The month that makes the difference between wolves and dogs
Behaviors shaped by earliest sensory experiences and a critical period of socialization
Source: HyperLemon via Flickr
Dogs and wolves have always seemed amazingly similar, with one huge difference: Dogs are naturally and easily domesticated, while wolves would like to hunt you down in a pack and eat you.
Why that is always has been a bit of a mystery, but now researchers at the University of Massachusetts at Amherst believe they may have figured out why wolves are generally resistant to domestication.
It has to do with two interrelated things: How their senses interpret the world in the first few weeks of life, and how they process information during an early period of socialization that essentially shapes individual members of both subspecies for life.
According to evolutionary biologist Kathryn Lord, who did the research as part of her doctorate at UMass, biologists already were familiar with some developmental differences between dogs and wolves, particularly the ability to walk (wolves do it earlier).
Lord's research involved studying the responses of seven wolf pups and 43 dog puppies to a variety of new and familiar sounds, smells and visual stimuli, testing them on a weekly basis. While she confirmed that wolves and dogs develop their senses at the same time, Lord's study "also revealed new information about how the two subspecies of Canis lupus experience their environment during a four-week developmental window called the critical period of socialization," UMass says in a statement.
During this period, according to UMass, "Wolf and dog pups begin walking and exploring without fear and will retain familiarity throughout their lives with those things they contact. Domestic dogs can be introduced to humans, horses and even cats at this stage and be comfortable with them forever. But as the period progresses, fear increases and after the window closes, new sights, sounds and smells will elicit a fear response."
Through observations, Lord confirmed that both wolf pups and dogs develop the sense of smell at age two weeks, hearing at four weeks and vision by age six weeks on average. However, these two subspecies enter the critical period of socialization at different ages. Dogs begin the period at four weeks, while wolves begin at two weeks. Therefore, how each subspecies experiences the world during that all-important month is extremely different, and likely leads to different developmental paths, she says.
Amazingly, wolves begin their period of socialization without vision or hearing, relying on their noses and sense of touch as they walk around at just two weeks old. According to Lord, this is new information. "No one knew this about wolves, that when they begin exploring they're blind and deaf and rely primarily on smell at this stage, so this is very exciting," she says.
The bottom line is that, genetically, wolves and dogs are virtually identical. Yet as Lord explains:
"The difference may not be in the gene itself, but in when the gene is turned on. The data help to explain why, if you want to socialize a dog with a human or a horse, all you need is 90 minutes to introduce them between the ages of four and eight weeks. After that, a dog will not be afraid of humans or whatever else you introduced. Of course, to build a real relationship takes more time. But with a wolf pup, achieving even close to the same fear reduction requires 24-hour contact starting before age three weeks, and even then you won't get the same attachment or lack of fear."
So for all you people who dream of having a for-real wolf as a pet, it's not that easy. Best to settle for a Siberian Husky: They look close to the part, and will present enough behavioral challenges (don't let one off its leash or you'll regret it) to make it feel like a "wild" animal.