Why do dogs have whiskers? Why are dogs' eyesight black and white? Why do dogs have so many babies? Why do dogs have tails and we don't? Why are dogs thumbs so high on their paw? Why don't dogs sweat? Why do dogs roll in the grass? Why aren't dogs and cats friends? Veterinarian and dog scientist Jessica Hekman has answers.
"Dogs don't actually rely on eyesight as much as we do. Their noses are really, really good, and so they have these other extra good senses that help them out more than ours. Just as their noses are better than ours and they use them to explore the world more, they also have whiskers to help them feel their way around in low light.
"So if you were walking around and you couldn't see very well and you were coming close to bumping up against a wall your whiskers would warn you before you bumped up against the wall. That's why dogs and cats have whiskers. That's just another way, another sensory input system that they use that we don't really need partly because our eyes are so much better, but also partly because we aren't as interested in moving around in the twilight as they are because they're predators and that's a really good time for them to hunt."
"Actually dogs can see some colors, they don't actually just see black and white. They see fewer colors than we do. They don't actually see red, but they can see blue and green and yellow.
"Then the question I think is really why humans can see red, right? And the answer is probably that our ancestors evolved that ability so that they could see brightly colored fruit like red or orange fruit, which was probably an important part of our diet millions of years ago. If you look at other animals who can see reds, other primates who are very interested in fruit and also birds who are very interested in fruit can also see red. And again just like with the whiskers question, dogs don't rely on vision as much as we do so that could be another part of the story, that having detailed color vision is just not as important for them."
"Different kinds of animals have different litter sizes and dogs definitely do have larger litter sizes than humans.
"Some species have really, really large litter sizes and as a result they kind of don't expect many of the babies to make it all the way to adulthood. Sea turtles are a really great example of this. They can lay dozens or hundreds of eggs in one nest. But often from that one nest you only see one or two babies growing all the way up and sea turtle parents don't really stick around all that much to help out. They lay the eggs and they're out of there and the babies are on their own and so to increase the odds of a couple of them making it they have a whole bunch.
"Humans and elephants are on the opposite extreme. Both of us, our species have very few, just one or two babies at a time, but almost all of our babies get all the way to adulthood and then our parents take really good care of us. Your parents are probably going to take care of you for about 18 years, which is a very different commitment from a sea turtle laying an egg and leaving.
"Dogs are somewhere in the middle. And if you talk to a dog breeder you will find out that in a litter of puppies, it's not that uncommon for one or two to not make it. But on the whole most of them do." - Dr. Jessica Hekman, veterinarian and dog scientist.
Clarification: In the audio for this episode, Dr. Hekman misspoke about how horses walk. They walk on one toe.
Listen to the full episode for answers to all of your dog questions.