Argentine Black and White Tegu

Because adult tegus so reliably outgrow starter tubs, the more cost-effective long-term plan is usually to build or buy adult-sized housing (6x3x3ft minimum, 8x4ft floor space common among experienced keepers) from the start, or to budget explicitly for a second, much larger enclosure within the first two years. Many keepers convert a spare closet or build a plywood-and-melamine enclosure rather than buying commercial glass, since glass of that size is expensive, heavy, and holds heat and humidity far less efficiently than an insulated wooden or PVC build.

The digging substrate is not optional decor — at 12 or more inches deep, it's a functional part of the enclosure that lets the tegu express natural burrowing behavior and, critically, gives it somewhere to brumate later. A shallow layer of bark chips over a hard floor denies the animal both, and keepers who skip the deep substrate often see more restless pacing and glass-surfing behavior than those who provide it.

The 110-135°F basking figure is unusually hot compared to most pet lizards, and it reflects a genuinely different thermal biology: tegus are one of the few reptile species with documented facultative endothermy, meaning that during their active breeding season some individuals actively elevate their body temperature above ambient through internal metabolic heat production rather than basking alone. That biology is also part of why undersized or underpowered heating setups tend to produce more visible health problems in this species than in smaller lizards that can get by on a modest basking bulb.

Because the basking area needs to run that hot over a large floor space, keepers commonly need a more powerful fixture (or a mercury vapor bulb combining heat and UVB) positioned at a specific manufacturer-recommended distance — placing it too close scorches, too far under-delivers both heat and UVB, and an infrared temp gun rather than a stick-on dial thermometer is the only reliable way to confirm the actual basking surface temperature a tegu is exposed to.

Humidity in a tegu enclosure is maintained mostly through the substrate holding moisture rather than repeated misting of dry air, since misting alone in a large enclosure evaporates too quickly to sustain the 60-80% range — a substrate that's allowed to dry out completely is a common, quiet driver of shedding problems long before it becomes an obvious husbandry complaint.

Feeding in practice looks different at every life stage. Hatchlings and young juveniles eat frequently — several times a week — leaning more heavily on gut-loaded insects and some egg, while sub-adults and adults shift toward a lower feeding frequency (roughly twice weekly for adults) with whole prey, egg, and a meaningful share of fruit and vegetable matter. A diet weighted too heavily toward rodents relative to the animal's size and activity level is a well-documented path to obesity and fatty liver disease (hepatic lipidosis) in this species, since a rodent-heavy diet is calorie-dense relative to what a tegu burns.

Feeding also has to be adjusted around brumation rather than held constant year-round: most keepers taper meal frequency and portion size in the weeks leading into the cooling season as the tegu's own appetite naturally drops, rather than continuing to offer a full adult meal to an animal that's biologically winding down toward dormancy.

The most consistent mistake is undersizing the enclosure for where the animal will be in 18-24 months rather than where it is on day one — a tegu bought as a small, manageable hatchling is a very different animal by its second year, and 'we'll upgrade later' setups routinely lag behind actual growth.

A close second is treating the winter slowdown as automatically alarming (or automatically dismissing it) rather than learning to tell the difference — a normal brumating tegu differs from a sick one mainly by starting point (was it eating and gaining weight going in?) and by absence of respiratory signs, not by the not-eating behavior itself.

A third common gap is underpowered heating for the enclosure's actual size — a basking fixture sized for a much smaller lizard setup simply cannot deliver 110-135°F surface temperatures over the kind of floor space an adult tegu needs, and the animal ends up chronically a little too cool without an obvious single cause.

At 15-20 years, a tegu is a long commitment through an unusually large size change: a hatchling that fits in two hands becomes a 3-4.5ft, several-pound adult within its first 2-3 years of rapid growth, after which growth slows and the routine stabilizes into an annual rhythm built around an active season and a multi-month brumation.

That brumation is not a minor detail — for several months each year (timing and length vary by individual and by how the keeper manages temperature and light cycle), a healthy adult tegu may eat little or nothing, move rarely, and spend most of its time buried, and a keeper who acquires this species should plan for that seasonal pattern as a normal, expected part of ownership rather than a problem to solve.

Temperament changes more dramatically over an individual tegu's life than in most pet reptiles — the tail-whipping, hissing, defensive hatchling and the calm, food-motivated, keeper-recognizing adult can be the same animal a year or two apart, and that trajectory depends heavily on how consistently it was handled early on rather than being purely a fixed trait.

Because of their strength and claws, a defensive juvenile can do real (if minor) damage during the early phase, which is why short sessions, gloves if needed, and full-body support rather than restraint are the standard early approach — rushing handling or over-restraining tends to prolong defensiveness rather than shorten it.

Individual variation persists into adulthood: most well-socialized adult tegus are described by their keepers as calm and interactive, but some remain more reserved, and an adult acquired secondhand with an unclear or rough handling history should be given the same patient reset period recommended for any reptile with an unknown past.