I read a shocking article below. Sex between monkey and deer has become common in a particular area.
Independent: Sex between monkey and deer may be a new 'behavioural tradition', scientists say
Sexual interaction between different species is deemed as a taboo in every traditional culture as far as I know. It is called bestiality and considered as an inappropriate act. In recent years, bestiality is also deemed as abuse against animals. Even in abnormal sex lovers, bestiality as a play is uncommon.
Therefore, I was so surprised to know animals are also attempting interspecies sex. More surprised, this is not the first case of such behaviors, according to the article above. Between king penguins and fur seals, as well as cats and dolphins, similar behaviors are observed.
Intriguingly, monkeys and deer are mutually enjoying the sexual intercourse, different from other species. Thus, young female monkeys are fond of experiencing sexual acts with deer. Researchers have found there are some advantages in this odd behavior such as alternative glooming. In this sense, these two species are in a symbiotic relationship. We should not deem their acts as immoral based on ethics in humans.