Well, it seems to be starting to be spring time around here. There are lambs leaping around in the field outside my window, a lot of very noisy starlings are using my hay to build nests in my barn, and I am sure I saw a bee fly past yesterday… So I thought I’d write about the birds and the bees.
It’s another example of an area where we can learn about horse behaviour by looking at human behaviour, but possibly not in the way you might think! One of my former university colleagues, now retired, was a lovely man who studied Developmental Psychology. He was married to another psychologist, and their first child, a boy, was born as the late 70s turned into the early 80s, a time when right-on psychologists spent a lot of time thinking about gender equality and world peace. He and his wife decided that they didn’t want to impose any expectations about gender or any stereotypes on their little boy, so they went out and bought lots of beautiful educational toys – but no Action Man and no guns. Their little boy played happily with the lovely toys until one day, they found him and a visiting friend playing a very warlike game that involved shooting each other and dying dramatically – using guns they had built out of Lego.
We are all born with our bodies and our brains already set to male or female. As children, one of the things we learn very early on is to distinguish between male and female, and most parents have good stories to tell about the awkward questions they’ve had to answer about the differences between boys and girls. These awkward questions often extend to other species too, and parents need to be prepared with good answers if they take trips to the countryside in spring!
Even long before puberty, boys and girls act differently. Boys tend to like rough and tumble play, girls tend to like involved games that have a lot of talking and social interaction. Boys like taking things apart, girls like making things. I am first to acknowledge that it isn’t always cut and dried and that there are huge variations between things that different girls like and things that different boys like, but as a general rule, it is clear that boys and girls behave differently and that we can see this from soon after birth.
Most people know that hormones have an important role in sex, and they can name at least one or two sex hormones. Testosterone usually the first one mentioned, but oestrogen and progesterone are also fairly familiar ones. There are other hormones that have a very important role in sex, but they’re ones that people don’t tend to think of as sex hormones. These include oxytocin, vasopressin and prolactin. The important thing to know about (all) sex hormones is that they aren’t just involved in sex – they’re involved first of all in organising our brains so that they’re either male or female, and then, after puberty, into making our male and female brains activate sexual behaviour. Most of them have other important functions in the body that have nothing to do with sex.
So how does this relate to horses? Well, lots of us own geldings. Many of us think of them as being sexless: mares are female, and stallions are male, but geldings occupy a sort of no-man’s land! We can be surprised (and sometimes displeased) if our gelding does anything to demonstrate their maleness or sexuality.
Like humans, horses are identifiably male or female at birth. Besides the external sex organs, a colt foal is born with a brain that has already been “masculinised” by the effects of male sex hormones before and just after birth. So they are born – like human boys – programmed to do all kinds of boy behaviours. Rough and tumble play is one example: fillies prefer games that involve play chasing, especially when they can match their friends stride for stride. Colts like nipping each other, rearing and wrestling. Colts are hardwired to learn about stallion behaviours: they quickly learn how to chase and herd, and they also practice male sex behaviours like play mounting other horses. They’re like pre-adolescent human boys. They understand that colts and fillies are different, and that mares and stallions are different. What they don’t know is why that might be important to them. They’re not sexual beings, but they have clear gender identities. These male behaviours are the result of having a “male brain”.
At puberty, the brain triggers the release of sex hormones that cause the body (and the brain itself) to mature. This happens very obviously in humans. It happens in horses too: the sex hormones cause the development of secondary sex characteristics: e.g. colts suddenly developing a deeper note to their whinnies. Sex hormones also direct energy into building muscle and bulk rather than height: e.g. stallions develop crested necks and compact muscular bodies. The hormones also cause primary sexual characteristics to develop: in male horses, the penis and testes take on an adult shape and size.
Young horses gelded before horsey puberty remain like pre-adolescent boys. They have “boy soprano” whinnies, they grow tall and gangly rather than compact and muscly, they remain more playful and they also remain fairly oblivious to the scent and behaviour of a mare in season. It doesn’t mean they aren’t interested in mares. They know – just like pre- adolescent boys – that mares are an important part of the social group, and they know and understand their own role in a group of horses. So they are more likely to be the watchmen, they are more likely to want to head off newcomers, and they are more likely to try to herd and collect the group. Lots of geldings, mine included, are notorious bottom biters and rug rippers. They drive other horses from behind as a stallion does. They’re also more likely to engage in play with young colts and fillies (mares are usually too busy for this!). If they’re gelded before horsey puberty, even administering testosterone won’t make them respond to in-season mares, because their brains and bodies have never matured enough.
However… and it’s a big however! Like pre-adolescent boys, they’re still quite interested in their own bodies. And this is where the hormones I mentioned earlier have a role. Many of us have heard of oxytocin. It’s often called “the cuddle hormone” in the popular press, because it seems to be associated with hugs. What’s less well known is that it plays a key role in most male mammals in getting and maintaining an erection, and its release also triggers other hormones that make us feel good. So obviously, it’s involved in sex! But it’s also released when mothers hold and bond with their new baby, and when we hug or get a nice massage. In fact, it’s there in any situation where we connect in a social, pleasurable but non sexual way with others. The important thing to know is that oxytocin is not manufactured or released by the testes. It’s made in a part of the brain called the hypothalamus. So even geldings continue to have the ability to get and maintain erections, regardless of whether they have testosterone circulating in their bodies. It’s just that it’s not triggered by the scent or behaviour of mares: it’s triggered by pleasant social interactions and relaxing situations.
Have you ever noticed your gelding dropping his penis (and even getting an erection) during physiotherapy or other bodywork, or while you groom him? The combination of touch and a social element is what causes this normal behaviour. The penis has lots of small cells that are activated by oxytocin, and in fact the hormone can be used to help treat sexual dysfunction in humans. Young geldings will often drop when snoozing together in groups, but also during social play and when grooming each other. In human males, increased oxytocin levels are associated with social bonding, the development of trust and (although it’s difficult to measure) increased empathy – the hormone seems to help us find ways to live together harmoniously in groups. In addition, oxytocin is what allows geldings to masturbate. If you haven’t seen your gelding do this, he’s probably just a bit shy! It often happens when a horse wakes up after a snooze, especially on lazy sunny days, and again, it’s perfectly normal. We’ve made sure geldings aren’t interested in mares by removing the drive to court and mount a mare that comes from testosterone, but that doesn’t mean they’re not interested in feeling good! The exception to this is late gelded horses – if a horse is gelded after “puberty”, all he’s lacking is testosterone. He can respond to, court and serve a mare if we give him a shot of testosterone (and even after gelding, testosterone is still produced by the adrenal glands). These kinds of geldings often do cover mares, especially during the springtime, but because they have no testes, they have no sperm that can result in foals.
So the main message of this week’s blog is that there’s behaviour associated with what sex you are, and then there’s sexual behaviour. A gelding is male, and will behave like a male horse. Depending on when he was gelded, he will show either no interest or little interest in a mare when she’s in season, but the lack of testosterone doesn’t mean that he doesn’t have other sex hormones and other types of sexual behaviour. So lets take an openminded approach to gelding sexuality… and if you’re interested in hearing about mares, mareishness and hormones, click the “follow blog” button at the top of the page, because I am going to discuss it next week.