Black Throated Monitor

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The black throated monitor is a big, thickset lizard from the savannas of East Africa. It belongs to the same species as the white throated monitor, Varanus albigularis. The two are best understood as one animal with two common names, not two separate lizards.

Keepers use “black throated monitor” for animals from the eastern part of the range, formally the subspecies Varanus albigularis microstictus. Older trade catalogs called these lizards Varanus albigularis ionidesi. That name is now treated as a synonym of microstictus.

This page covers the whole species. Keepers searching for a black throated monitor, a black throat monitor, or a black monitor lizard are almost always asking about one thing. It sits within the wider monitor lizard family, alongside relatives like the Nile monitor and the savannah monitor.

Care Overview

Care for this species starts with accepting the size of the commitment. This is not a lizard for a small tank on a desk.

An adult needs floor space measured in feet, not inches. It needs a heavy duty enclosure it cannot force open, deep digging substrate, and a calm, confident keeper.

Diet, heat, and UVB all matter. But two things go wrong most often: undersized housing and underestimating how food driven an adult becomes.

Good husbandry also means planning years ahead. A hatchling the size of a pencil grows into one of the larger lizards most keepers will ever own.

Our guide to choosing a pet lizard is worth reading first. It can help you decide whether this species fits your household.

Housing

Hatchlings and small juveniles can start in a secure glass or PVC enclosure around 4 feet by 2 feet. They outgrow that space quickly, eventually needing something like the New Age Pet ECOFLEX Mojave Reptile Enclosure.

Adults need something on the order of 8 feet long, 4 feet wide, and 4 feet tall, or larger. Many experienced keepers eventually convert an entire room once the lizard reaches full size.

Custom built wood, PVC, or concrete block enclosures are common in adult setups. Standard glass terrariums rarely hold up to a monitor this powerful for long.

Substrate should be deep enough for real digging. This species excavates burrows in the wild, and it stays calmer with the same option in captivity.

A mix of topsoil, play sand, and coco fiber works well. Kept slightly damp at the bottom, it lets an adult dig tunnels several feet long.

Sturdy hides at both the warm and cool ends give the lizard a place to retreat. Thick branches or a basking platform let it climb, since this monitor uses elevated perches as well as burrows.

For general build ideas and material choices, see our guide to lizard enclosures.

Heating and Lighting

Like other large African monitors, this species needs a strong thermal gradient and intense UVB. That is a bigger setup than many smaller lizards require.

Keepers commonly aim for a focused basking surface well into the low 100s Fahrenheit. The ambient warm side often sits in the 90s. The cool side drops into the 80s, with a modest nighttime dip.

These are large, active, sun loving lizards. Many setups use multiple basking bulbs, such as the Arcadia Halogen Basking Lamp, or a mercury vapor bulb, to cover a big basking platform instead of one small hot spot.

UVB output should be high. Strong tube or mercury vapor fixtures work best. Position them so the lizard can bask close to the bulb without risking a burn.

Bulbs should be replaced on the schedule the manufacturer recommends, even if they still glow. Exact temperature and UVB numbers vary between keepers and sources, so treat any figure as a starting point.

A reptile veterinarian or an experienced monitor keeper can help fine tune a first setup. A large, heavy water basin supports drinking, and soaking gives the humidity spikes this species benefits from.

What This Species Eats

In the wild, this monitor is an opportunistic hunter. It eats invertebrates such as snails, millipedes, and beetles, plus vertebrate prey like rodents, birds, eggs, and other reptiles.

Captive diet plans usually mirror that variety. Keepers offer appropriately sized whole prey rodents, day old chicks, and gut loaded insects such as roaches and crickets.

Whole prey items matter because they supply calcium and other nutrients in roughly the right balance. That lowers the risk of metabolic bone disease compared with a diet built mainly around muscle meat.

Hatchlings and juveniles eat more often, several times a week. Adults typically eat less, since this species can put on excess weight if fed like a much smaller lizard.

Obesity is a real and common problem in captive monitors. Feeding schedules should track the individual animal’s body condition rather than a fixed calendar.

Fresh water should always be available, since this species drinks and soaks regularly. Our broader guide to what lizards eat covers how these principles apply across other large lizard species too.

Health and Common Problems

Metabolic bone disease is one of the most common problems in captive monitors. It comes from poor calcium to phosphorus balance and inadequate UVB. It shows up as soft jaws, swollen limbs, or reluctance to move.

Obesity is just as common in adults that are overfed for their activity level. It shortens a lizard’s healthy years, even though it is easy to miss day to day.

Internal and external parasites are worth screening for too. A fecal exam from a reptile veterinarian is the reliable way to check, especially for an animal with an unclear source history.

Thermal burns from bulbs or heat mats that sit too close are common too. So are mouth infections from rough substrate or sharp enclosure decor.

A lizard that stops eating, breathes with its mouth open, or drags a limb needs a reptile veterinarian. Swelling is a warning sign too, and none of these should be treated at home from guesswork.

Our lizard health guide walks through warning signs shared across large monitor species.

Behavior and Temperament

These lizards are alert, intelligent, and highly food motivated. That food drive is the trait keepers mention most often.

The intelligence is documented, not just keeper lore. In a study published in Animal Cognition, eight juvenile black throated monitors learned to open a hinged food tube within ten minutes on their first try, and got faster on repeat trials.

An animal that is calm during routine handling can still lunge hard at the first sign of food. Consistent handling routines and clear cues before feeding matter more with this species than with many other pet lizards.

Wild caught or poorly socialized individuals can be genuinely defensive. They may hiss, inflate the body, whip the tail, and bite if they feel cornered.

Captive bred animals raised with regular, calm handling are generally more manageable. Even so, this is a large, strong animal with a powerful bite and sharp claws.

Every adult deserves careful, confident handling rather than casual treatment. Most individuals settle into a routine once they trust a keeper, and they grow more predictable with age.

Breeding

Breeding large monitors like this one is a project for experienced keepers. It takes space and resources for multiple large enclosures, not a casual setup.

This species is oviparous, laying eggs rather than giving live birth. Clutch sizes and incubation details are documented far less consistently than for more commonly bred pet lizards.

Successful captive breeding is uncommon relative to demand in the pet trade. That is one reason animals on the market are frequently wild caught or hatched from imported eggs. The IUCN Red List assesses the species as Least Concern across its wide African range.

Anyone considering breeding should research current, species specific protocols in depth. Expect a steep learning curve rather than assuming general lizard breeding knowledge will transfer directly.

Lifespan and Size

This subspecies is among the largest lizards commonly available in the US pet trade. Adults commonly reach roughly 4 to 5 feet in total length.

Some keepers and dealers report exceptionally large individuals well past that. Reports vary and are not well documented, so treat the biggest size claims as an upper edge, not the norm.

Females and males can differ in bulk and proportions as they mature. Body condition also varies enormously with diet, so weight is a less reliable size indicator than length.

For comparison, the Asian water monitor reaches an even larger typical size. The savannah monitor stays noticeably smaller.

With attentive care, monitor lizards this size are commonly reported to live 10 to 15 years in captivity. Some live longer under excellent conditions. Lifespan data specific to this subspecies is limited.

Cost of Ownership

The purchase price for a young animal is often modest. This species is not rare in the trade, so hatchling prices stay reasonable.

The real expense comes from building and running adult sized housing. Budget for a custom enclosure, high output UVB and heating fixtures, and the electricity to run them for years.

Food costs add up too. A growing juvenile eats often, and an adult still needs a steady supply of whole prey rodents and other feeders.

Veterinary care from an exotics or reptile focused vet is an ongoing cost. First time buyers frequently underestimate checkups and treatment for the health problems described above.

Anyone budgeting for one of these lizards should plan for the adult enclosure first. Cover its running costs before bringing home a hatchling, not after it has outgrown its first tank.

Frequently Asked Questions

How big does a full grown black throat monitor get?

Most adults reach roughly 4 to 5 feet in total length. Some individuals are reported larger, but sources and keepers disagree on how common that really is.

Is a black throated monitor the same as a white throated monitor?

Yes, both names refer to the same species, Varanus albigularis. Black throated describes the East African subspecies, microstictus. White throated usually refers to the more southern nominate subspecies.

Are black throated monitors good pets for beginners?

Generally no. Their adult size, strength, and food driven temperament fit a keeper who already has experience with large reptiles better.

What do black throated monitors eat in captivity?

A varied diet works best: appropriately sized whole prey rodents, day old chicks, and gut loaded insects. Fresh water should always be available, and whole prey supplies calcium in a healthier balance than muscle meat alone.

How much does a black throat monitor cost to keep?

The animal itself is usually inexpensive. A suitable adult enclosure, strong UVB and heating fixtures, feeder costs, and veterinary care add up over the lizard’s lifespan.

Do black throated monitors have recognized color morphs?

No widely recognized morphs exist for this subspecies the way they do for some popular pet lizards. Natural variation in pattern and darkness happens between individuals and populations instead.