One of the cowboy science teams (or cowgirl science team – see photo) that I was able to spend some time with at McMurdo Station is the Weddell Seal Research Team under the direction of Dr. Jenn Burns of the University of Alaska. This multi-faceted science team spends virtually every single day during their field season tracking down tagged Weddell seals on the Ross Ice Shelf and performing a gigantic battery of physiological tests and measurements on them. Every day this group is either in helicopters (less frequently) or out on snow mobiles (more frequently) re-capturing animals that they already performed measurements on earlier in the season, in order to document their physiological changes throughout the reproductive season.
The picture below shows them in their lab space at McMurdo in a rare moment when they are all standing still. Jenn Burns, the project head, is on the left. The rest of the team shown here includes two grad students, a postdoc, two veterinarians, and a science-educator.
Jenn Burn’s project is looking at a variety of links between seal physiology and seal reproductive success. Different team members are looking at lipid levels, hormone levels, molt timing, timing of pup bearing (early or late summer), and impact of skipping a reproductive year, among many other variables that they are trying to link to reproductive success. It’s amazing how relatively little is known about Weddell seals. Regular pregnancy tests used in other mammals don’t work with the Weddell’s, so the team has implemented novel ultrasound procedures for determining if a seal is pregnant and for characterizing the developing fetus – which they also perform during the time that they work with each anesthetized seal out on the ice. Even significant aspects of the reproductive anatomy of the Weddell seals are relatively uncharacterized, and so some of that is also being documented by the team.
The precautions they take with the animals they study are quite intense: they have a permitting process that allows them to anesthetize and directly work with up to 24 seals on the ice during this window of the project, and a major role of the two veterinarians on the team is to make sure that the seal never goes into any type of distress and is successfully released after the team makes its measurements and takes their blood and small biopsy samples. The physiological samples are then processed for shipping back at their lab in McMurdo, and most of the detailed biochemical analyses will occur once the sample and the team are back in their regular lab at the University of Alaska.
As I have learned, Weddell seals are amazingly interesting animals. They aggregate in colonies, sometimes with hundreds in one colony, yet they stay relatively solitary within that colony. When they are “hauled out” and basking on the ice, each seal with be by itself with 1-2 yards or so between it and any other seal. In the water during the breeding season (mid December) the male Weddells keep and defend 3-dimensional territories – mostly linked to access points in the ice where seals can “haul out”. Females select routes through these male territories dependent on who they want to mate with. Females only give birth to one pup a season (apparently twinning in Weddells is far more rare than it is in humans). After they give birth to their pups they only care for them for approximately six weeks – after that the young seals are on their own. In the Ross Sea area right around McMurdo there are about 2000 Weddell seals that stay mostly in this region from year to year. One of the interesting inter-colony movement patterns that occurs during the breeding and nursing season is that the older (and wiser?) females will gradually move to areas around McMurdo where it is more reliably “easy” to haul out onto the ice during the season (some areas more consistently have thinner ice).
Although they will use natural cracks in the ice, the Weddells can also bore their own access holes with their teeth. They cut through the ice from below to make a hole, even shaping out somewhat of a ramp on one side of the hole where it is easier for them to haul themselves out with their front flippers. Since they have no land predators, the Weddells are quite patient and almost nonchalant about the researchers walking and working among them. Apparently other seals are not quite so chill regarding humans in their midst.
The day after day consistency and intensity of the work this team is doing is why I call them cowboy scientists – their unique combination of collecting “normal” animal data under rather extreme conditions miles out on the sea ice makes for some real adventure science.
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