By Sarah McQuate, Stefan Milne, Gillian Dohrn, and William Poor, UW News

Nursing is a major energy suck, but it’s difficult to estimate the toll for many marine mammals

Marine mammals lactate like any other mammal, but the energetic demands are difficult to measure in wild animals and thus not well understood.  Researchers are concerned that some marine mammals may not be getting enough food, which can lead to failure to reproduce and starvation. To understand the link between nutritional status and reproduction, researchers need to know what marine mammals require to rear offspring. A UW study recently published in PLOS One modeled the daily costs of lactation using data from semi-aquatic and terrestrial mammals to explore whether results could be generalized to other species, like whales and dolphins. Modeling could approximate lactation costs of certain understudied marine mammals, including seals and sea lions, but appeared unable to produce accurate estimates for whales and dolphins. Lactation costs increase over time for most animals, but seem to be higher early in lactation for marine mammals, possibly due to their fully aquatic lifestyle. The study highlights a need for other methods to fill the remaining data gap to better understand the impacts of environmental change on marine mammals.

For more information, contact lead author Elizabeth McHuron, a research scientist in the UW Cooperative Institute for Climate, Ocean, & Ecosystem Studies, at emchuron@uw.edu. Funding information is included in the paper.