Savannah Monitor

“The savannah monitor is a medium-sized monitor lizard from sub-Saharan Africa.“

This voracious lizard eats as much as 10% of its body weight during the rainy season, then eats very little during the dry season. While they breed prolifically in the wild, they’re difficult to breed in captivity. As pets, savannah monitors are terrific for intermediate-level reptile keepers. However, they quickly become obese if keepers aren’t vigilant because they don’t stop eating when they’re full.

Incredible Savannah Monitor Facts

• They are often confused with white-throat monitors, but Savannah monitors aren’t as big.
• Captive-bred savannah monitors are rare because they do not reproduce well in captivity.
• This species will eat themselves to obesity.

Scientific Name and Classification

Savannah monitors are members of the Varanus genus in the Varanidae family. There are several extinct genera in the family, but the Varanus genus is the only one that contains living species. The generic name’s origin is an Arabic word that means lizard beast. Their specific name, exanthematicus, is Greek and translates to eruption or blister of the skin – it refers to the large oval scales on the back of the monitor’s neck that resemble blisters.

In Europe, savannah monitors are called Bosc’s monitor, after the French scientist Louis Bosc, who first described the lizard. 

Identifying the Savannah Monitor: Appearance

Savannah monitors are medium-sized lizards from sub-Saharan Africa. Like many terrestrial monitors, this species is stout with short legs and toes. They are strong animals with powerful legs adapted for digging. Savannah monitors have strong jaws with peg-like teeth and can grow between 3.5 and 5 feet long.

People often confuse savannah monitors with white-throated monitors because they look similar. 

Savannah monitors’ color can vary according to their locale, but they are typically dark gray with lighter yellowish to tan patterns. They have large scales on their bodies, and their tails are slightly flattened with a double dorsal ridge. 

Savannah Monitor Evolution and Natural History

In Africa, where the savannah monitors roam, monitor fossils are exceedingly rare. However, most believe the fossil scarcity has more to do with habitat than lack of lizards.

Evidence shows that monitor lizards most likely evolved in Asia, over 90 million years ago. The first monitor lizards were the Telmasaurus grangeri, the Saniwides mongoliensis, and the Estesia mongoliensis in Mongolia. While they probably looked very similar to modern monitors, they seemed to have the ability to transmit venom in a similar mechanism as modern-day Gila monsters.

Unfortunately, the evidence is a bit thin because very few monitor fossils have been found. Much of our paleontological evidence comes from fragments of a skeleton – a piece of a jaw or a vertebra – so it’s difficult to discern much. Even so, a few early fossils found in Alberta, Canada, and Wyoming, U.S.A., have been tentatively identified as monitor lizards too. Most scientists agree that Asia and North America were still connected when monitor lizards first appeared.

Varanus, the genus containing all living monitor species, didn’t show up in the fossil record until around 25 million years ago. Many of these early monitor lizards were really big, and some in Australia measured over 7 meters long! However, those in Africa diversified and shrank in size to what we see now.

There are over 46 monitor lizard species worldwide. While the Varanus genus lizards all look very similar in body type, their size and color vary widely.

Savannah Monitor Behavior

These lizards are primarily terrestrial and use abandoned burrows or dig their own as shelters. Savannah monitors are diurnal and spend their days rooting around for insects and other invertebrates to eat. In the wild, they gorge themselves during the rainy season to grow fat, then live off these reserves during the dry season. This behavior is necessary in their native range, but it makes them voracious eaters inclined toward obesity in captivity.

Males are particularly territorial and try to intimidate one another by threats. If that doesn’t work, the males wrestle and often injure each other with thier sharp little teeth.

Savannah Monitor Habitat

This species lives in sub-Saharan Africa primarily north of the equator. The original specimen that Bosc described was from Senegal, but they’re also present in Mali, Eretria, Benin, Togo, Ghana and several other countries. Savannah monitors live where the surface temperatures can easily exceed 100ºF on a hot summer day. Fortunately, these monitors find habitats with enough loose soil to dig a shelter from the hot sun. This species usually lives in savannah or open grassland areas. However, they’ll also make themselves at home in woodlands, open forests, and semi-desert habitats.

Savannah Monitor Diet

Where many monitors will eat just about anything, savannah monitors are more selective. These lizards almost exclusively eat snails, slugs, millipedes, beetles, and other invertebrates. Their diet changes a little depending on what’s available in their habitat, with some eating more slugs and others consuming more crickets and katydids. However, some also eat lizard and frog eggs, scorpions, and even amphibians.

As pets, savannah monitors can quickly become obese – they are relatively sedentary and have a huge appetite.

Savannah Monitor Predators, Threats, Conservation, and Population

Several predators eat savannah monitors, including large snakes, birds of prey, and other carnivores in the region. People often hunt this lizard for food, traditional medicine, and pet trade export, adding to the stress on the species.

Savannah monitors are common in sparsely populated habitats and in protected areas. They’re particularly common near loose sandy soils and low-intensity agricultural areas. Young savannah monitors can exist in higher densities than adults, such as 357 lizards per two-thirds of a mile. There’s no information on a population trend, and historical accounts vary from common to rare, depending on the region.

In 2012, the IUCN Redlist of Threatened Species determined that the savannah monitor is a species of “least concern.” Their population appears stable as of the assessment, but more research and updating is needed to discern whether exportation and hunting has caused a decline in savannah monitors.

Savannah Monitor Reproduction, Babies, and Lifespan

According to The Savannah Monitor News, about four weeks after a female successfully mates, she digs a hole in the ground and buries 15-45 eggs that hatch after about five months. The babies stay in the nest until a few days after they absorb all of their yolk sacks, which sometimes takes more than 12 days.

This species is the most common of all monitor lizards in captivity and has a lifespan of up to 20 years. Almost half the international trade in live monitor lizards involves the savannah monitor. Unfortunately, their captive breeding is hit-or-miss with a high mortality rate. No one knows exactly why, but some suspect it’s because the habitat required for the species isn’t well-understood. Their adult size and overall commonality in the pet trade make them more common in rescues than other lizard species.

Savannah Monitors and People

Locals in Mali hunt savannah monitors for food. Their place on the human food chain aside, these intelligent animals are popular pet lizards. They’re more docile than other monitor species and relatively easily handled. However, they have specific care guidelines that keepers must follow for them to thrive in captivity.

Monitors that aren’t handled properly and with enough regularity can become defensive and prone to biting. They have small, sharp teeth and use their tails as whips.

Basic Pet Setup

Savannah monitors in captivity are excellent escape artists; their intelligence and inquisitiveness often lead them into trouble. These lizards do well in a large enclosure, of at least 8 feet long by 4 feet wide and 3 feet high, that prevents escape. However, they tend to tear up decorations, so only the toughest enrichment items should be included in their enclosure.

They need UV-B lighting on a 10-12 hour cycle and ceramic heaters at night to maintain temperature gradients for the lizards to thermoregulate.

Related Animals

• Crocodile monitor
• Ackie monitor
• Lace monitor