Scandal, promiscuity, and…true love?

When looking at the mating rituals of some animals, the behaviours can often seem scandalous, gross, or just plain odd to us. But what really is ‘normal’ behaviour? Because when it comes to the animal kingdom, anything goes.

This month a study published by the University of Oxford, found that female fruit flies will mate with a male, and then move on to mating with its brothers – something that I’m sure would be worthy of a great Jeremy Kyle episode! The study aimed to look at the mating behaviours of the fruit fly by taking an individual and giving it an option of two mates. Once the choice was made and the deed done, the scientists would then give the same fruit fly a new set of choices to mate with; a suitor from the same family as their previous mate, or a suitor with no relation to their previous mate.


A Queensland fruit fly

The scientists interestingly found that the males and females had completely different approaches to the mating game. The males tended to choose the mysterious, new mate presented to them each time, rather than keeping it in the family and mating with essentially their ‘sister-in-law’. However, females showed the opposite response. Why this occurs is still a bit of a mystery but imagine if the same occurred in humans! We would have far more bust ups between brothers on our hands.

Promiscuity in the animal kingdom is common, with the majority of individuals moving from mate to mate, or sleeping with many mates at one time. For example in elephant seals, the dominant male of the group will impregnate up to 50 females in one breeding season. Although this is a reward I think they deserve after fighting so intently to gain these privileges. The great David Attenborough explains below:

However, there are still many examples of species that show behaviour similar to humans and ‘mate for life’*. In fact, a study published this month from the University of Pennsylvania showed that owl monkeys do not cheat on their partners – something even us humans can’t vouch for.

The scientists took 17 owl monkey couples and carried out a paternity test on their offspring to check genetically who their fathers were. The results of the genetic tests revealed that every owl monkey had actually been completely faithful to its partner. Dr. Fernandez-Duque who has been studying the couples for 18 years, explained “In the 18 years…we never witnessed a little sneaky copulation with a neighbour, or that one partner that dashed off for some time. So in that sense we were not very much surprised by our results. But true genetic monogamy is very rare. We would not have been surprised if there had been at least one non-pair infant, but there were none.”

The scientists have put this rare mating behaviour down to the way in which males care for their offspring. Often in the animal kingdom the females are the primary carers of offspring and the fathers show very little parental care behaviour. But this is not the case in the owl monkey, where the fathers regularly carry their children on their bodies, play with them and feed them. The scientists explain that by carrying out these parental duties and sharing the work load between the mother and father, the couple spend much more time together and this leads to the monogamy observed.

Let me know what you think about the two very different studies discussed today – comment below!

* Contrary to popular belief, lobsters do not actually mate for life. So Phoebe is actually scientifically incorrect when she tells Ross on Friends that Rachel is his lobster. Lobsters are actually pretty promiscuous little things, but then again Ross and Rachel did end up together so what does it matter in the end!

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2 Responses to Scandal, promiscuity, and…true love?

  1. Jo says:

    Awww man. I always loved that quote from Friends.
    Great article though 🙂

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