Dosage of progesterone

In the females’ bellies


  • Fin whale and its calf
  • Photo credit: © GREMM

Progesterone is a steroid hormone secreted by the ovary in female mammals. By analyzing the blood, saliva, eye secretions, feces or subcutaneous blubber layer in females of certain cetacean species (killer whale, minke whale, fin whale), it has been demonstrated that it is possible to determine their stage of maturity or period of reproductive cycle. Researchers can thus identify the age at which females reach sexual maturity or even conduct pregnancy tests on them! Questions of this nature can help biologists better understand the health of populations. The advantage of this method is that it only requires a small sample that can be collected relatively easily from living animals in their natural environment. It is a relatively new and highly promising technique.