Thermal gradient
The range of temperatures across an enclosure, from a warm basking end to a cool end.
A thermal gradient is the hot-to-cool spread the animal moves through to thermoregulate. You create it by putting the heat and UVB at one end and leaving the other end unheated, so the animal can pick its spot.
Aim for species-correct numbers at each end (a desert basker wants a hot basking surface and a warm cool-side; a temperate species wants lower everything), and always check the cool end is genuinely cool, an enclosure that is uniformly warm gives the animal nowhere to escape the heat.
Related terms
baskr turns the fundamentals into practice, log temperature, humidity and weight and it scores each animal against species ideal ranges, flagging problems early.
Start freeMore basics in the glossary, or jump to the health reference and care guides.
General husbandry guidance, not veterinary advice. Always confirm details for your species with an up-to-date care sheet, an experienced keeper or an exotics vet.