I promised myself I'd check this out when I got back.

I've known that boars kill cubs.

What I didn't know, and/or hadn't heard, was that boars (brown bears) will kill cubs so they can breed the sow(s) again. Is this right??? As I understand it, they'll kill off the cubs so the sow, having no more (or not enough?) cubs, will come into heat again so the boar will breed her? Is this right? I'd never heard it before. I just figured the boars killed cubs because they were... um... "jerks."

Basically... are the boars just doing this so they can get... um... "some action?"

I suppose, sadly, that's about how it is in nature... even with humans. In the human world, I know a woman with kids is unattractive to some guys (as opposed to some "men"). It wouldn't surprise me, then, that boars are killing cubs just... to get them "out of the way."

Anyway, I hadn't heard this reasoning before and wanted to check it out when I got back. Do you guys know of any books or articles on this subject?

Russ

Sows normally breed every other year and that's why you will see some sows with cubs the size of cocker spaniels in the spring and you will see some with cubs the size of small black bear. If a boar kills the "cocker" size cubs the sow, assuming she survives the attach on her cubs, will come in heat that much sooner.



There is a parallel in Africa with prides of lions as whenever a new male or team of makes takes over a pride they kill the cubs so the lioness will come into heat thus adding their genes to the pride. If the turnover occurs too often, the cubs don't survive to grow up....this is the reasoning behind some safari companies not shooting pride males but only allowing their clients to only shoot males that aren't part of a pride.



Mother Nature sure can be tough on the little ones.

Russ:

Tough question and no real answer. Game bioliogist have come up with this assumption, but they are guessing. They have nothing to back it up.

The other side to the story is, Bears will eat anything they can catch. Cubs are easier to catch than large bears. Bears are a lot smarter than most people think but, I doubt they can figure out, that if they eat the cubs, they will get a "little" next spring, and not have to wait until the following spring.

Na, it a bunch of crap. Bears are super intelligent, but they can't reason that far in advance. They just see a cub and think, O-Boy Food!

That's pretty much how I'd always thought about it, that it is just a "food" thing. I heard this "breeding" idea and thought... "Nahhhhhhhhhh, no way!"

I'm inclined to agree with you. I don't think bears can play chess... that is, I don't think they can think five or six steps ahead, let alone two. I don't think they're reasoning along the lines of one, kill the cubs for food, and two, get some action. I'm pretty sure it's a one-thing-at-a-time situation... "plump food morsels."

You know, it's GOT to be tough to be a mama bear... protecting your litter and all. Two cubs would be tough enough, let alone THREE... but the one we saw that had FOUR... man, how would you DO that? In a fight with a boar, how could you, as a mama bear, keep FOUR cubs in line while trying to deal with a bad-attitude boar? I am NOT a PETA person but, damn, it's just GOT to be tough to be a mama bear, protecting your young. What a life.

Also... as far as mortality goes... these mamas we saw were on steep slopes. We often saw a cub, now and then, go tumbling down the hill for a ways, before it would recover and return to mama. I have to figure that sometimes cubs get buried under avalanches or take fatal spills down ravines and such. Again... what a life.

Back to the original theme, though, I can't help wishing the animal "rights" people who want to protect those "cute" bears from hunters... could see a big male bear kill a cub or two. Maybe they wouldn't mind us "evil hunters" plugging the boars.

Wait a minute. I'm applying logic to bunny-huggers. Sorry.

Russ

Russell - I read your trip report, it is unfortunate that things didn't work out (especially that late night attempt at getting the pizza ) Good luck and safe hunting on your upcoming Manitoba hunt - KMule

Russ, this is a for sure thing in some species - lions being the best known. Chimps too as I recall. With bears - I dunno. Possibly. But breeding is seasonal and as I recall, the cannibalism is not. So, it's not an immediate thing but something that is delayed, if that is the "reason" for it.

The term "reason" is a bit problematic here anyway. It implies the sole or at least ruling evolutionary explanation for the behavior. There may be other "reasons" than breeding such as simply food or territory protection.

I have seen some unbelievably gruesome photos by a bear biologist of a boar killing a sow in a prolonged battle while the photographer was stuck in a small thicket and no way to get away unseen. The sow lost. Certainly, the boar did not get any breeding opportunity in this instance. These were, far and away, the most intense wildlife photos that I have ever seen.

Brent

To my knowledge only cats, big and small are induced ovulators, meaning the presence of a male and no young will cause them to breed, many of you have seen this in studies of African Lions especially when a new male takes over the pride. The new ruler will kill all young it can catch and run off the others, this will end the genes of the louser male and cause the females to go into season allowing his genes to tkae over.

As far a bears go this is not the case since they can only go into season in the spring, after they get bred the sperm is held in suspension until hibernation when fertilization occurs therefor the cubs are born while the mother is semi hibernation. The presence of the male bear killing young as far as I know including his own off spring is a results of survival of the best meaning the best and strongess female will be successful in the rearing of offspring. Some believe infancide by male bears is just a way of eliminating competition among the large predators but if this was true they would kill or attempt to kill any and all female bears.
It is true the large grizzlies do not produce cubs every year unless they have loss their young from the previous year so the killing of cubs will not necessarily allow the male to breed.