The cloud forest is, as you might expect, often cloudy.
I’m in Lima now, on my way to San Diego from the eastern slope of the Andes. I’ve spent most of my time since my last blog entry looking for evidence of Andean bears in the forests of eastern Peru. I began this search by returning to a mountainside where we’d earlier seen the leftovers of a bear’s meal and where we’ve had a camera “trap” in place for several weeks. Unfortunately, the camera did not take any photos of Andean bears, but it had snapped additional species of birds and mammals. There’s clearly quite a diversity of wildlife at that site, but it doesn’t appear to be used much by bears, at least at this time of year.
The bamboo was incredibly dense at this site.
We spent a few days camping in the forest nearby, on a ridge that eventually climbs up to alpine grasslands. In other areas of their range, Andean bears are reported to use similar grasslands during some seasons of the year. Evidence of bear presence, such as feeding sites and feces, has been reported to last longer in such grasslands than in the cloud forest, so it would be interesting to look for evidence that bears use these particular grasslands. However, we weren’t able to get that far afield because of the fantastic density of bamboo. In one thicket there was more than nine bamboo stems per square meter, for a few hundred meters. Cutting a passage through the bamboo was a slow process, and although we rationed our drinking water, we eventually ran dry and had to turn back.
The diversity of canopy structure in the cloud forest
This ridge rises above the valley through which the Interoceanic Highway is being built. Periodically, loud explosions echoed off the surrounding mountains, as construction crews blasted through the cliffs, and these crashes would make us jump, even over the ringing of the machetes in the bamboo. There are parallels between the road construction and our trail construction, but we attempt to minimize our impact on the forest as much as possible. This is one of the challenges to ecological researchers: can you study a system without your activities changing the way it functions?
We’re trying.
Russ Van Horn is a senior researcher for the San Diego Zoo.
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December 16th, 2008 at 7:25 pm
Sorry to hear you haven’t spotted a bear yet. Must be disappointing after all that effort - maybe the bears don’t like the construction noise either.
December 22nd, 2008 at 4:02 pm
Most bear species are known to avoid humans whenever they can, and Andean bears have a reputation for being more shy than the others! So, although I would like to see a wild Andean bear again, I’m not too surprised that I haven’t yet, and we’ve planned our work so that we can learn about the bears without actually watching them.
December 26th, 2008 at 3:49 pm
Sorry you have not seen any bears yet. But keep up the good work Russ and please write more! I love to read your entries.Thanks for takeing the time to write your them. By the why, are bears so shy of humans if they are so strong?
January 6th, 2009 at 2:22 pm
That’s a good question, Pepsi Coke. I’d have to speculate that bears usually avoid people for one or two reasons.
First, many animals are generally wary of unfamiliar sights, smells, and sounds (and tastes). If a bear hasn’t encountered people before and isn’t a bear that usually preys on other mammals, as the polar bear does, then the bear might treat us a possible risk, and avoid us.
Second, if bears have previously encountered people deep in the forest, they’ve probably encountered hunters, because not many people venture far into the forest except hunters. If a bear has had a negative experience with a hunter, then it has probably already learned that we are a risk, and would avoid us.
These two ideas may seem contradictory, but they both rise from the same principle. Bears, like other animals, have evolved to expend energy and take risks when the payoff is worth the investment and risk, or when the cost of not doing so is too high (as when a female bear defends her cubs). Otherwise, they avoid spending energy and taking risks. Until or unless a bear learns that we’re a potential source of food, we’re just a potential risk, and there’s no reason to let us get too close.