WHY DO CATS KNEAD? WHY DO DOGS LICK YOU? THE SCIENCE OF PETS’ QUIRKS

Bella the beagle loves boxes from Amazon. She tears into them, while ignoring other deliveries. (Amazon founder Jeff Bezos owns The Washington Post but has never met Bella.)

Little Bit, a recently departed tortoiseshell cat, was similarly obsessed — but with socks. She would raid the laundry basket in the middle of the night and paw through the open suitcases of houseguests, who invariably found themselves one sock short in the morning.

Pets do quirky things. At least it may seem that way to their humans. But these traits often make perfect sense to the pets, say scientists who study animal behavior. Such conduct often is a modern incarnation of their evolutionary roots, and also draws upon their current bond with humans.

“These behaviors are not invented on the spot,” says Carlo Siracusa, associate professor of clinical behavior medicine at the University of Pennsylvania School of Veterinary Medicine. “They are an evolution of the behavior of their ancestors that have been adapted to their new lives as domesticated animals now that they are living with humans.”

Still, dogs also can learn from humans, much as children learn from adults — in fact, many times, they learn even better than children. “If you show children how to do something and give them unnecessary steps, children will copy them,” says Angie Johnston, director of the Canine Cognition Center and Social Learning Laboratory at Boston College. “But once dogs figure out how to do it, they stop the unnecessary steps. Dogs figure out faster than children what the endgame is.”

Even so, their ancient instincts persist. Dogs, for example, often “make their beds” — as humans describe it — by scrabbling on blankets, sheets or doggy beds, then turning a few times before settling down, a habit that probably comes from an age-old instinct to create a safe, warm place to sleep.

“Think about where animals sleep in nature,” says Evan MacLean, director of the Arizona Canine Cognition Center at the University of Arizona. “They mat down an area before they lay in it.”

They also sometimes circle before they poop, which some researchers attribute to an attempt to align with the Earth’s magnetic field, specifically the north-south axis. Not every scientist is convinced. “It’s still unclear what is going on here,” says Sarah-Elizabeth Byosiere, director of the Thinking Dog Center at CUNY Hunter College. “A lot more work needs to be done.”

Sometimes dogs will paw the ground after pooping. (Advice: Wait a few seconds before bending down to pick up their waste to avoid being hit by flying debris.) They are not burying their feces.

“They are depositing scent in those areas,” MacLean says, which may explain their pickiness about a pooping spot. “They’re looking for the best part of town to put up a billboard. They want a good place to advertise. Scratching creates a ground disturbance, to catch attention. It’s almost like drawing a picture with a big red marker around it.”

The signpost is meant for other dogs, another quirk they inherited from wolves, he says. “Territory marking is very likely one function of this communication, but there is a lot of other information that might be encoded in odors that we don’t understand well as humans,” he says. “For example, animals may be able to judge things like reproductive or health status of other individuals based on odor signatures.”

Cats, on the other hand, almost always bury their waste. “They are covering their tracks,” says Monique Udell, director of the Oregon State University Human-Animal Interaction Lab. “This could be the modern-day version of keeping a low profile.”

Why your cat kneads you

Mikel Delgado, founder of Feline Minds, a Sacramento cat behavior consulting service, says that some of these traits derive from cats’ wild origins.

“Cats are highly predatory, they are naturally active at dawn and dusk, they are in the middle of the food chain — both hunters and hunted — with some behaviors that are natural, like scratching, and we can’t train that out of them,” she says.

Experts also insist that the reputation of cats as socially aloof is undeserved. They have facial scent glands, and when head-butting their human, they are probably depositing secretions to mark their social partners, says Kristyn Vitale, assistant professor of animal health and behavior at Unity College.

“Kneading” is what kittens do to their mothers when nursing to stimulate milk production. Adult cats may “knead” humans when they are feeling relaxed or are trying to calm themselves. (Advice: Keep their nails trimmed.)

“It’s like thumb-sucking in toddlers,” Udell says.

Your dog is manipulating you, but not kissing you

While dogs share many behaviors inherited from wolves, they’ve also developed a few of their own, for example, “puppy dog eyes,” the innocent look that humans are helpless to resist.

“They want to be connected to us,” says Jeffrey Stevens, director of the Canine Cognition and Human Interaction Lab at the University of Nebraska-Lincoln. “Dogs evolved certain muscles around their eyes to manipulate humans. They look at us this way, and it changes our behavior.”

Like wolves, dogs also like to lick faces. Humans think their pet is kissing them. Sorry, they are not.

“It’s how wolf puppies get food from their parents’ mouths,” MacLean says. “It also can be a sign of submission. When a lower-ranking individual approaches a higher-ranking one, it gets down real low and licks the dominant one to say: ‘I’m not a threat to you.’ ”

There are some behaviors researchers can’t explain, such as “Zoomies,” the term often used to describe frenetic and seemingly random movement by a dog, likely an energy release.

“My dog runs around in crazy manic circles with her mouth open, her tongue out, ears back and butt tucked in, and if I mess with her while she’s doing it, she gets even more hyper,” Byosiere says. “She’s getting something out of her system and can’t focus until she does this. But we have zero science on this.”

One of Johnston’s three dogs “tap-dances,” she says. “When he gets excited, he taps with his front paws, then he jumps up on all four feet and spins around in a circle in midair,” she says. “He does this when he is excited or happy. I don’t know where it comes from.”

Smell can be a great motivator

As for Bella, the dog who preferred Amazon boxes over all others, the explanation seems to be her great success in sniffing out the snacks they contained: She smelled protein bars in the Amazon packages. After ripping her way in, she ate almost all of them, except for the few she stuffed behind the sofa cushions for emergencies.

“She was very fastidious about it,” says Jeffrey Levi, professor of health management and policy at the Milken Institute School of Public Health at George Washington University, one of Bella’s people. “She never eats the wrappers.”

Little Bit, the sock-addicted cat, was also apparently motivated by smell.

“Many animals carry around socks and shoes,” Udell says. “Humans produce smells on the bottoms of their feet, so if you want to get closer to your human, there’s nothing like a good smelly sock.”

This seems right to Cathy Miller, Little Bit’s human companion and an acupressure practitioner living in Boulder, Colo. Miller had to warn guests “to zip their luggage at night,” she says. “We were just glad her fascination wasn’t with underpants.”