As I write, I have a lemur resting comfortably on my lap. Well, actually it’s two lemurs: a momma and her baby. These beautiful creatures, diademed sifaka (Propithecus diadema) are the focal animals for Mitch and Karen, researchers at Northern Illinois University. Mitch has been doing field work in Tsinjoarivo Forest for 12 years, studying the ecology and natural history of this sifaka population. This year, Mitch and Karen are darting animals from their focal groups and bringing them back to camp for routine animal health checks. Diademed sifakas are notorious for having a difficult time raising body temperature back up to normal after anesthesia. Thus, the NIU researchers have enlisted the help of our team to warm the animals while they recover. We, of course, jumped at the chance. How often do you get the chance to hold a wild sifaka?
As I sit here, writing feverishly and warming these rare animals, I am struck with a feeling of being truly blessed. I have seen things here that I never dreamed I would bear witness to; a mother chameleon laying eggs who flashed her brilliant colors at me when I almost accidentally stepped on her, sunsets so majestic that even the best artists would not be able to capture the striking display of color combinations presented before them, a Malagasy family who willingly and graciously allows us to become a temporary part of their family, and, of course, the once in a lifetime chance to study and obsess over, in my humble opinion, some of the most unique animal species that exist today.
I’m not telling you this to incite jealousy–that would never be my intention. Instead, I only share this to ensure that you know that I don’t take these experiences for granted. I feel lucky. Unbelievably so. I feel lucky that I have parents who support the many hair-brained schemes I have pursued (You want to spend 6 years of your life studying what?). I feel lucky that I am here with the “best of the best” researchers in their respective fields and that we continue to maintain and strengthen incredible collaborations. I feel lucky that the American Philosophical Society chose me as a recipient of the “Lewis and Clark Field Scholar” award and provided the funding for this field season. I feel lucky to be under the guidance of an advisor who gives me ultimate freedom to pursue the questions that keep me awake at night.
Good segue! What questions do keep me up at night? What driving forces influenced our research team to travel approximately 8,000 miles (give or take a few thousand) to get here? Well, the answer, I fear, can be a bit convoluted, but I’ll do my best to give you the guts of our work. Since there are so many complexities to the topic of dwarf lemur hibernation, this leads to a seemingly infinite number of unanswered questions. Answer one and you’ll open up a “can of worms” of more. But this is why I feel compelled to trudge on. The anticipation of one discovery leading to another. To tackle some of the questions surrounding dwarf lemur hibernation, we formed a team of researchers who, working together and sharing data, might be able to fill in the gaps. Needless to say, there are many hands in the pot. In this case, the proverbial pot is, of course, our dwarf lemurs that we are all so enamored with. And in this case, these hands are cooperative and quite necessary. I’m going to break it down by principal investigator and hopefully by the end, I will have painted a complete picture of cutting-edge science awesomeness.
Firstly, Andrew and Peter: Does a dwarf lemur in hibernation sleep? And the follow-up question, do those same animals have a decreased need for sleep due to the use of hibernation for up to half the year? These bold questions can only be answered via sophisticated technology that far exceeds my understanding. That is, EEG records from hibernating animals (in other words, what is the brain doing during hibernation?). This requires us to lug laptops, hundreds of batteries, and fancy USB drives called “dongles” (which, by the way, are worth more than my life) into the forest, our remote lab. These records allow us to get a measure of brain activity, heart rate (EKG), breathing rate, and muscle tone. This project is greatly assisted by our awesome undergrads Sam, Eric, and Susan (you guys rock!) and of course, Bobby, whose priority is making sure our animals stay safe and healthy.
Next up, Kathrin. Kathrin’s question? How does a hibernator, under tropical conditions, budget its energy stores? Her methodology utilizes a magic box, fondly known as the OxBox. This lovely gadget, a “portable” oxygen analyzer, magically measures the metabolic rate of our hibernating lemurs. We can then compare this data to the metabolic rate of an active animal to begin to dissect the amount of energy saved during hibernation. Basically, we put our animals into fancy-schmancy “metabolic chambers” (souped up Tupperware) and hook them up to the OxBox through a series of tubes. Dave, our handyman extraordinaire, helps Kathrin lug her magic box all around the forest. I mentioned that it’s portable, but it actually isn’t all that portable. Just ask Dave, who just today busted his face on it (Sorry, Dave!).
And now, Marina. What are the environmental triggers of hibernation in dwarf lemurs? Her scientific method of choice is a continuous monitoring and documentation of the natural history of our study animals throughout the year. She is the mastermind behind trapping and collaring our animals, recording morphometric measurements (forearm length, head width, etc), taking dental molds, and is also interested in the hormonal changes that occur throughout the year with a particular interest in…you guessed it, hibernation. She is the reason that we are all here and the glue that holds this whole project together.
And lastly, my research. What are the genetic controls of hibernation? Dwarf lemurs essentially yo-yo diet. Right before hibernation they get excessively fat. I’m talking grossly fat, sometimes more than doubling their body size. Guess where they store this fat? In their tails! When they enter hibernation they cease eating and instead switch to these tail fat reserves as their only source of fuel. Dwarf lemurs are not unique in yo-yo dieting behavior, however. Loads of hibernating species do it, from ground squirrels to American black bears. So, despite inhabiting (relatively) warm climates and hibernating under such, the question is then, are the genetic mechanisms that control metabolic economy (i.e. switching from carbohydrate to lipid metabolism) the same in dwarf lemurs as in other cold-adapted hibernators? Hopefully, I’ll have the answer to this someday! In order to begin answering this, and surrounding questions, I need to start from square one since NOTHING is known about the functional genomics of dwarf lemurs. My approach to do this is conceptually quite simple. Logistically, not so much. I collect white adipose tissue (i.e. fat) from the tails of dwarf lemurs at multiple time points throughout the year.
Enter, molecular biology! Back at the lab, I isolate RNA (transcribed sections of the genome that code for genes) and use über-expensive technology to sequence these gene-coding regions (or in other words, figure out the unique order of “A”s, “T”s, “G”s, and “C”s that make up all genetic material). This is the “transcriptome” (and your buzz word for the day). Now, the transcriptome is not static–quite the opposite, actually. It is constantly changing and turning off and on different combinations of genes in response to an organisms’ also constantly changing environment. In the case of hibernation, here is a scenario. It’s the rainy season and dwarf lemurs are merrily running about. There is plenty of food around and the hypothetical animal we are following, let’s call him “Red Bean” for fun-sies, is munching hungrily on delicious, ripe fruit, normal carbohydrate metabolism chugging away. Those genes that drive carbohydrate metabolism are turned on. Now, the dry season hits and resources disappear. Red Bean goes into hibernation (like a good dwarf lemur should) and since he is only relying on his stored fat to keep the critical physiological processes running, the combination of genes that govern fat breakdown turn on. Ideally, these two physiological states (active vs. hibernation) will have distinct patterns of genes that are expressed. Ideally. Stay tuned!
So there you have it. Our research in a very long-winded nutshell.
Oh and one more thing. I feel lucky that a small Malagasy boy gave Susan and I gifts of clay zebu that he made. And also, that I have lemur saliva on my hiking boot.
It’s a jungle out there.