Animal Information

The Savannah Monitor (Varanus exanthematicus)

The Savannah Monitor is an Intelligent and appealing reptile. They are listed as appendix II on Cites. Because they have been heavily exported for the pet and leather trade. The good news is, they are listed as Least Concern. Because they breed prolifically and there are poor record keeping on the part of exporters. The species has not been updated on the IUCN Redlist since 2009.

The Savannah monitor (Varanus exanthematicus) is a medium-sized species of monitor lizard native to Africa, found in Senegal east to lower Sudan and western Kenya. These lizards inhabit sparse grasslands that are seasonally dry and desolate.

The specific name exanthematicus is derived from the Greek word exanthem /ɛkˈsænθɪm/, meaning an eruption or blister of the skin.

Lifespan: 10 to 15 years.

Originally described as Lacerta exanthematica, in reference to the large oval scales on the back of its neck. The species is known as Bosc’s monitor in Europe since French scientist Louis Boscs. It belongs to the subgenus Polydaedalus, along with the Nile, the ornate and other monitors.

The Savannah monitor is often confused with the white-throat monitor (Varanus albigularis). Until 1989 the white-throated monitor and the savanna monitor were considered to be the same species.

The white-throat monitor can grow to lengths of 5–6 ft.

While the Savannah growing to 4 feet and a few exceptional monitors growing to 5 feet. Still, similar in overall appearance, this species possesses significant morphological and ecological differences and is recognized as a very distinct species.

With 5 subspecies described, the skin coloration pattern of the Savannah monitor 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 halfway from the eyes and the tip of the snout.

Varanus exanthematicus feeding habits revolve around the weather. They use a feast and fast system. They feast during the wet season when food is plentiful and easy to find.

This wet season lasts for about eight months, during which V. exanthematicus can consume up to one-tenth of its own body weight in a single day. During the dry season they then live off the fat reserves they built up over the “feast season”.

Information about the diet of Savannah monitors in the wild has been recorded in Senegal and Ghana. It feeds almost exclusively on arthropods and mollusks.

In Senegal, Iulus 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. While orthopterans, scorpions, and amphibians were the most common prey of animals 6–7 months old.

Savannah monitors have evolved a way to eat poisonous millipeds: The lizard rubs its chin on the millipede for up to fifteen minutes before eating it. It is believed to do this to make the millipede excrete the distasteful fluid in its defense and then it will eat it when the supply of this fluid is exhausted.

Many adults also consume large quantities of snails. Full grown V. exanthematicus have evolved teeth that give maximum leverage at the back of the jaw to crush snail shells.

In general, wild Savannah monitors are both active hunters and scavengers. The majority of their diet consists of insects (roaches, termites, scorpions, millipedes), birds, eggs, other reptiles, and rodents. The captive diet should be similar, with an emphasis on invertebrate food sources.

Monitor lizards’ fork-like tongues allow them to taste the air, which in turn lets them detect movement and prey.

Taste buds on their tongues, as well as organs near the tip of their nose, allow them to almost triangulate the location of a small depending on which side of the tongue they are locating a scent.

Savannah Monitors have a calm personality. However, this is a
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Young monitors will enjoy a staple diet of appropriately sized mealworms, waxworms, and feeder roaches.

Avoid feeding young monitors rodents, as young, unweaned mice are very high in fat, but low in other more valuable nutrients.

Older monitors can receive rodents occasionally as part of a balanced diet.

Keep in mind that these animals are simply not designed to digest large quantities of fur and fat, and the constraints of a captive lifestyle can only compound potential issues.

Surprisingly, even one or two rodents a week could be too much for this species.

Even adult Savannah monitors should be fed lots of insects. A colony of large roaches (such as Discoid roaches) would be a good investment, and if properly maintained, should provide a constant supply of food items for your lizard.

Crickets and larger mealworms will also be consumed. A mixture of ground turkey, raw egg, and a suitable calcium/vitamin supplement has proven very successful in both the private sector and among zoos for maintaining large, carnivorous lizards.

As long as careful attention to supplementation and variety, this mixture can make up as much as half of the lizard’s staple diet.

All food items, with the exception of rodents and pre-mixed diets, should be regularly dusted with a high-quality calcium/vitamin D3 supplement.

Food for growing monitors should be dusted several times a week, while less frequent supplementation is acceptable for older lizards.

A good multivitamin should also be employed, and as formulas differ, follow the manufacturers directions for dosage information.

It should be noted that Savannah monitors are particularly prone to obesity and subsequent medical problems. Poor diet, coupled with lack of room to exercise quickly result in an overweight monitor. Avoid overfeeding, try to replicate the natural diet, and provide ample space to avoid these problems.

This is not a pet for an amateur herpetologist. Savannah monitor lizards are popular pets in the United States but don’t always thrive in captivity. Very specific conditions are required to keep these lizards healthy. 

Housing Savannah Monitors…

It Sounds Easier Than It is…

A juvenile (young) Savannah will be fine in a 55-gallon aquarium for a short period of time, but since they grow quickly, most owners have their adult set-up ready when they bring home a baby.

Outdoor enclosures are best. However, it is possible to achieve optimal conditions indoors.

A large, secure enclosure is necessary to house any Savannah monitor. A full-grown savannah needs a minimum of an 8-by-4-feet enclosure or twice the length of the monitor.

The height of the enclosure should prevent them from escaping and allow a branch or other decoration in the cage on the off chance they want to climb. Monitors can be destructive, so other than some rocks and hides, decorations aren’t necessary.

A large water dish that will allow the entire monitor to submerge itself should be in the cage as well. A large cat litter box is a popular alternative to reptile dishes sold at the pet store. We use concrete mixing tubs whenever possible. They usually defecate in their water dishes, so make sure the water stays clean.

Screen-sided enclosures are unacceptable due to large nails. Make sure the cage has a secure lock and a place for heat lights and UVB lighting on top.

24 inches of soil and sand mixture is recommended in order for a Savannah to forage around. Remember to try and mimic their native environments.

At one time, keepers kept the Savannah monitor in dry, arid, and hot desert conditions. Now this reptile is being successfully kept with more humidity and areas to burrow, just like the natural grasslands of Ghana.

Provide a warm temperature of 95 to 100 F and a basking spot between 110 and 130 F (but sometimes even higher, according to some owners). Along with a temperature gradient down to 85 F in the day and as low as 75 F at night. Ceramic heat emitters are better than lights for achieving nighttime temperatures.

Savannah monitors are diurnal and most active when the sun is out and it’s warm. In cooler weather or periods of drought, these lizards become mostly dormant.

These lizards are prone to parasitic infections. The symptoms of an internal parasite include sluggishness, lack of appetite, and vomiting.

They’re also frequently afflicted with external parasites, or mites, that suck the lizard’s blood through the skin. Both of these conditions are potentially life-threatening and unfortunately common in Savannah lizards kept in captivity. 

Like many reptiles, Savannah monitors are also susceptible to respiratory infections. Open-mouthed breathing, wheezing, and mucus in the mouth are the most common symptoms. All medical conditions require a visit to a reptile veterinarian for treatment.

Sexing Savannah Monitors

Visual Difference

While judging by size alone is not recommended, male savannah monitor lizards usually possess bigger heads than the females, but not by much. Mature savannah monitors sometimes grow to around 5 feet long and can weigh upward of 154 pounds but are often much smaller than that.

Interestingly, females have bigger eyes and nostrils.

Presence of Hemipenes

One key sign of a male savannah monitor is the presence of hemipenes, which are reproductive organs situated on their tails’ foundations. They look like a pair of small pink tubes with what can be described as a spiky flower ball at the end.

Sometimes, a male will evert his hemipenes, pushing them out and dragging them along the ground in a dominant or territorial display.

Females can and rarely do evert their sex organs which look like small pink/purple tubes with no spiky/flower at the tip. This can be seen very early on which they are still babies but rarely displayed.

Red Specks

Although female savannah monitors lack hemipenes, they do have tiny red specks that flank their excretory openings. The presence of these specks is an indication that you’re dealing with a girl rather than a boy. These are usually much easier to see than the hemipenes of the boys, as they’re in an external location.

Breeding Savannah Monitors

It Sounds Easier Than It Is!

Savannah monitor males are quite territorial and will defend their territory very aggressively. They show their aggression with loud hissing sounds and trashing the tail, before striking at their opponent. If need be they will wrestle and bite each other and can inflict quite severe injuries to each other.

A mature pair of Savannah monitors should be at least 1.5 years old or more. Sexing monitors can be tricky, even for experts. Males tend to have large post-cloacal bulges formed by the stored reproductive organs, but female monitors also have long, retractable structures.

A healthy female Savannah monitor ready to mate gains weight as eggs develop. You should feed adult monitors three or four times per week, and offer gravid females food more frequently. The females require a higher dose of calcium and vitamin D3 to help with egg production.

In the early stage, female Savannah monitors are receptive to mating, and males are aware of this timing. Mating may take place briefly on one day or be prolonged over several.

The male mounts the female’s back, and their tails contort so the cloacas are next to each other. Actual copulation may take several minutes or an hour. Males should be separated from females after mating occurs.

Shortly after mating, the female Savannah monitor starts digging test burrows until, some three to four weeks after mating, she excavates one into which she lays her eggs.

The average clutch is between 12 and 20 eggs, but some monitors have produced as many as 41. When she is finished, she fills in the nest and ignores the eggs.

At this stage, you must carefully unearth the eggs, and remove them to a safe incubator. If eggs are left in the terrarium, it is possible that one of the adults will eventually dig them up and eat them. Be careful not to turn or rotate when removing the eggs. Turning a reptile egg may suffocate and kill the embryo.

Eggs may be placed in small plastic containers with about half an inch between each egg as well as between the eggs and the sides of the container.

Place the container in a warm, dark place, such as a large commercial incubator or a dedicated closet, and keep them at a constant temperature of 78 to 88 degrees Fahrenheit.

Hatchlings arrive in five to six months. The entire clutch of young Savannah monitors tend to hatch within hours of each other. Moreover, the eggs of V. exanthematicus have an unusually high hatch rate of nearly 100 %. Much as their turtle cousin the African Sulcata Tortoise.

The Tongue Tied Lizard

All monitor species have forked tongues. Monitor lizards, like snakes, have a pair of sensory organs located above the roof of the mouth called the Jacobson’s organs.

The organs are used to detect scent particles within the air.

These lizards continuously flick their forked tongues to collect these particles and to ‘taste’ the air; this extra sense is used mainly for hunting as monitor lizards are very active predators and are almost constantly foraging around for food.

During the breeding season, it is also used to help these usually solitary reptiles find a mate; the male will use his tongue to follow the scent of a female.

The duration of poststrike elevation in tongue-flicking (PETF) in the savannah monitor, Varanus exanthematicus, is experimentally estimated to be at least 25 min, with some residual increase persisting for at least 30 min.

This is by far the most prolonged PETF yet observed in a lizard, as predicted from the active foraging on mobile prey and the chemosensory specializations of the varanid tongue. PETF is shorter than in rattlesnakes, presumably because prolonged search is more likely to be successful when the prey has been envenomated.

Strike-induced chemosensory searching, which consists of both PETF and searching movements, appears to be of shorter duration than PETF because searching movements do not last as long as PETF. Individual lizards differ markedly in the duration of tongue-flicking and the degree of increase in tongue-flicking attributable to biting prey.

Individuals tongue-flick at their own highest rates in the first minutes after stimulus presentation, then show a decline, often to zero. Some individuals resume tongue-flicking, sometimes at high rates, after having stopped for one to several minutes.

Such behavior may aid in the relocation of escaped prey that has reemerged after the initial chemosensory search has failed or in the location of similar prey likely to be in the vicinity if patchily distributed.

Conservation Notes:

The Savannah monitor 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.

Often 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.

Nevertheless, the vast majority (estimated 90%) 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.

V. exanthematicus is listed as least concern by IUCN.

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 global conservation concern due to the vast range of the species. In addition to the fact that collection for the pet trade often occurring in a relatively small area.

In the past, Savannah monitors were imported to the United States and Europe in massive numbers.

Often resulting in dehydrated, starving animals that failed to thrive.

An average of 30,574 live specimens was imported into the US each year between 2000 and 2009. The total imports of live specimens in 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.

On the other hand, the total worldwide declared exports of skins were reported to be 37,506. Remember, substantial undeclared trade in the species occurs from Sudan, Nigeria, and elsewhere.

Luckily, with the recent interest in conservation within their countries of origin, these monitors are being “ranched,” that is being bred and/or hatched in controlled environments in their native land.

As a result, healthy babies are now widely available, as are animals bred here in the States by a few dedicated hobbyists.

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).

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