Him or Her? It is not always an easy question to answer! Here you will find tips and tricks for telling male from female in both pinnipeds and cetaceans. With a little practice you should be able to determine gender in just a few seconds during your Level A exam!
He or She? Sometimes gender is easy to distinguish even at a distance and sometimes you have to get up close and examine the animal. In many pinnipeds there are a number of features that often make gender ID fairly straightforward even when the animal is rather decomposed. For example, adult male California sea lions have a bony ridge called a sagittal crest which gives them a very prominent forehead. This secondary sexual characteristic is only found in adult males and thus, can help you determine both age and sex at a distance.
Him or Her? Gender is one of the most important elements of the level A form and determining he or she is quite different in a cetacean than pinniped. In general, most cetaceans do not have the obvious secondary sexual characteristics such as the raised bony CREST that you find on the forehead in male California sea lions. Cetacean males also do not have a baculum, or bone in the penis, which is readily distinguishable even after extreme decomposition. Rather, body size tends to be the biggest difference between male and female cetaceans and often even this is not readily distinguishable. Thus, gender determination in cetaceans usually relies upon examination of the ventral body surface.
UCSC Long Marine Lab
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