Life History

A tooth elevator is used to extract dolphin teeth

Photo credit: Rich Press, NOAA; A tooth elevator is used to extract teeth, which can be used to determine the age of a dolphin. Teeth from over 30,000 marine mammal specimens are stored in the collection.

Set of ovaries showing difference from immature to mature dolphins

Photo credit: Morgan Lynn, NOAA; Ovaries are examined to study reproduction in dolphins. Sexually immature dolphins have smooth ovaries (left) while those of mature dolphins have visible scars of ovulation (middle) or occasionally a corpus luteum, which is a large gland that secretes hormones during pregnancy (right).

Life history studies describe the reproductive and survival characteristics of a species, including

  • how long individuals live
  • the age at which they become sexually mature and first reproduce
  • how often they breed
  • how long they nurse their young
  • where they forage
  • what they eat

  • Combining this data for many individuals of a species enables us to understand the lives of marine mammals and their growth rate potential, which is a critical factor in developing plans for effective management and conservation. Current life history studies at SWFSC are focused on short-beaked common dolphins, long-beaked common dolphins, and bottlenose dolphins that live offshore of California.