Monitors and Tegus: When a Lizard Outgrows the Room

Monitor lizards and tegus are intelligent and impressive, but they grow big and strong. Savannah monitors and Argentine black and white tegus commonly reach about 3–4.5 feet (90–140 cm), tegus nearly 5 feet (150 cm), and live up to about 20 years. An adult needs an enclosure about the size of a small room, deep soil to dig, intense heat and UVB, and a confident, experienced keeper. They are not starter lizards.

An adult Argentine black and white tegu in a large, room-sized enclosure — A tegu needs room-sized space, deep soil to dig and a hot basking spot.

The Size Gap

Baby savannah monitors and tegus are sold at a few inches long. Within two or three years they are 3–4 feet (90–120 cm) of muscle, claws and tail. Experienced keepers commonly house a single adult in an enclosure of at least 8 × 4 × 4 feet (240 × 120 × 120 cm), and many give a whole room. Bigger monitor species need far more.

Strength and Handling

An adult tegu or monitor can scratch, tail-whip and bite hard enough to need medical care. Many tegus become calm with consistent handling; many monitors stay wary. Either way, handling an animal this size takes confidence, experience and respect, and it isn't for children.

Not the Same Category as a Bearded Dragon

Heat: very hot basking spots and a wide temperature gradient across a big space.
UVB: strong UVB over a large area.
Digging: deep, moist soil for burrows, which means a strong, deep enclosure base.
Food: whole prey and other animal foods (and fruit for tegus), in quantity, with a lot of cleaning afterward.
Time: daily care for up to about 20 years.

The Law

Rules differ by country and state. In the US, Florida has banned new pet tegus and requires a permit for tegus kept before the ban, because escaped tegus are now an invasive species there; other states have their own rules. Some large monitor species are licensed under dangerous wild animal laws in some countries. Check with your national or state wildlife authority before you buy.

The Experienced-Keeper Path

If you are determined, gain experience with smaller lizards first, visit experienced keepers to see adults in person, plan and build the full adult enclosure before you buy, and line up a vet who treats large lizards. Consider adopting from a reptile rescue, where many outgrown monitors and tegus end up.

Frequently Asked Questions

Size and handling come up most.

How big do tegus get?

Argentine black and white tegus can reach nearly 5 feet (150 cm), with males the larger.

How big an enclosure does an adult monitor or tegu need?

Experienced keepers commonly use at least 8 × 4 × 4 feet (240 × 120 × 120 cm) for one adult, and many give a whole room.

Are tegus good for beginners?

No. Some become calm and handleable, but their size, strength and care needs suit experienced keepers.

Are tegus legal?

It depends where you live. Florida has banned new pet tegus because they've become invasive there. Check with your national or state wildlife authority.

What's a good alternative to a monitor or tegu?

A blue-tongued skink: calm, sturdy and characterful, at a fraction of the size.