California Sea Lion Baculum

KO-500 $34.00

The baculum is a bone located in the penis of several mammalian species. Among marine mammals, this includes polar bears, sea otters, seals, sea lions and walruses. Described as the "most diverse of all bones" its size and shape varies dramatically in male mammals where it exists, and its characteristics may be used to distinguish between similar species. For example the bacula tip shape differs between the California (bifurcate tip) and Stellar Sea Lions (circular tip). One study investigating why some mammals do and some do not have this bone suggests that the presence of this bone correlates to prolonged intromission and confers an advantage in species where males face high levels of competition for females after mating. This study, by Matilda Brindle Dept. of anthropology, University College London (2016), found that the baculum first evolved in mammals between 145 and 95 million years ago.