Degu: why it sometimes refuses to eat under a heat lamp
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
A degu that ignores its food when it sits under the terrarium's heat lamp is not being fussy: on its own scale, it is applying a documented trade-off between food quality and the thermal cost of foraging. Our feeding guidance is gathered in the rodent food section.
Contents · 4 sections
A food choice that depends on ground temperature
Torres-Contreras and Bozinovic published a 1997 study in Ecology on food selection in the degu, Octodon degus, a diurnal herbivorous rodent from central Chile (see the study). In an experimental arena, with synthetic diets of varying fibre content placed under controlled heat spots, the animals clearly favoured the lowest-fibre foods when given a choice. But when reaching the food meant exposure to a thermal load — a heat spot simulating sun exposure — degus cut back on time spent feeding at that specific spot, a behaviour documented by the same authors in related work on the species' time-energy budget.
Eating out in the open has a cost the animal weighs up
This result fits the degu's own biology: limited heat tolerance and limited evaporative water loss make prolonged exposure at a heat spot thermoregulatorily costly. The animal is therefore not choosing based on nutritional value alone, but also on the physiological price of reaching and eating the food. In the wild, the authors note that degus sometimes end up eating far more fibre-rich plants during the dry season — not by preference, but because low-fibre food is simply no longer available: necessity overrides choice at that point.
The study was carried out in an experimental arena with synthetic diets, a more controlled setting than a home terrarium. It does not precisely quantify, for a pet animal, the distance or exposure time at which avoidance kicks in: it establishes the trade-off in principle, not a fixed threshold to transpose directly.
What this changes in the setup
- Never place the main food bowl directly under the heat source: a degu may reduce its intake rather than expose itself, even with food available there.
- Provide a temperate feeding zone away from the heat spot, in addition to a warm zone for resting or active thermoregulation.
- Favour good-quality, lower-coarse-fibre hay as the staple food, matching the species' documented preference when a choice is possible.
- Watch a degu that eats little during hot weather: avoiding the heat spot can compound with a general reluctance to move toward food in the heat.
Frequently asked questions
My degu eats less in summer, is that a concern?
A drop linked to ambient heat is not inconsistent with this study, but any weight loss or prolonged refusal to eat should always be checked by an exotic-animal vet rather than assumed to be about temperature.
Should I remove any heat spot from the terrarium?
No: the heat spot still serves thermoregulation. The key is not to stack the main feeding spot on top of it. See our guide on degu diet and diabetes risk.
Does this same trade-off apply to chinchillas?
This specific study covers the degu. Find our degu care sheet and all our guides on the rodent hub.
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This guide is part of Planète Pets’s Rodents universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.