CURRENT RESEARCH
Understanding female hormones is KEY to understanding breeding behavior.
Our research into female reproductive and breeding behavior has demonstrated the complexity of factors that contribute to breeding behavior. But to fully interpret breeding behavior we need to first understand the underlying reproductive physiology of females.
At any given time on the breeding grounds, female humpbacks in various maturational (juvenile, mature) and reproductive states (near term pregnant, lactating, estrus) are present. Where a female is in her reproductive cycle likely influences her interactions with males and affects how males respond to her presence. Without the knowledge of the female reproductive cycle, we can only speculate what these interactions mean in terms of mating and courtship.
How do we measure hormones? Pregnancy Test for Humpbacks?
To better understand the physiology driving the behaviors we see, we analyze the hormone profile of female humpbacks throughout the breeding season. Similar to humans, reproductive hormones are present and cycle in humpbacks. Certain hormones will spike during different phases of the reproductive cycle, and we can use these increases to inform us about the timing of events such as pregnancy and estrus.
Reproductive hormones are stored in the whale’s blubber (left photo) and can be obtained by taking a biopsy sample (right photo).
Whale Trust researchers are working with the University of California, Santa Cruz (UCSC) and the Southwest Fisheries Science Center, La Jolla (SWFSC) to explore whether or not steroid hormones (estrogens, progesterone) stored in a whale’s blubber layer will one day help us to detect near term pregnancy or even estrus in free-ranging humpback whales. By correlating a female’s reproductive state through hormone concentration with her behavior and interactions with males, we can better understand the circumstances that lead to mating and birth.
