Notes:
Question: Brown bears are much more closely related to polar bears than to pandas; during the breeding season, if females have cubs and there is infanticide, their vulva can be half-engorged…
Answer: Lactational amennorhea may not be complete in the bears. Vulva is very sensitive to estrogen; maybe follicles have reached certain stage, but don’t know if there’s documentation of cessation of follicular development.
Question: On a number of occasions, a female will cycle several times.
Answer: Craigheads and zoos have documented polar and brown bears that have been bred 14 days apart; these are probably distinct estrous events (multiple follicles are ovulated during the breeding season, and are ruptured in series, so the bears breed several times in a row).