Grizzly scenario

[CarbineCaleb]

Capt: Some interesting stuff there - I know that for most mammals, evolution has ensured that fertility is a function of food supply - obviously a good strategy. This is accomplished by hormones whose levels track the feeding state of the animal and act to enhance or suppress ovulation. I think there may be multiple hormonal cues, but one of them has to do with the amount of fat on the animal. Therefore, you will naturally get an increase in predator population - if they are better fed, they will have more babies.

Same thing happens with humans, by the way - hormonal changes due to high fat levels seem to be capable of introducing pubescent changes and estrus earlier, for example, and very low levels of feeding - what we call malnutrition, can completely suppress menstruation. If you are poorly fed, you will have fewer or no babies.

Just as you said, the population of the response system cannot overlay directly on the driving system - there has to be some inherent lag between the two (a phase lag), that is characteristic of the reproductive cycle rates for the animals.

Like you, I have my doubts about the predator/prey cycle business with regard to bears. While bears can eat meat, my understanding is that they get about 2/3 - 3/4 of their calories from vegetable sources (like berries), and most of the rest is carrion found by scavenging in the wild. So I am not sure how tightly coupled they'd be to "prey" populations of any kind.

However, bear population changes, regardless of the causes for them, could definitely affect attack/fatality rates. More bears mean more encounters, and more encounters mean more fatalities. Likewise, more bears means increased competition for food, which will cause some of them to move to seek out new territory where there is greater opportunity.... that will invariably cause the nomads to encounter humans in their search.

What you would need would be the other data for the candidate causes to allow them to be overlaid and correlated. I don't think this shape is just random variation, anyway.

Keep me posted! ;-)
Caleb

 

[wayneinFL]

Something that surprises me, is the wanting there to be a "reason" for the bear to predate on people. True, it isn't common in the greater sceme of things, but there isn't anything that's so special about humans that make bear magicaly avoid us at any cost. We flatter ourselves to think there HAS to be some reason or circumstance for a bear to attack a human. Maybe the ones that do, just decide they WANT to. Do they need any more reason than that? They are career predators. They do this for a living. Kill and eat stuff. Sometimes they try something different, and sometimes they realize how easy people are (usually).

I do wonder if after all of the scientists analyze shark,alligator and bear attacks and come up with all of their hypotheses and theories, if a wild animal wasn't just sitting around one day and said:

"Hmmm....I always wondered what one of those things would taste like?"

Maybe I spent too much time reading the Far Side.

As to the charts: Could it be there are more people going into bear country for recreation than before? Maybe due to more people here than before, or less public lands for them to enjoy, or that there's just a renewed interest in the outdoors? Or that we are less likely to shoot bears that come into contact with people? Or that there are more bears than before due to conservation efforts?

 

[panzer426]

its probably a combination of all of those things. more people going out there facilitating encounter, more wilderness everyday destroyed for homes and stores. and I imagine 90 ish % of people who go hiking in bear country carry a Nikon rather than a firearm? most of them are probably HOPING to see a bear up close, or just think its not gonna happen to them because if that was possible or likely the government wouldnt allow anyone in the area. most people I have talked to think that the only dangerous bears are the ones that have caused problems already, and that those bears get killed. they dont realize that most bear attacks are either caused by startling a feeding bear, or by getting too close (wether intentional or accidental) to a female with cubs. personally if I were 1,000 pounds, had razor sharp claws longer than a humans fingers, had huge jaws with sharp teeth, and had succesfully chased/faught off other enormous bears mountain lions wolves etc I would not have any second thoughts about seeing if the first person I encountered tasted good or not. if you are physically capable of eating just about anything in the forest, why would you not attack unless you had something better to do, or had experience telling you that humans are dangerous???

 

[CarbineCaleb]

From what I know, although there are occasionally bear attacks in the backcountry, the majority of bear encounters, as well as the majority of bear attacks, come along park roads, and drivein campgrounds.

Here, the bears have become used to people, and don't avoid them... in fact, because many people feed bears either inadvertently or purposely, many of these bears have come to associate people with food. Likewise, people in these areas usually are less knowledgeable about bears than backcountry travelers, and tend to do more stupid stuff. Rangers have told me that many people will feed bears, some by hand, some get out and have picture taken with bears (try to put arm around it for photo), punching bears who try to get into their cooler... just really, really stupid stuff.

I have actually seen most of my bears along wilderness roads and big campgounds. Far fewer in the backcountry, even though I spent a lot more time there.

As to bears eating people "any time they have nothing better to do"... come on - if that were the case, there'd be incredible carnage, and we would have wiped them out centuries ago, in fact.

 

[Capt. Charlie]

"Maybe I spent too much time reading the Far Side."
Naw! Why I heard just the other day that one of those man-eating grizz was wearing a pair of those pointy, pink-framed 1950's sunglasses (Gotta love Gary Larson!)

Seriously, if I've learned anything at all about Ma Nature, it's that there's always a reason. There can be random variations in behavior among individuals of a species, but consistent behavior within a species always has a reason, even if we don't know what it is. Grizzlies as a rule don't generally prey on human beings. So why the increase? Research (yeah, even statistical research [sorry Cal ]) may seem fruitless or even useless to some in the short term, but if we can find the reason, we can usually find the remedy. That would be a win/win situation. We could do more to preserve a truly majestic species and at the same time, reduce human fatalities. There are so many factors, or drivers, that it's a daunting task. If you consider the possibility that two or more factors working together are the cause for increasing attacks, then the number of factors that must be explored rises exponentially, making for an almost impossible task. Until then, though, common sense.... and a Street Sweeper loaded with slugs , should keep everyone safe.

 

[CarbineCaleb]

I will be the first to admit that statistics can be misused/misunderstood by the careless or dishonest. Having said that, there is very little that happens in science/medicine/engineering without some involvement of statistics, and as often as not, the involvement is pivotal to either discovering a phenomenon or pinning it down.

And I am not a statistician by academic department - so that's not the voice of "promote your core discipline"... my degrees all came from chemistry departments. Even coming up as a student though, I was active in other useful fields - that's where all the good stuff happens, is at the interface between fields.

 

[Capt. Charlie]

"that's where all the good stuff happens, is at the interface between fields."

THAT'S hittin' the nail on the head, Cal! By the way, I was only spoofin' ya about statistics. Truth is, I think I understood integral calculus better than I did statistics.... and I flunked calculus ,

 

[xXStarScreamXx]

Desert Eagle on my hip wityh 3 mags. 2 Frags. and a 3 1/2 inch magnum semi auto with slugs on a sling. Ohhh and balls of steel.

 

[CarbineCaleb]

Everyone has a subject that is their "kryptonite" ;-) When I first got to school, I didn't have the maturity to recognize the seriousness of why I was there, and what would happen afterwards - to me, the whole thing was just a lark! I did poorly all around. Eventually, I wised up though, and made up for lost time, and things worked out alright.

Whether or not you enjoyed your time in stats, Capt, you strike me as quite a bright guy. Noticing for example the structure in that data, even while it was in the table, shows that the lights are on, and shining bright!