Argentine tegu: why it needs less heating during the breeding season
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
An Argentine tegu that stays warm at night, hours after the heat lamp has switched off, isn't unusual in spring: the animal is generating that heat itself. A study by Tattersall, Leite, Sanders, Cadena, Andrade, Abe and Milsom, published in 2016 in the journal Science Advances, tracked body temperature and metabolism in Argentine tegus (Salvator merianae) across the year, from winter dormancy through the breeding season (see the study). Find our other pointers in the bedding and habitat section.
Contents · 5 sections
A body temperature that outpaces the surrounding air at night
Between September and November, at the height of the breeding season, tegus' nighttime body temperature stayed above ambient air temperature, with an average rise of 4 to 5 degrees Celsius and peaks of up to 10 degrees in some individuals.
A metabolism that surges, unrelated to activity
This heat production came with a rise in resting metabolic rate, two to three times higher than during the winter period, along with a heart rate more than six times faster than during dormancy, even though the tegus stayed largely motionless at night.
What this means for terrarium heating
An adult tegu at the peak of the breeding season can therefore stay warm at night with no artificial heat source at all, which complicates reading a drop in ambient temperature as a sign of insufficient heating. Conversely, artificial heat kept too high at night during this period risks adding to this internal heat production rather than replacing it.
Practical pointers
- Sharply reduce nighttime heating in spring, the breeding period, rather than keeping winter-level heat going.
- Track actual body temperature rather than air temperature alone before assuming heating is insufficient.
- Allow a genuine winter dormancy period, which appears to set up this spring metabolic surge.
- A probe thermometer stays far more reliable than judging by touch for this kind of seasonal tracking.
This seasonal metabolic shift builds on what's already known about the species' winter feeding pattern; our article on the Argentine tegu's winter brumation and feeding covers the other side of the annual cycle.
Frequently asked questions
Does this finding apply to juvenile Argentine tegus?
The study covers breeding-age adults; nothing suggests a juvenile, not yet sexually mature, produces comparable heat.
Should all nighttime heating stop as soon as spring arrives?
No, the study shows the animal generating internal heat, not a total absence of need for ambient warmth; moderate heating still makes sense outside the peaks observed.
Does this happen in other reptiles kept as pets?
The study documents this mechanism specifically in the Argentine tegu; a comparable rise in body temperature isn't described at the same scale in most other pet reptiles.
In our shop, for this use: Ventilated clear box for feeder insects, transport and quarantine, 19 cm (€17.90) · the whole shop
This guide is part of Planète Pets’s Reptiles universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.