted of 45% arthropods, 13.6% terrestrial crabs, 27.2% scincid and gekkonid lizards and their eggs, 4.5% of Ramphotyphlops braminus, and rats made of the rest of the diet, at 9.1%. In urban situations, additional food in their diet included domesticated chicken eggs, squid (a common fishing bait), and aluminum butter wrappers.

REPRODUCTION / GROWTH: The clutch size of female V. indicus is about 2-12 eggs, and is smaller than would be expected of a medium sized monitor lizard because female V. indicus are very small. A female observed in Guam laid 22 eggs over a period of three years in clutches of 1-4 eggs. A captive female laid 25 eggs in five clutches over 26 months, with an average of 88 days between the last four clutches and 4-6 eggs in each clutch. The varied clutch sizes indicates that the monitors tend to reproduce continuously when food is abundant, producing large numbers of relatively small clutches. The eggs are about 3.5 – 5 cm in length, are oblong and white, and hatch in about seven to eight months. No care are given to the young by the parents when they hatch. Guam is the only place where a nesting site has been seen, and it was found in guano deposits of a cave-dwelling bird, Aerodromus vanikorensis. The site contained only egg shards. A characteristic of courting exhibited by males involves showing both physical and behavioral control over the female. Males also fight for females. A study done in 1998 looked at the reproductive ecology of V. indicus on Guam. Adult lizards acquire energy stores in the form of fat bodies to meet energy demands during reproduction. In females, stored fat is mostly used for egg production, but in males, the use of fat is not well understood but it could be used for a variety of activities, including reproductive behavior, such as searching for females, courting, mating, and territorial defense, rather than just for spermatogenesis. The results of this study showed that ovarian mass is greater during the dry season for females, the minimum body size at sexual maturity is greater in males than females, and that males have testicular sperm year-round. Fat body mass in males did not differ between seasons, but female fat body mass was greater during the dry season than during the wet season. Reproduction of V. indicus on Guam seems to occur during the dry season (January to April). The reproduction occurring during the dry season can be explained by looking at egg incubation periods and food availability for juveniles. When the young hatch during the wet season, insect abundance is greater, meaning more food for the young.

CONSERVATION STATUS: There is no entry on the Red List 2000 for V. indicus . The major populations of V. indicus include Australia, Guam, Indonesia, Japan, the Marshall Islands, Micronesia (Federated States of), Northern Mariana Islands, Palau, Papua New Guinea, and the Solomon Islands. In 1994, there was a decline of V. indicus on Guam and the Mariana Islands that could have been due to the effects of urbanization. Also, farmers on these islands see the monitors as pests and try to trap, shoot and poison them because they have witnessed the monitors attacking their domesticated fowl. There is an ethnic group on Guam that eat the monitors as a traditional food, so a business exists to sell the monitors to them. The introduction of the Brown Tree Snake, Boiga irregularis, and the poisonous Cane Toad, Bufo marinus , are also known to affect the monitor population on these islands. Lastly, the mangrove monitor has a beautiful skin and as a result is hunted in many places for its leather. There were CITES export quotas in 1997 and 1998 in Indonesia.

Quince/ Yellow Monitor (varanus melinus)
March 21, 2008, 8:31 pm
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Varanus melinus is a member of the subgenera Euprepiosaurus. It is very close related to V. indicus, but it is very easyly to be distinguished by the yellow coloration.

LENGTH: This species can reach a total length of 80-120 cm.
COLORATION: The coloration of the head, back, legs, and tail is a bright yellow. A black reticulation starts at the lower third of the neck and is most prominent at the body. There some yellow spots, sometimes forming yellow ocelli, are ordered in regular cross row over the back. The tail is banded alternately black and yellow on the first two thirds, getting more pale in the lower third. The underside from head, throat, body, legs, and tail uniformly pale yellow, only on the throat a light black reticulation is visible. 124-130 scales are around midbody. The nostril is situated closer to the tip of the snout than to the eye. The tongue is uniformly light pink.

DISTRIBUTION: restricted to the the island of Obi in the Moluccas, Indonesia. But because these data are only known by the dealer, who shipped some animals over to Germany and the USA, it is no sure, that it is correct (BÖHME & ZIEGLER 1997). It is also reported, that V. melinus might occur on the Sula Islands, western Moluccas. V. melinus also might occur on Taliabu, Bowokan, and Banggai Island.

FOOD/ HABITAT: Meat almost any kind, eggs (cooked so the risk of Salmonella is lowered), mice, rats, crickets (when small), fish, giant meal worms and I have found that canned cat food is similar enough to the canned monitor/tegu food to be fed. They are scavengers also so if you see that they don�t eat right away don�t be alarmed. I feed her twice a week but it can vary on size and what you are giving, if you give a big meal don�t feed them the next day if it�s a small meal maybe feed in another day or 2.

IN CAPTIVITY: Because Varanus melinus became known to the public and science only some years ago (BÖHME & ZIEGLER 1997) only very little is known of the captive husbandry of this monitor lizard.
DEDLMAR & BÖHME (2000) desccribed the first capive reproduction of this monitor. They kept 2.4 specimen in several enclosures, each measuring 180 x 110 x 200 cm with a water basin measuring 125 x 110 x 50 cm. The side and the back walls are covered with cork plates. Some big trunks and some plastic plants are for climbing and shelter for the animals.
Mice and big locusts build the major diet for the monitors. Live fish were never taken, but fish fillets and prawns were always welcome.
In April 1999 one of the females laid two unfertile eggs. The same female laid again 6 eggs inAugust of the same year. All eggs were fertile and after an incubation of 168-171 days at an incubation temperature of 28.5°C five babies hatched. The other one just died about 10 days before hatching. The offspring had a total length of 210-220 mm and had a body mass of 21-23 g. Some days after hatching the youngsters started to feed on house crickets. About one month later the first pinkie mice were offerd and taken. No further problems were reported.

Can grow up to Five feet long in total. There are black spots on the body and the tail can be banded. The teeth are really shapr and can draw blood easily but the bites don’t hurt much.
They’re skittish and handling them can calm them down. Catching them wild might take them longer to calm down. They still want to run and hide.

They have long sharp claws that will scratch your arms. Tail whipping and bowel evacuation are also defense mechanisms. Males have hemipenal bulges and females don’t.

WATER NEEDS: A Large water dish big enough for them to swim in, which needs to be changed daily as they will get it filthy with dirt and feces. They love to dig and create burrows. 3 or 4 feet of soil or soil mix would be good. Include a hide box and include lots of branches. They love to climb. The bigger the tank/enclosure the better.

LIGHTING: I have a combination strip light with florescent and incandescent light bulbs. Never go over the suggested wattage of the light fixture. Day cycle should be on around 10-12 hours and the night cycle should allow for cooling, but not too much. The light bulbs should be ones made for reptiles so they get the added UVA/UVB that is important for proper health.

TEMPERATURE: A basking spot of up to 125 or more. The rest of the tank should be from around 95 to 80 and the humidity should be kept high.

Peach Throat Monitors (Varanus jobiensis)
March 16, 2008, 6:35 pm
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On the Island of New Guinea.

Blue tail monitor and the mangrove monitor. Each of the three use different parts of new guinea’s habitats.

Preferences: dense forests; for they’re excellent climbers.

Frogs, lizards, insects, any small animal they can overpower.

They can get up to 4 feet long in total length. They can live up to 15 years.

They take a while to tame and adjust in captivity, like most other lizards. The cage would need several hiding spots for security purposes. They should be maintained between 85 – 90 degrees with a basking spot of 95. At night temps shoudl be about 75. Bark or coconut bark is best, because it holds moisture well and duplicates the natural environment. Feed them mice, rats, fish, crickets, hardboiled eggs. Four or five times a week will ensure proper growth and health. Make sure to give them a calcium suppelement.

thanks to:

Peacock Monitor (Varanus auffenbergi)
March 16, 2008, 5:13 am
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Varanus auffenbergi

The peacock monitor was only described as a new species in 1999! But it’s not that different from Varanus Timorensis, or the Timor Monitor (Spotted Tree Monitor). The coloration and spot pattern as the only difference. The difference is the blue grey ocelli, whereas the Timors are creame colored, and they don’t have a pattern on their underside. The Peacock has some pattern on its bottom side. The color up top is dark grey. Numorous ocelli, (photoreceptor organs on animals; spots that sense light but not its direction). They have central spots, often light blue to grey. A red brown pattern is visible otherwise.
Strangely, these patterns fade after keeping in time in captivity.After this period, its hard to differentiate between the two.
In number, there are as many as there are Timors.

It’s length is up to 60 cm, or about 23.5 inches.The tail is relatively fat and round in cross section. Light scales form an irregular pattern.

The Peacock Monitor is mainly located on the island of Roti, Southwest of Timor.

In captivity they are relatively shy, but are not much different than taking care of the Spotted Tree Monitors.

Kimberley Rock Monitor – Varanus glauerti
March 1, 2008, 11:57 pm
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We’ve wanted these small monitors for some time and finally have them. Without a doubt, these are the most elegant small monitor around. There outgoing attitude makes them irrestible to anyone that has had the pleasure of handling one. They often run up your arm and sit on your shoulder when you open their cage door.

Yet another Australial gem. Kimberley’s are known to inhabit the extreme north of Western Australia and the Northern Territory. Their grace and beauty make them one of the most sought after varanids in the hobby. The color and pattern are rarely captured in photographs and need to be seen to be appreciate to the fullest.

This stunning monitor reaches 60-70 cm TL.

An insect and rodent based diet serves them well in captivity. Although sometimes a challenging feeder, kimberleys are worth the effort.

Our male and female are both very mellow and a joy to keep. When it comes to beauty, Kimberleys are second to none.

Their slender build and extreme contrast in pattern are sure to catch your eye and pique your interest.

Still very rare in private collections, this monitor is for the discerning keeper who wants to add rarity to their collection that will set them apart from the crowd..

Bosc’s monitor lizard – Varanus exanthematicus
March 1, 2008, 11:55 pm
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The Savannah Monitor (Varanus exanthematicus) gets its Latin name from the large, flat oval scales on the back of the neck which could be said to erupt, and its common name from the impression that it lives on the African savannah in the wild. The term savannah monitor is also used in reference to several other species of savannah-dwelling monitors. In the U.K. the species is often known as “Bosc’s Monitor Lizard.” It is a robust creature, with powerful limbs for digging, powerful jaws and blunt, peglike teeth. Maximum size is rarely more than 100cm. Its diet is much more restricted than that of other African monitor lizards, consisting mainly of snails, milipedes, orthopterans, beetles and other invertebrates. The only vertebrates regularly consumed are amphibians.

Its range extends from Senegal as far as Eritrea and northern Zaire. Varanus exanthematicus is primarily a ground dwelling species that shelters in burrows, although they are sometimes found in bushes or low trees. In the coastal plain of Ghana juvenile Varanus exanthematicus are often associated with the burrows of the giant cricket Brachytrupes.

This species is readily available in the pet trade. Juvenile animals are collected from several countries in West Africa (mainly Ghana, Togo, Benin and Nigeria) and exported worldwide. Animals sold as captive bred, captive farmed or ranched are the offspring of gravid females collected during the breeding season whose eggs are incubated by exporters. Adult specimens frequently become unwanted pets and are reported as being the most common monitor lizards by animal rescue agencies. However the vast majority die within a year of capture and captive breeding is very rare. The skins of the species are important in the international leather trade and originate mainly from Chad, Mali and Sudan.

Bosc’s Monitor is often confused with the Whitethroat Monitor (Varanus albigularis) which can grow to lengths of 5-6 feet. While similar in overall appearance, this species possesses significant morphological and ecological differences and is recognized as a very distinct species.

The salivary glands of many, if not all, species of monitor lizards produce venom in very low concentrations with vestigal function (Fry et al., 2006). The effect of these proteins on humans is negligible and the animals are not considered venomous. Complications arising from lizard bites are almost aways the result of infections.

Dumeril’s Monitor – Varanus dumerilii
March 1, 2008, 11:52 pm
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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
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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.

Black Tree Monitor (Varanus Beccarii)
February 22, 2008, 4:34 am
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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
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  • 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.