PH
Dogs don't regulate body temperature through sweating across their entire bodies in the same way humans do.
Their main cooling mechanism is panting, but sweat glands are present in their paw pads.
These glands can produce moisture on the feet, although paw sweating plays a much smaller role in cooling than panting.
The pads also provide cushioning and traction while walking.
Wet paw prints on a floor can therefore sometimes contain more than just water picked up from the ground. A dog's feet are doing several jobs at once.
© Merck Veterinary Manual