By Dr. Becker
Because dogs and wolves are so genetically similar, humans have made assumptions about the sensory development of young wolves based on what we know about the maturation process of domesticated puppies.
However, researchers have noted some interesting early developmental distinctions between wolf and dog puppies that could explain why adult wolves remain wild, while dogs so easily grow into their role as companions.
New doctoral research published in last month’s issue of Ethology1 fills in some of the knowledge gaps about early wolf vs. puppy development. University of Massachusetts Amherst evolutionary biologist Kathryn Lord’s doctoral research suggests the different behaviors of adult wolves and dogs are linked to early sensory experiences and the critically important four-week period of socialization.
An Important Distinction Between Wolf and Dog Pups is Uncovered
Lord’s study involved weekly measurements of the response of 7 wolf pups and 43 dog pups from age 2 to 7 weeks (a 5-week period) to familiar and brand new sights, sounds and smells. In addition, 11 wolf pups were evaluated for orientation toward sights and sounds during 2 hour sessions, 5 days a week, from 2 to 8 weeks of age (a 6-week period).
The results show that on average, wolf and dog puppies develop their sense of smell at 2 weeks of age, their ability to hear by week 4, and their ability to see by 6 weeks. However, the ability to walk and explore their environment begins at different times. Wolf pups begin walking and exploring at 2 weeks when they are still blind and deaf; dog puppies don’t begin these activities until about week 4.
Wolf Pups Begin Exploring the World Before They Can See or Hear
What this means is wolf pups enter the critical period of socialization at two weeks with only their sense of smell to guide and inform them.
According to UMass Amherst:
This information reveals the very different way wolf and dog pups experience the world during the critical month-long period of socialization, and according to researcher Lord, probably explains why their behaviors are different as adults.
“When the socialization window is open, 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.”
Timing of Socialization Could Explain Why Wolves Can't Be Domesticated
That wolf pups are blind and deaf when they begin to learn about and interact with their environment at two weeks of age is a revelation in light of what we understand about the significance of the socialization period.
“When wolf pups first start to hear, they are frightened of the new sounds initially, and when they first start to see they are also initially afraid of new visual stimuli,” says Lord. “As each sense engages, wolf pups experience a new round of sensory shocks that dog puppies do not.”
Dog puppies begin their socialization period only after all three senses – sight, sound and smell – are available to them. At two weeks, dog pups are no more than little lumps of inert fur that wake up just long enough to crawl to mom and nurse. Wolf pups at the same age are not only able to stand, but are already walking, doing a bit of climbing, and exploring.
According to Lord, the dissimilar development-related experiences wolf and dog pups have during the socialization period predicts their ability to form attachments to other species, in particular humans.
Lord believes the difference is probably not in the gene itself, but in when the gene is turned on. She says:
“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.”
It seems nature has arranged it so that wolf pups are prepared to survive in their world earlier than domesticated dogs are, but with that readiness comes a greater level of fear and aversion to other species and unfamiliar sights, sounds and smells.