Dr Caitlin Creak

Whether you love her or hate her, truth is stranger than fiction.

One of the first examples that I wanted to talk about is actually a close relative to us and has a track record nearly as kinky as our own, the bonobo.

They have such frequent sexual interactions that scientists often struggle to differentiate between a sexual interaction and a social interaction.

It's actually driving the cohesion of their social structure, which is a matriarchy.

So it strengthens those social bonds within this group.

They have very distinct clitoris where it's actually quite attractive to both males and females.

So this is one of the first recorded instances of a same-sex pairing driving the evolution of a physical trait, which is really cool.

Once they've had a female-female pairing, same-sex interaction, oxytocin, which is our cuddling bonding kind of hormone, is actually in higher quantities in females after a same-sex interaction.

It's in lower quantities after a male-female pairing.

That then comes across behaviourally in that when the lesbian pairs have just had sex, they're like, yeah, I want to be close to you.

I want to be in arm's reach, that kind of thing.

But when they have had sex with a male, they're just like...

Okay, thanks for that.

Guerrillas have been recorded doing every single homosexual mating behaviour under the sun, but I'm going to focus on one specific group.

This group of boys was in the Virunga National Park, so that's on the border of the Democratic Republic of the Congo and Uganda.

In this group, two silverbacks, the dominant group leaders.

They were called Peanuts and Beats Me.

I didn't name them.

Within this all-male group of gorillas, the two silverbacks were very possessive and selective of the smaller males that they were choosing to mate with.

All the smaller males, they were having sex all over the place with each other.