There are lots of things we know about dogs: they're great companions, they have a good sense of smell, and they can't eat chocolate. But there are plenty of surprising and interesting things about pups that you probably don't know - particularly about their anatomy and physiology. Here are 12 cool facts about your canine companion:
1. A dog's heart beats 50 times faster than the average human heart.
2. When dogs sweat, they do so through the pads of their feet because they only have sweat glands in their paws.
3. There are over a dozen separate muscles that control a dog's ear movements.
4. A dog's nose-print is as unique as a human fingerprint.
5. Dog noses also have a thin layer of mucus that helps them absorb scent better.
6. And the longer a dog's nose is, the more effective their internal cooling system is. This is why Brachycephalic dog breeds are more prone to overheating than other dogs.
7. Dogs have the same type of rapid eye movement (REM) as humans. Look for twitching and paw movements during sleep, as those are signs that your dog is dreaming.
8. Dogs have three eyelids - an upper, a lower and a third that protects their eyes and keeps them moist.
9. Dog's eyes also have a membrane called the tapetum lucidum that allows them to see in the dark.
10. When a dog plays with other pups or humans, his or her brain releases oxytocin or "the love hormone."
11. Dogs can reach the same level of intelligence as a two-year-old. They can understand up to 250 words and phrases as well as can count to five.
12. Not all dogs can swim and it has to do with anatomy and physiology. Dogs with very short legs, disproportionately large or heavy heads, and short muzzles and flat faces (Brachycephalic) have trouble swimming. Some examples of breeds are Bulldogs, Pugs, Basset Hounds, and Dachshunds.