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Wild Animals/Wolves and outbreeding depression



I would like to know 3 things:-

1) What are the main reasons for wolves leaving the pack. I had originally thought that the only reason for leaving was if a wolf male wanted to leave in order to be allowed to mate with other wolves, as normally within the pack, only the alpha male and alpha female are allowed to breed.

2) If only the alpha male and females are allowed to breed, does this not encourage too much inbreeding? Is there some advantage therefore that outweighs the inbreeding? What would that be?

3) People are always talking about hybrid vigor among animals for the first generation between different species/subspecies. But what about outbreeding depression, afterwards in subsequent generations, that I just found out about? The thing is, I understood that evolution mostly arises from tiny populations of a similiar DNA-strain which help new mutations to catch hold and arise in future generations.So, presumably, genetic problems always arise even with separate subspecies that can still easily interbreed. For example, wolves mixing with coyotes, jackals mixing with wolves(?)

Dear Gerald,

1.  The main reason a wolf leaves its pack is to find a mate.  But sometimes wolves are driven out of the pack by older wolves.  We can't get into their heads to know all the reasons, but these two make enough intuitive sense to cover most of the bases.

2.  If only the alpha pair breed, then their offspring will not necessarily be inbred.  The male alpha will almost never breed with his daughters.  Instead, they will often leave their original pack to seek genetically unrelated wolves and join a different pack.  The same is true for males, but they have a harder time being accepted into a new pack.

That said, genes are "selfish".  If a gene package works, then inbreeding is not necessarily a bad thing.  In fact, some species (notably Prairie Dogs) are well-documented to revert to inbreeding when environmental conditions are stable and predictable, and outbreed only when the environment becomes more unstable.  In other words, they're doing the ol' "If it ain't broke, don't fix it." with their genomes.

3.  Yes, genetic drift can be an important mechanisms for speciation.  It has evidently happened countless times over the course of various species' evolution.  So inbreeding is not necessarily always bad.  Bad genes will be weeded out relatively quickly in a small population (purifying selection), leaving the ones that "work" in that particular environment.

There is some thought that if we go far enough back, we're all the product of short bouts of inbreeding.  :)

You might find this documentary interesting:



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Dana Krempels, Ph.D.


I'm an evolutionary biologist with a passion for animals. Ask about natural history, behavior, ecology, evolution. PLEASE NOTE:

If you have found an "orphaned" or injured wild animal or bird:
Please don't waste time asking questions on the internet, as the answers may come too late. DO NOT FEED THE ANIMAL, and DO NOT HANDLE IT unless it is in imminent danger. (Many wild "orphans" are not orphans at all!) If you are absolutely sure it is orphaned, keep it warm and quiet, and find a LICENSED WILDLIFE REHABILITATOR HERE. Don't try to raise a baby yourself, or rehabilitate an injured anmal. Many a well-intentioned rescuer will do more harm than good, especially with baby birds and baby rabbits.

Without geographic location, time of day and habitat, I can't help. A clear picture is always best.

It's impossible for me to I.D. an animal call without hearing it myself.

I'm not an expert on comparative strengths of different animals (more complicated than you might think!) nor bite forces.

I refuse to answer "Which of these two animals--X or X--would win in a fight?".

These hypothetical matchups range from impossible (Grizzly Bears and Gorillas don't even occupy the same continent.) to ridiculous (Someone asked me "Who would win a fight between a Great White Shark and a tiger?").

The vast majority of animals--even the fierce and powerful--are not as warlike as Homo sapiens, and it's childish to project our aggressiveness onto them.


I have been the fortunate caregiver to a group of Black-tailed Jackrabbits rescued from the Miami International Airport, and not releasable in this area because they are not native. I also have rehabbed and released Eastern Cottontails, and am in contact with many very experienced wildlife rescuers who regularly handle injured or orphaned rabbits and hares.

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I have a Ph.D. in Biology, with main areas of expertise in evolutionary biology, genetics, botany, and ecology.

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