ABSTRACT
Understanding reproduction in cetaceans is paramount to our knowledge of dolphins and whales and how they fit into the marine ecosystem they inhabit. Without extensive knowledge of reproductive cycles, it is nearly impossible to manage any species, let alone ones that are pelagic or migratory across vast oceans. Much of the early work on the reproduction of cetaceans was observational (e.g., an abundance of animals with calves were noted at a certain time of year in a given area) or descriptions of the gross morphology of reproductive tracts from whales and dolphins taken through whaling or as by-catch in fisheries. This gross anatomical and morphological work is credited with elucidating the generalized reproductive cycles of whales and dolphins; however, advancements in endocrinology refined the ability of researchers to 1) measure the onset of sexual maturity, pregnancy and other reproductive states and 2) correlate the response of individual whales to changes in their environment.
