Why are wolves forever wild animals, while dogs can be domesticated?
Dogs and wolves share very similar genetic makeup, which poses a challenge for biologists to understand why wolves remain highly wild while dogs readily become “man’s best friend”.
Currently, research by evolutionary biologist Kathryn Lord at the University of Massachusetts Amherst suggests that the different behaviors between dogs and wolves relate to their earliest sensory experiences and critical periods of socialization. Details of this research are presented in the journal Ethology.
Until now, scientists have known very little about the sensory development in wolf pups, and assumptions are often extrapolated from what is known about dogs, Lord explains. This may be reasonable, except that scientists have found significant differences in early development between wolf pups and dog puppies, primarily in the timing of mobility, she adds.
To clarify this, she studied the reactions of 7 wolf pups and 43 dog puppies to familiar and novel scents, sounds, and visual stimuli, testing them weekly, and found that they develop their senses simultaneously. However, her research also reveals new insights into how the two subspecies of Canis lupus experience their environment during a crucial 4-week developmental window called the socialization period, and new events that could significantly alter understanding of the developmental processes of wolves and dogs.
When the “socialization window” opens, both wolf and dog pups begin to explore and investigate without fear, and they will retain familiarity throughout their lives with the things they encounter. House dogs may become familiar with humans, horses, and even cats during this period and remain comfortable with them indefinitely. But as development progresses, fear increases, and after the window closes, new sights, sounds, and smells will elicit fearful responses.
Through observation, Lord has affirmed that both dogs and wolves develop their sense of smell by 2 weeks old, hearing by 4 weeks old, and vision typically by around 6 weeks old. However, these two subspecies enter the crucial socialization period at different ages. Dogs start around 4 weeks, while wolves start at around 2 weeks old. Therefore, how each subspecies experiences the world during these critical months is distinctly different, and it seems to lead to different developmental paths, she says.
Lord first disclosed that wolf pups are not yet seeing or hearing when they start to venture out and explore their surroundings at two weeks old. “No one knew this about wolf pups, that when they start exploring, they’re not seeing and hearing, and they’re exploring their world primarily through smell at this point, so that’s really fascinating,” she noted.
She further explains, “When wolf pups first hear, initially they’re afraid of the sounds, and when they first see, they’re also afraid of new visual stimuli. With each sense coming online, wolf pups go through a new round of sensory shocks that dog pups don’t have.”
Meanwhile, dog puppies only start exploring and walking after all three senses of hearing, smell, and sight are active. Overall, “The differences between dog pups and wolf pups in their early weeks are quite surprising, showing how they are similar in terms of genetics. Dog pups at two weeks old basically can’t stand and walk yet. But at this age, wolf pups are already actively exploring, taking strong steps with good coordination, and beginning to be able to climb small steps and mounds.”
The significant differences in developmental experiences between dog pups and wolf pups have led to distinct differences in their relationships with society, especially with humans. This new information will be beneficial for managing both wild and captive wolf populations, Lord says.
