Most heat-tolerant canid

The most heat-tolerant canid is the fennec fox (Vulpes zerda), native to North Africa's Sahara Desert from Morocco to Egypt, as far east as Egypt's Sinai Peninsula, where it can survive in environmental temperatures exceeding 38°C (100°F). When the environmental temperature reaches this level, the fennec dissipates excess body heat by panting at an incredible rate of up to 690 breaths per minute after chasing prey (its normal panting rate is around 23 breaths per minute), and is so acclimatized to high environmental temperatures that it begins to shiver if the external temperature falls below 20°C (68°F). Its body temperature can rise to as high as 40.9°C (105.6°F) before beginning to sweat, helping to limit water loss.

The fennec is also the world's smallest fox with a body length is no more than 40 cm (1 ft 3 in), and it has a thick bushy tail of around 20 cm (7.8 in).

Relative to body size, the fennec has the largest ears of any wild canid, accounting for 16-20% of its total body surface, which is believed to be yet another adaptation for surviving high environmental temperatures. This is because excess body heat is rapidly dissipated by evaporation via these proportionately huge ears. Having said that, it avoids the most extreme, daytime desert temperatures by remaining underground inside its burrow until night-time arrives, bringing cooler temperatures, at which point the fennec emerges to hunt.