In the New York Times, a piece on the ongoing Deer-Forest Study, a collaboration of Penn State Universitty, the U.S. Geological Survey, the Pennsylvania Game Commission, and the Pennsylvania Bureau of Forestry. These researchers intensely study 100 square miles of central Pennsylvania where deer roam across a series of steep, forested ridges. As part of the study they have put GPS collars on about 1,200 deer, studying things like the size of their home ranges, how their lives change with the seasons, how they react to hunting, and so on. Their main scientific interests are actually more focused on the forest than the deer, trying to figure out how large deer herds impact the environment. But sometimes they stumble on little mysteries of animal life:
Researchers from Penn State had captured and put a GPS collar on the adult male that spring in Bald Eagle State Forest, about 15 miles northeast of State College, Pa. Put a tracker on most deer and you’ll find they stick pretty close to their home range, which was true for 8917. He sauntered, stopped to forage or bedded down for a nap mostly within an undulating square mile of forest full of towering hemlock and tangled rhododendron. But on that June day, he made a one-mile beeline, hiking to the top of a rocky ridgeline, where he seemed to while away the afternoon before walking directly home.
Then, in 2015, after two mating seasons, two hunting seasons and thousands of laps around his home range, Buck 8917 died — unsurprising given he was about 4 years old. It was where he died that surprised the researchers: that same ridge he’d visited just once in the two years he’d been collared.
The blog post on which this is based is here.
Strange that both you and the post you link to frame this as a mystery, when the very post itself does a huge amount to suggest these outlier movements are the product of fleeing from predators, whether wild or human.
ReplyDeleteThe answer really does suggest itself very easily.
The first time, the deer got tracked by a predator once, it was "cornered" and couldn't flee in the direction of familiar terrain, so it instead fled up into unfamiliar terrain, hung around at the top of a ridge for several hours until it felt certain it had lost its pursuer, then it found it's way home.
The second time, the deer was again fleeing danger at the edge of its range and was unable to safely reach more familiar terrain, but it remembered how it escaped on the previous occasion, and sought out the same route to the same hiding place. Except this time, it ultimately got caught.
"Why go there to die?" the blog asks, but I think it's got things backwards - the deer went there trying NOT to die, as that worked once before when caught out in that area, but the attempt simply didn't succeed the second time.
Is there any evidence that he was shot? Wouldn't a hunter take the carcass? Attack by a predator like a bear would be unlikely to result in a slow death and probably wouldn't leave much behind. I'm not convinced by the escape theory.
Delete~Lisa the Wife
By the time researchers reached the carcass, it had been scavenged to scraps by coyotes, making it almost impossible to tell what the cause of death was.
ReplyDeleteIt was January when the deer died, with snow on the ground already, and a major snowstorm hit right around the time of death, preventing access by researchers for at least 24 hours. It could have easily been shot by a hunter and slowly bled out, with the hunter losing track of it or even simply giving up the chase because of the already bad weather plus the oncoming major storm.
It could also easily have been attacked and wounded by a predator (or predators) - likely not a bear, as it was January, and bears start hibernation between late October and December, and only emerge between March and April. It's not impossible, of course - some bears do emerge sometimes on warm days and roam near their dens, but they tend not to hunt. The big exception, of course, is a sick, injured, or starving bear, who may be driven by desperation to hunt - and which might very well manage to wound a deer, but struggle to actually kill it.
That said, far more likely would be one of the deer's other major natural predators - bobcats.
A bobcat is big enough and dangerous enough to kill a fully grown deer by itself, but they're also small enough that it's not always a sure thing, and they can be driven off if their prey fights back hard enough. Deer may not prefer to fight, but they're still quite strong, with nasty kicks that can shatter bones if well placed. It's entirely possible that after being wounded by an attacking bobcat, the deer wounded its hunter back, putting them both out of the fight, and leaving the wounded deer to escape but succumb to its wounds later.
Bobcats are also only fast in short bursts - even without actually fighting off a bobcat, a deer that manages to slip free of one has a pretty good chance of outrunning it and losing it. But again, a wounded deer might escape the initial attack, only to slowly bleed out further away.
Coyotes are also quite capable of taking down deer, usually as a pack, but in this case the scientists note that the coyotes which scavenged on the dead deer were clearly not what immediately killed it, as it had been covered by snowfall before being dug out to be eaten. And while a lone wounded deer could quite reasonably escape a lone bear or bobcat to die later of blood loss, it's exceptionally less likely to escape an entire pack of coyotes.
Personally, my money would absolutely be on a human hunter - natural predators hunt out of need, whereas a sickening number of human hunters kill merely to entertain themselves, and would be far likelier to give up on tracking an animal they merely wounded, particularly at the prospect of having to face a snowstorm.
A hungry bear, bobcat, or coyote would hardly be deterred from chasing a wounded deer by a bit of snowfall if it meant a substantial meal in the dearth of winter - but Joe Hunter is going to look at the coming storm and think to himself, "Nope, that's WAY too much work, I don't need venison burgers THAT bad, I'll just go buy some ground beef instead", then trudge back to where they parked their truck, and when they get home brag about "The One That Got Away" over a six pack of 'Lite' Beer.