Female koalas indulge in lesbian "sex sessions", rejecting male suitors and attempting to mate with each other, sometimes up to five at a time, according to researchers. The furry, eucalyptus-eating creatures appear to develop this tendency for same-sex liaisons when they are in captivity. In the wild, they remain heterosexual. Scientists monitoring the marsupials with digital cameras counted three homosexual interactions for every heterosexual one. "Some females rejected the advances of males that were in their enclosures, only to become willing participants in homosexual encounters immediately after," say the researchers.