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Your Pet Explained: The Truth About Cats and Dogs

Shaina Fishman Photography

If men are from Mars and women are from Venus, then cats and dogs must come from Jupiter. How else to explain some of their, well, alien behaviors? Just what, exactly, is a dog thinking when he rolls around in something stinky? If a cat naps on a computer keyboard, is it because she’s expecting an email? We went to the experts (the human kind!) for answers.

My dog seems to run in his sleep. Could he be dreaming?
Perhaps. “We can’t ­really ask them,” says veterinarian Melissa Bain, associate professor at the UC Davis School of Veterinary Medicine, “but we think they dream.” That’s because their brain-wave patterns resemble those seen in people. “Dogs go through sleep cycles very similar to humans’, with periods of deep sleep and periods of rapid eye movement, or REM, sleep,” says Stephen Zawistowski, Ph.D., an applied animal behaviorist and science adviser to the American Society for the Prevention of ­Cruelty to Animals. “Dreaming happens during REM sleep, which is also when dogs twitch their legs, move their lips, or vocalize.” ­Wonder when your own dog might be dreaming? As a dog starts to doze, and his sleep becomes ­deeper, his breathing will become more regular, says canine ­behavior ­expert Stanley Coren in his book How Dogs Think. “After a period of about 20 minutes,” Coren writes, “his first dream should start.”

Why can a cat always land on its feet?
“Cats have a very flexible spine that allows them to twist in the air and right themselves as they fall,” says ­Zawistowski. “But cats can injure themselves quite severely if they fall from high places. Every year, vets treat [many] cats that fall from windows in upper floors of apartment buildings. This is so common that it has a name, ‘high rise syndrome,’ due to the consistent nature of the injuries.”

Why do dogs like to have their bellies scratched?
“Not all dogs like it, but for those that do, it’s a way of bonding,” says Sophia Yin, a veterinarian and applied animal behaviorist in Davis, Calif. Besides which, Zawistowski says, “Dogs have a difficult time scratching some areas of their own bellies. Because they’re sensitive there, the greater agility of human fingers is probably more pleasant than their own toenails.” But remember, Bain says, when a dog rolls over, “that can also be a sign of fear.” If you approach a dog that is uncomfortable or afraid, keep in mind that it could respond by showing aggression.

Do dogs and cats have a sense of humor?
According to the experts we spoke to, studies have not yet been done to assess pets’ sense of humor. But if we’re talking about a sense of fun, then the answer is yes. We humans so prize fun in dogs, we’ve ranked the breeds on a playfulness scale. Among those at the top: Irish setters, English springer spaniels, ­Airedales, miniature schnauzers, and poodles. As for cats, says ­Jackson Galaxy, host of Animal Planet’s My Cat From Hell,“The fact that cats live willingly with us is proof positive they have a sense of humor!”

My dog likes to lie in mud puddles and other icky places. Why?
Mud puddles? That’s easy: In hot months, they’re like an instant air conditioner for your furry pooch. As for smelly places, Zawistowski says “nice” is in the nose of the beholder. “While rotting fish may not smell great to you, to your dog—descended from critters that scavenged for meals—it probably smells as good as fresh-baked chocolate chip cookies. Rolling in it is just a way to enjoy it all the more.”

Can a cat be trained the way a dog can?
Cats are not as inherently interested in pleasing humans as dogs are, “but they can be trained if there’s something in it for them,” says cat behaviorist Mieshelle Nagelschneider, author of the book The Cat Whisperer. “I’ve trained my cats to give me high fives.” Some cat owners use clicker training; learn more at

One of my cats loves catnip; the other couldn’t care less. What gives?
Catnip, a member of the mint family, contains a substance called nepetalactone that stimulates some, but not all, cats. “About one-third to one-half of all cats are sensitive to it,” says Zawistowski. “They’ll respond by rolling in it and acting intoxicated.” Unfortunately for Kitty, the catnip high lasts only about 15 minutes.

Why does my dog like to smell other dogs' behinds?
Pheromones produced in glands in dogs’ cabooses provide info “about their sex, reproductive, and social status,” says Zawistowski. And there’s another reason: “By sniffing the back,” Bain says, “they avoid approaching a dog head-on, an action that can signal a challenge.”

RF Pictures/Corbis

Why does my cat like to sleep in weird places, like atop keyboards or inside cardboard boxes?
Simply put, it’s what their ancestors did. “In the wild, cats like to take refuge in enclosed spaces and also like to claim locations because of their territorial nature,” says Nagelschneider. “And what cat can pass up a warm keyboard? It’s made particularly special because a human is touching it all the time.”

I have a “knead-y” cat. What’s she up to?
“This remnant behavior from kittenhood reminds cats of nursing on their mother,” says Nagelschneider. Domesticated adult cats do it for attention—a good thing, adds Yin: “It’s something cats do when they are contented.”

Why do cats like to nap so much?
Cats typically sleep 12 to 16 hours a day, and because they’re crepuscular, meaning they hunt at dawn or dusk, they can be more active at night. But house cats don’t necessarily need—or want—to sleep as much as they do, says Yin. “How much a cat sleeps has a lot to do with how stimulating its environment is.” To cure Bored Cat Syndrome—the real name for this forced kitty ennui—provide your cat with toys, tiered cat trees, and cat tunnels when you’re gone, and bubbles, lasers, and fishing pole–type “prey toys” when you’re home and can play with her.

Can dogs and cats get colds from us?
Dogs and cats can get colds, with the same miserable symptoms (sneezing, coughing, ­watery eyes) we get, but they don’t catch them from us. Most viruses are unique to a species; whereas our common cold is caused primarily by the rhinovirus, most dog colds come from Bordetella bacteria or canine flu viruses, and most cat colds are due to feline herpes, caliciviruses, or Bordetella bacteria. Nonetheless, recently researchers have expressed concern about “reverse zoonosis,” in which humans pass diseases to ­animals through mutations and new viral forms. So if you are under the weather, rather than snuggling up with Fluffy, keep your distance—for her safety.

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My cat always seems to gravitate toward people who either don’t like cats or are allergic. Am I imagining this?
Probably not. As with most cat behaviors, it all boils down to survival, says cat Nagelschneider. “Cats like to play it safe and approach people who are not overtly trying to draw their attention with expressions, vocalizations, and other gestures. With someone they don’t know, those gestures can feel like too much pressure and even be perceived as threatening. People who are averse to cats are often passive, and to cats, this can feel safer.”

Why does my cat like to drink out of water glasses and sinks?
“In nature, cats will avoid drinking water that is next to dead prey because the water may be contaminated with bacteria,” says Nagelschneider. “Inside the home, this instinct also applies—they want to drink water that is located far away from their store-bought food to ensure healthy water. We always tell cat owners to be sure to locate the water bowl in its own designated ‘watering hole’ area.”

Why don’t cats like sweets the way dogs do?
“Cats are carnivores; they need to eat meat and they don’t digest carbohydrates as well,” says Dr. Yin. “They are also more discriminating about food than dogs, and more susceptible to toxins than dogs. Dogs, in contrast, evolved as scavengers, living off human dump sites, and the ones that did the best at that survived. They are better adapted to eating the things we do.” And that rapture we feel over chocolate? There’s another good reason why cats instead say “Meh,” not “Meow.” Says Zawistowski: “At some point during the evolution of cats, a mutation in their sensory system caused them to lose the capacity to taste sweet.”

What is my cat trying to tell me when he rubs up against my leg?
Cats have scent glands on both their cheeks and the base of their tails, and they are leaving their scent marks. “Rubbing against humans and other cats can help maintain the very important group scent that serves as a social glue,” says Nagelschneider. “Cats feel affiliated and relaxed with those that carry the group scent.  People have the same last name in families, but cats have scent last names. Rubbing can be proprietary in nature as well, and the cat may be claiming you if he or she rubs on you. This also goes for leaving their scent and pheromones on objects they want to claim to let other cats know they’ve been there. For example, a cat may mark a couch if they can’t mark you because you’re busy putting the groceries away.”

Why do cats automatically know to pee in litter boxes?
Cats instinctually dig and bury their urine and feces, but not just for our convenience. Because a cat’s urine has a strong odor that can potentially be smelled by predators, wild cats learned to urinate away from where they slept and ate, and to cover their urine. That instinct is still strong today in domestic cats. Unfortunately, not using litter boxes (often a sign of some other behavioral problem, like stress or anxiety) is the No. 1 complaint of cat owners and the No. 1 reason millions of cats are surrendered to shelters each year. “I’ve heard of owners finding unwelcome gifts from their cats inside shoes and coffee mugs,” says Nagelshneider. “I once solved the curious case of a smelly toaster,” she says in her book The Cat Whisperer.

I’m tempted to get a DNA test to find out what breed(s) my mutt is; how do those tests work?
The canine DNA tests, which cost $60 and up, involve swabbing the inside of your dog’s cheek and sending in the sample to the research company; results come back in a few weeks. Their accuracy depends on a number of factors; if a mutt has many breeds in its background, the results will typically be less reliable than a mutt with a purebred parent or grandparent. “All dogs are descended from a wolf ancestor,” says Zawistowski. “Over time, genetic mutations gave rise to the various breeds we have today, each of which has accumulated different changes in their DNA. The tests are based on an analysis of these differences and are most reliable when the breeds are easily distinguished. It’s more difficult to differentiate between breeds that are closely related, or when one breed has been derived from another.”

Have more questions about your pet? Join us for a Google Hangout with Cesar Millan and Jackson Galaxy on Friday, July 25, at 1:30 p.m. ET. RSVP here.

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