I understand why dogs pant and humans transpire, namely for temperature homeostasis. So why don't cats need to do either, even after expending a lot of energy on a hot day?
Cats are smaller and hotter than dogs and humans, with a temperature between 100.4°F and 102.5°F (38.1°C to 39.2°C).
Smaller animals have a higher surface-to-volume ratio and so radiate excess heat more efficiently.
Being hotter, cats tolerate higher temperatures.
I could not find an accessible ref for this, please insert some if you can find some.
Transpiring and panting are ways to regulate body temperature. When sweat evaporates, it cools the skin, and panting releases heat through the mouth. Horses, humans and even plants transpire for this reason, while dogs and birds pant. But how do cats release heat?
In fact, cats sweat through their paws. It appears that a cat after it has been frightened may leave wet pawprints on the floor. Although it's all over the internet, I couldn't find a convincing picture and as a cat lover, I've never noticed this phenomenon. That aside, cat's paws have little surface area, and cannot provide much cooling power. Instead, felines have other, more effective strategies to adjust their core temperature. Like dogs, they often sprawl out on cool surfaces (Fig. 1), or they seek out the shade on hot days. They also tend to sleep a lot, which reduces core temperature and is preferable of being very active in hot times in terms of body temperature (Fig. 2).
Fig. 1. Sprawling cat. source: Columbian blogs
Fig. 2. Cats in the shade. source: Cat memes
- Indiana Public Media