Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society

You Can Sweat, But the Seals Can’t!

Emily Lam at the elephant seal colony on the Southeast Farallon Island. Biologists have been trained to safely do their research around the seals and reduce the possibility of disturbing the seals. NMFS Permit Number 21425

Congratulations to this year’s Dr. Dolittle Travel Award winner, Emily Lam from the University of California, Berkeley! Emily presented her research at the inaugural American Physiology Summit conference this past weekend in Long Beach, California (Lam E, Mouly M, Congdon C, Henderson K, Vazquez-Medina J. Physiological and behavioral responses of northern elephant seals (Mirounga angustirostris) to global change among three northern California rookeries).

Here is a guest blog describing her research:

Northern elephant seals spend extended periods of time diving to great depths, foraging in icy cold water. Their fur and, to a greater extent, blubber insulate them from the heat sinking properties of water and enable them to maintain their core body temperature. Elephant seals also spend much of their time hauled out on sandy beaches where they breed, molt and are exposed to warm temperatures and solar radiation. Many mammals sweat or move to the shade when they are too hot. Similarly, elephant seals use physiological and behavioral thermoregulation to stay cool on a warm day. They cool off physiologically using thermal windows, or hot spots on the surface of their bodies that allow them to offload heat back to the environment. They behaviorally interact with their environment by flipping sand on their bodies which acts as “sunscreen” and if the sand is wet, it facilitates evaporative cooling.

The Farallon Islands, located 28 miles off the coast of San Francisco, are home to 5 pinniped species and a quarter of California’s breeding seabirds. The turbulent waters that surround the islands and the characteristic jagged cliffs make coming ashore an adventure in and of itself. Northern elephant seals were once hunted to near extinction and have made a remarkable recovery due to marine mammal protections that were put in place. Elephant seals began to recolonize the islands in the 1970’s, however the population began to decline precipitously after major storms in the 1990’s that washed away much of the sand from haul-out locations on the Southeast Farallon Island and West End Island. We know that elephant seals rely on sand flipping to cool themselves, so the loss of sand could cause them to overheat while on land. Emily Lam, a Ph.D. Candidate in the Vázquez-Medina lab at UC Berkeley is interested in understanding what is driving seals away from the Farallon islands and wants to know if seals can utilize their physiological and behavioral adaptations to buffer themselves against habitat degradation due to extreme fluctuations in our climate. Therefore, she is investigating the relationships between environmental variables and habitat quality on sand flipping behavior and thermal window metrics in Northern elephant seals that breed and migrate within the Monterey Bay and Greater Farallones National Marine Sanctuaries.

Northern elephant seals are charismatic animals that act as sentinel species or provide insight into the overall health and viability of their ecosystem. This research aims to help monitor environmental changes in critical breeding habitats while assessing physiological and behavioral adjustments to thermal stress in potentially at-risk populations such as island colonies. Emily is conducting this work at three northern California sites, the southeast Farallon Island, Point Reyes National Seashore and Año Nuevo State Park. She is excited to determine if this research will yield results which can forecast future impacts of climate change on wildlife and identify if habitat degradation is problematic for thermoregulating elephant seals that experience significant life-history stages on land.


Codde, Sarah A., Sarah G. Allen, Dorian S. Houser, and Daniel E. Crocker. 2016. “Effects of Environmental Variables on Surface Temperature of Breeding Adult Female Northern Elephant Seals, Mirounga angustirostris, and Pups.” Journal of Thermal Biology, 61: 98–105.

Mauck, B. 2003. “Thermal Windows on the Trunk of Hauled-out Seals: Hot Spots for Thermoregulatory Evaporation?” Journal of Experimental Biology, 206 (10): 1727–38.

Noren, D. P. (2002). Thermoregulation of Weaned Northern Elephant Seal (Mirounga angustirostris) Pups in Air and Water. Physiological and Biochemical Zoology, 75(5), 513–523.

Categories: Climate Change, Environment, Ocean Life, Physiology on the Road

Tags: , , , , ,

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