Sex with animal dating
For the female seahorses, the important factor was how the male smelled; more specifically, the females judged the odors related to the major histocompatibility complex (MHC).
MHC-mediated odor cues can be really important in mate choice, as they help the female determine whether a prospective partner’s immune system is compatible with her own.
While this sentiment rarely plays out on the show – most couples split up during or soon-after their wedding – this romantic fancy exists for one small mammal: the prairie vole.
But instead of love at first sight, it’s love at first, well, … When prairie voles mate for the first time, their brains undergo permanent chemical changes that make them monogamous, usually for life.
Derived from the Swedish word ‘lek’, meaning “play”, lekking males all get together in one area, and use vocal, visual, physical and chemical displays to compete for female attention.
This is an example of mutual mate-choice, where both parties get to make choices based on what they’re attracted to.
When a monogamous prairie vole couple was given drugs that suppress oxytocin and vasopressin, their commitment to one another waned – they became promiscuous, and were less likely to defend and care for their partner.
A complementary experiment studied the meadow vole – the prairie vole’s doppelganger and close relative – a species that is normally promiscuous.
In fish, larger females are generally more fecund (they lay more eggs), so choosing a large lady has a clear benefit.
Females, on the other hand, thought size didn’t matter in their males. Each episode sees two pairs of strangers meet in a room furnished only with a bed and a large-screen TV.
When given oxytocin and vasopressin, meadow voles adopted the monogamous behaviours of their cousins.