As Fall approaches, wolf dispersal is an important topic to discuss particularly with male wolves, because this is a season when they routinely leave the pack. Competition for food is increasing as this year's pups are growing so quickly and need more food. The yearling and older males are experiencing increased competition for the pack's food supply.
The Fall is also a good hunting time because many of the male ungulates (moose,elk, & caribou) are rutting. Many of them get injured and are in a weakened state making them vulnerable to wolf predation.
Another major time for male wolf dispersal is the winter and early spring. There is competition for mating rights, so younger male wolves will leave the natal pack and seek out a mate. Female wolves are not seasonal in their dispersal movements as they leave the pack anytime throughout the year.
Most wolves leave on their own when they disperse and dispersal is not usually a single event but a continum of short separations from the pack until the final, complete separation.
The average age span for dispersal is 11-24 months but some wolves have left the natal pack as young as 5 months and as old as 52 months. The younger dispersing wolves travel the farthest to establish their territory. Their new territory is usually four territories away from their natal territory. Most dispersing wolves remain within a radius of three territories from their natal territory. Wolves that establish their territory next to their natal territory are called "budders".
Three radio collared young wolves in Alaska travelled 732km from their natal territory in the Nelchina Plateau to the Brooks Range. This is the longest recorded dispersal but one Canadian female wolf dispersed from her natal pack in Banff National Park, travelled south to Glacier National Park in Montana and then headed back into Canada. She travelled all along the Rocky Mountain Trench to the Dawson Creek area where she was unfortunately caught in a trap and executed by the trapper. It is not known whether she found a mate or was a lone wolf wandering throughout this vast territory. Her travels would have exceeded the 732km trek by the Alaskan wolves.
Why they disperse
As mentioned earlier, social competition for food and mating are the primary reasons why wolves disperse but there are other important reasons for wolf dispersal.
An important result of wolf dispersal is genetic exchange. This decreases the potential of inbreeding and wolves have substantial genetic variation across North America but relatively little differentation in local populations, so long distance dispersals help to spread the genes around.
Dispersal in wolves is also an important mechanism for population regulation as the dispersing wolves seek out new territories where prey is more abundant.
While there are benefits to wolves dispersing, there are definite risks associated with this activity. Lone wolves will likely be trespassing on established wolf territories and unless they are adopted by this resident wolf pack they may very likely be killed. Both male and female wolves have to escape detection by other resident wolves to find each other. The two most effective means to find a mate is scent marking and howling and both these means can also bring death and/or injury to themselves.
Once a new pair has been established, this pair must establish and defend its new territory. The new territory must be expansive to include a large enough territory to raise pups. The new pair might adopt another wolf into the pack to assist with hunting and defending their new territory as it would be difficult for two wolves to defend a territory as large as 400 square km.
For children and adults to understand the rigors of wolf dispersal, there is a wonderful educational video game which is free to download. It is called WolfQuest and can be found at http://www.wolfquest.org/. The graphics are great and it is very educational. Parents should supervise their children when they are on this site as there is an online chat capability.
There is an interesting study done on wolf dispersal over a 18 year period in Glacier National Park. Two wolf biologists, Diane Boyd and Daniel Pletscher studied 58 radio collared wolves in this park from 1979-1997. The wolves were colonizing Glacier National Park from Canada as wolves had been extirpated from this park in past years.
Some of their findings on wolf dispersal were:
- the combined mean dispersal distance for male & female wolves was 96.3km. The wolves tended to disperse in a notherly direction back into Canada where there were other wolves. Dispersing further south in the US would mean new territory with increased prey but very little chance of finding a mate.
- they dispersed in all months of the year but males preferred the first half (Jan. - June) due to breeding and strife around breeding.
- 13 of 23 dispersing wolves found mates the first breeding season and all but 2 failed to produce pups in the first denning season.
Other studies showed that dispersing wolves were paired within 8-30 days of leaving their pack and other dispersers took 95-148 days to find a mate.
From this information, you can see that wolves have a driving force to leave their natal pack due to social competition of food and mating. They can travel long distances or move just next door from their natal territory. They are able to find mates quite quickly and produce pups the next breeding season. For all these factors, wolves have been described by biologists as dispersal pumps that converts prey into young wolves and spews them far and wide over the landscape.
Tundra & Meshach
Both have had a busy summer meeting many fine people either at resorts, summer festivals or stopping by their territory on Malcolm Island. We appreciate getting to meet everyone and it looks like they will be busy meeting school children in the Fall as I have had enquiries about Tundra's school program. Right now they are resting in their territory awating their next walk and/or next group to visit.
Good book to read
One of my favorite books on wolves is, Arctic Wild by Lois Crisler. This book was published in 1964 and chronicles her travels with her husband in the Brooks Range of Alaska in the late 1950's. They originally went to the Brooks Range to film caribou migrations for the National Geographic Society but also got involved in a study on wolves.
Lois describes her relationship with two wolf pups they raised in this remote area of Alaska. I have read many wolf studies where they have referenced Lois's descriptions of wolf behavior. When reading this book, remember that back in the 1950's wolves still had a bounty on their head, were poisoned and generally very disliked.
Lois Crisler in writing this book was able to describe the wolf as an important species in the ecosystem and it was not a ravaging beast. The book is very entertaining as well very educational.
Website
The quintessential website for wolf info is the International Wolf Centre's website, http://www.wolf.org/. This website has basic wolf info for children and adults, scientific articles and cameras to observe the captive wolves at the Centre. Feel free to browse the site as it contains way to much info to mention here.
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