July in Madagascar is cold. Cold and dry. It goes like this: The days of austral winter are usually gorgeous, hovering around high 60s/low 70s F, with few clouds which the team takes full advantage of by basking in the warm sun when we are not traipsing around the forest digging up lemurs (stay tuned for the next installment for the deets!). Around 5 pm those same clouds blaze brilliant orange, reflecting the last remaining sunlight in an overly dramatic fashion. Sunset, you’re such a show-off.
And then? Sun down = temperatures plummeting. It feels as though it drops 20 degrees in a matter of minutes. July of 2013? 50 F and raining. At our field site in the central-eastern high-altitude rainforest, April – September is distinguished as the “dry” season. It still rains on occasion, although far less than during the “rainy” season. So, why is this important for our research, and hibernation in lemurs, in general? Often times, hibernation in the tropics (and it happens more often than most people realize) occurs because resources (food and water) become scarce during the dry season. However, photoperiod changes (switching from summer to winter) and temperature also play a major role. This is one of the great mysteries of hibernation. What is the primary trigger? Are there multiple triggers? What tells an animal that it is in their best interest to “hole up” for the winter? Regarding rainfall and tropical hibernation, it seems as though resource limitation may be one of the key components. In fact, some parts of Madagascar experience virtually zero precipitation for 8 months out of the year! Zero! So, rainfall during the “dry” season? July, I say to you, “Go home. You’re drunk”. Also, much to our frustration and joy (can anyone say bittersweet?), this year’s temperatures have been record-breakingly low, as I mentioned in a previous post, even experiencing below freezing temperatures. Good for hibernating lemurs. Bad for humans studying those hibernating lemurs who curl up at night in tents.
The day after we took our laborious journey to the field site and settled in, our first order of business was to find our hibernating animals. Back in March of this year, Marina and I spent countless, sweaty, lung-busting hours trapping and collaring all the dwarf lemurs we could get our hands on. March is considered the “active” (i.e. non-hibernation) season, as the animals are feeding excessively and getting nice and chubby in preparation for hibernation. The collars we place on them, when we get them in hand, are temperature-sensitive as a means to log a continuous record of skin temperature throughout the year, as well as being fitted with radio trackers. This makes it uber-convenient to find them when they hole up underground for up to 6 months of the year during hibernation.
On the fateful morning in question, we spent 6.5 hours scouring the forest looking for our animals cozy in their underground hibernacula. In theory, this is an easy task. In reality, it is not. Dense brush, slick mudslides, broken and uprooted tree trunks, creeping lianas, and young bamboo with their evil defense mechanisms all have the capability to present some very interesting obstacles to scramble over and under. And did I mention that since our campsite is situated in a valley, most of the trails go uphill? In addition, in some places the soil can feel quite spongy, easily tripping me up, but also makes me wonder if there is possibly a hibernating lemur underfoot. I’ve already gotten well-underway on my collection of bruises that will, no doubt, form the basis for a game of connect the dots on my arms and legs. The next order of business for the day? Giving myself a concussion.
Walking along merrily, focusing intently on my foot placement like clumsy people ought to do, unbeknown to me a giant tree trunk “magically” appeared. I was, of course, supposed to duck under it. Did I see it? Nope. But my head sure felt it! I smacked into that thing so hard that I fell to my knees and saw stars lighting up the tunnel that was forming in my vision. And I always thought “seeing stars” only happened in cartoons. Guess not. Now, I’m no Newtonian physicist, but if I recall correctly from 7th grade science class, in order to calculate the force of impact my head experienced, I need to take Mass x Acceleration. Right? Force = M x A? In addition to stumbling over my feet, the trail was also sloping downward, so I also happened to be falling the moment my head hit. So, roughly 130 pounds times 9.8 meters/second squared should give me the force? Something tells me this is wrong. Is this calculation only valid in a vacuum? Or if my head is detached from my body to really take into account the acceleration of something truly pulled only by gravitational forces? Regardless of my futile attempts at physics, all I can say is, “OUCH“! I spent the rest of the hike back to our camp in a nauseating stupor attempting to do the simple task of placing one foot in front of the other. Clumsy girl strikes again!
It is, quite literally, a jungle out there!