How much energy do Steller sea lions use to stay warm?

One of the major energetic costs for sea lions living in Alaska may be thermoregulation. Steller sea lions inhabit the northernmost range of all 5 species of sea lions, and forage in waters that range in temperature from a high of 15°C in summer to near freezing in winter. Researchers have been constructing theoretical models to predict how much heat sea lions lose at various water temperatures.

Kate Willis is working on this piece of the energetic puzzle with Steller sea lions at the Vancouver Aquarium Marine Science Centre and the Alaska SeaLife Center. She is a visiting researcher from the Laboratory for Applied Biotelemetry & Biotechnology (LABB) of Texas A&M University in Galveston.

The exchange of heat between an animal's body and its environment can be expressed in terms of heat flow, also called heat flux. Kate is using animal-borne heat flux sensors to measure the amount of thermal energy that Steller sea lions lose in cold water.

Attaching the heat flux recording system to Sitka, a female Steller sea lion.

The ultimate goal of the study is to quantify heat loss over a range of water temperatures, water flow speeds, and animal behaviors. When completed, the study will assist researchers in estimating how much energy is needed by Steller sea lions to stay warm in the cold Alaskan waters.

24 June 2002