Black Throat Monitor

“The black-throat monitor is the second-longest lizard species in Africa and the largest in mass.“

Black Throat Monitor Facts

• The black-throat monitor is the heaviest in mass and second-longest lizard species in Africa in terms of length. They grow up to 7 feet in length and weigh over 60 pounds!
• They are excellent climbers. They live in trees for most of their juvenile life.
• Pet black-throat monitors are known to be very affectionate toward their owners. They even follow them around the house.
• Black-throat monitors can break their own thyroid bone while attempting to fit whole prey in their mouths.
• These lizards enjoy being taken out on leashed walks. Just don’t let them loose because they will likely climb up a tree and refuse to come back down.

Black Throat Monitor Summary

When it comes to mass, the black-throat monitors are the largest lizard species in Africa, and the second longest in length, second only to the Nile monitor. Their name comes from the patch of dark scales on their throat which differentiates them from the white-throat monitors. Unlike other monitor species, the black-throat isn’t a great swimmer. However, it makes up for it by being a fantastic climber.

Black Throat Monitor Scientific Name

The binomial classification of the black-throat monitor is Varanus albigularis, which is a group of rock monitors. It belongs to the genus Varanus, which is derived from the Arabic word waral meaning “warning.” The specific name, albigularis is a compound of two Latin words: albus which means “white” and gula which means “throat.” This species is called “black-throat” because of the dark scales that cover its throat.

The black-throat monitor is one of three subspecies of rock monitor lizards in Varanus albigularis. The other two subspecies are:

• The white-throat monitor (Varanus albigularis albigularis) which is the nominate species
• The Angolan white-throat monitor (Varanus albigularis angolensis)

The trinomial name of the black-throat monitor is Varanus albigularis microstictus. Although some taxonomists purport there to be four subspecies, with Varanus albigularis ionidesi being the fourth, other professionals believe there to be only three subspecies of rock monitors, with V. a. ionidesi being a description of the juvenile form of Varanus albigularis. V. a. microstictus is sometimes used interchangeably with Varanus albigularis ionidesi to classify the black-throat monitor.

These lizards are also called black-throated monitors. Both of these variations are acceptable and commonly used.

Varanus is the only genus of the family Varanidae that contains living species. Other monitor lizards that belong to this family are the komodo dragon, the Nile monitor, the Asian water monitor, and the ackie monitor.

Black Throat Monitor Appearance

Black-throat monitors are the second longest and largest monitor lizards in Africa. They are the largest of the four subspecies of rock monitors. Adult monitors grow to reach lengths of up to 7 feet in length and weigh over 60 pounds. The males are typically larger than the females. They are immense in size and, for this reason, are unpopular among the lizard-keeping community. To house them would require a great deal of space.

They are typically dark grayish-brown or tan and have yellowish or white markings to match the general color of their habitat. The mottled patterns of the markings and their color are different for each lizard. Sometimes, the markings fade as the lizard grows older, but they still remain visible. The markings are bigger on the back of the lizard and smaller around the leg and side regions of the body. Towards the tail, the markings form bands.

Black-throat monitors have an incredible defense system: serrated teeth, sharp claws, and long, powerful tails that they use as whips to protect themselves. They have short legs and a forked tongue and use it like a snake – flicking it to assess the scents around them.

Behavior

They are great climbers. What they don’t accomplish with swimming is made up for by their ability to scale trees. Juvenile monitors spend most of their life in trees to stay safe. Since they are smaller in size when growing up, they are targets for predators on the ground. They live mostly in trees until they reach their full size in adulthood and can walk freely and securely on the ground. However, when they are threatened, they may still flee to the trees.

This type of monitor can be aggressive in the wild. When aggravated, these lizards hiss, puff up their bodies, lash out with their tails, claw, and bite with their painfully sharp teeth and powerful jaws.

Black-throat monitors are burrowing animals. In their natural habitat, they like to burrow underground and hide under rocks. In captivity, there should be enough space for them to dig underground and enough boulders and rocks for them to crawl under. These monitors are diurnal animals, which means they are active during the day, usually stalking their terrain to find food, and settling down to rest at night.

Captivity

When raised around people, they become docile. They are known to be a playful and active. They like to engage in regular activities like climbing and burrowing and are intelligent enough to recognize their owners and even follow them around. Although black-throat monitors can make loving pets, it is not advisable for beginner owners. They have needs and requirements that can only be handled by expert lizard keepers.

Even in captivity, these monitors need to associate with humans regularly or else they would grow aggressive toward people. An aggressive black-throat monitor should never be approached because its bite can inflict serious damage.

Monitors should not be kept with other pets. They are too large and do not usually get along with smaller animals. In fact, they might try to eat them. These reptiles live better alone.

Black Throat Monitor Habitat and Population

The black-throat monitor is native to Tanzania. It is predominantly found in the arid regions of east African countries such as Tanzania, Somalia, Burundi, Ethiopia, and Kenya. Its range does not pass the jungles of the Democratic Republic of the Congo and South Sudan.

They exist naturally in various habitats. They like to live in hot, arid regions such as savannas, prairies, and steppes. You won’t find these monitors in rainforests or true desert regions.

An excellent climber, they live in trees during their youth in order to remain safe from predators on the ground. Like all rock monitors, adult black-throats live in burrowed holes, typically beneath trees.

If you are looking to spot these big lizards in the water, you might be severely disappointed. One difference between this monitor and other monitor lizards such as the Asian water monitor is that they are not swimmers.

This subspecies is not currently listed on the IUCN Red List of Threatened Species. However, its nominate species, Varanus albigularis, is listed as Least Concern.

Reproduction and Lifespan

The reproductive process of the black-throat monitor starts at the beginning of the dry season. First, the male and female monitors usually dwell together to mate intermittently for days. The female requires plenty of food during the breeding season in order to lay her eggs. She lays the eggs in a pre-dug hole, often at the end of a termite nest, or in damp soil. This is done in order to make sure that the eggs stay at the correct temperature and humidity level.

The clutch size varies but they are known to be able to lay more than 30 eggs at once. The eggs hatch after 116-180 days during the rainy season, ensuring that the hatchlings have a survival advantage. The rainy season comes with bountiful food and water, optimal for newborn monitors.

Hatchlings grow rapidly and reach sexual maturity within two years. They reach adulthood at 6 feet in length and at least 60 pounds in weight.

Monitors in captivity live long lives when properly cared for. In fact, they have a lifespan of up to 25 years.

Diet

They are obligate carnivores, which means they do not digest plant material and get most or all of their nutrients from flesh. In the wild, adults prey on whole animals such as rodents, other reptiles, birds, and even insects. They are an opportunistic species so they will eat almost anything they can find. They eat carrion, or dead flesh, as well as hunt their own prey.

In captivity, they still require a robust range of prey animals. Black-throat monitors are typically fed lizards, snakes, large roaches, insects, chicks, crustaceans, and fish. Insects added to their diet should be brushed with calcium supplement powder because insects generally lack in this mineral. Mice are also one of the more popular whole-prey foods for these monitors.

They will readily eat cat and dog food, but owners should not make these a go-to dietary option as they do not contain the necessary nutrients required to sustain them. Also, canned and processed food have a high-calorie content which can cause obesity. A lot of effort goes into the feeding and upkeep of these large monitor lizards, so potential owners need to consider all of this before adopting one.

These creatures have slow metabolisms and do not need to be fed daily. Instead, they should be fed a few times a week. The frequency should depend on whether the lizard is slim or overweight, so it is strongly advised to keep a watchful eye on the size of your pet.

Cooked eggs with the shells are a great source of calcium for them, but they should be reserved as occasional treats because of their high cholesterol and fat levels.

Predators and Threats

Adults are very large and formidable animals, so it comes as no surprise that they do not have many natural enemies in the wild. However, they are prey to crocodiles, pythons, eagles, and leopards. Some humans also hunt these monitors for food.

Although black-throat monitors in captivity don’t usually have to worry about predators, that doesn’t mean they cannot suffer from other health-related threats. Pet monitor lizards are prone to metabolic bone disease (MBD), which is caused by an inadequate calcium intake. Lack of calcium to fortify the bones of the lizard causes the bones to become weak and fragile, leading to movement restriction and, eventually, death. Insects are a main source of food for these monitors, but they do not contain the proper amount of calcium for them. This is why brushing the insects with powdered calcium supplement before feeding them to monitors is strongly advised.

Another serious health issue that these reptiles in captivity can face is obesity. This comes as a result of excess feeding, and also from providing too much fatty foods such as eggs and rodents. They have very slow metabolisms, so do not need to be fed daily.

Related Animals

• Asian Water Monitor
• Ackie Monitor
• Crocodile Monitor

1. Wikipedia, Available here: https://en.wikipedia.org/wiki/Black-throated_monitor
2. Biocyclopedia, Available here: https://biocyclopedia.com/index/monitor_lizards/varanus_albigularis.php
3. (1970)
4. (1970)