Washington: Ancient polar bears with surprisingly large penis bones suggest that they had infrequent but long-lasting sex sessions, it has been revealed.
According to researchers who studied a collection of penis bones from an extinct species of bear, named Indarctos arctoides, the penis bone size mattered to ancient bears as the females assessed their mates on the basis of their size, Discovery News reported.
Penis bone, formally called a `bacula`, which helps animals keep their penises erect for intercourse, doesn`t exist in the bone structure of the human man, but it is found in many other mammals, including chimpanzees and gorillas.
The researchers found penis bones in five fossils that belonged to the large primitive bear, which roamed Europe during the Late Miocene, in the Madrid Basin in Spain.
According to the study led by paleobiologist Juan Abella, of the Autonomous University of Barcelona, the fossil record prove that the male Indarctos arctoides was much larger than the female, which is in contradiction with previous research that suggested that bear species with strong sex differences tend to have shorter penis bones and mating systems.
However, the relatively long bacula measuring 9.1 inches suggests that it was a sexually selected trait that females used to assess mate quality.