Such forced copulations are made preferentially on females who are laying and who may therefore lay eggs fertilized by the male. It is often assumed that animals do not have sex for pleasure, or alternatively that humans, pigs, bonoboes and perhaps dolphins and one or two more species of primates are the only species that do. In addition, Aborigines have a much more powerful scent gland in the circumanal region. Plague epidemics were caused by the plague jumping by flea from these wild rodents to rats, and from rats before or as they died to humans. Yes, some of them do.
Various neurohormones stimulate sexual wanting in animals.
Sex differences in humans
This case is one example of how the legal system in one country has dealt with the complexities of defining sex and gender and the implications of defining gender and sex. Several examples of animal behaviour that reduce mating of close relatives and inbreeding depression are described next. Traditionally, medical research has mostly been conducted using the male body as the basis for clinical studies. So, even though asexual whiptail lizards populations lack males, sexual stimuli still increase reproductive success. Bisexual behaviour was widespread and considered "both a great surprise and a shock", with big-bellied seahorses of both sexes not showing partner preference. Corals of the World.