I always look forwards to the first subzero morning. Coming so early in the autumn season, when summer still holds the days, it typically occurs after a clear night, which means the subsequent morning is a real beauty. Low sun, mist in the glen, everything tinged with white.
A bleary-eyed glance out of the window as I put the kettle on for a cup of tea is never enough, though. I want to both feel and smell the cold, so I stumble outside to be embraced by the frost.
Such was the scene on 13th September this year as I stumbled out, squinted and inhaled. And then, just seconds later, I heard that unmistakable sound for the first time this year. The deep, guttural and sometimes gurgling roar of a large red deer stag, sounding somewhere between a big cow and a bear. That first frosty morning had definitely encouraged some local stags to give their vocal cords an airing, indicating that the rut is on its way.
The word “rut” apparently comes from a 15th century French word meaning a noise or disturbance, and while this might be the most conspicuous aspect of it, the rut is far more than just noise. It is the mating season for red deer, although other species of deer have their own ruts too, sometimes with different timings. Roe deer, for example, have theirs during the summer, but for this piece I’m focusing purely on the red deer rut.
In Scotland it generally lasts for several weeks between mid-September and November, and some folk go so far as to tie the start of the rut to a specific annual date. You’ll see 20th September, or perhaps the 26th, cited as Latha a’ Bhuiridh, the Day of the Roaring, but pinning it down to a single day is a challenge, as there are several variables that effect deer activity, not least weather conditions, which can exaggerate or suppress rutting activity.
Very little in nature can afford to be so rigidly punctual, but given these dates are all in the same deer park, where nature’s calendar is concerned the start of the rut is clearly one of the more dependable annual events. The very fact that it is assigned a regular date at all, in tradition, points to its importance to the people who have lived and worked within earshot of red deer for centuries. Hillwalkers will of course be familiar with Meall a’ Bhuiridh, high above Rannoch Moor, which translates as hill of the roaring, or bellowing.
Fundamentally though, the reason for the rut’s reliability within a fixed timeframe is the photoperiod i.e. natural light levels. Shortening days trigger the physiological changes in red deer that underpin the rut, and while the weather and environment can vary from day to day, the levels of light throughout the year are fixed like clockwork.
During the summer, when light levels are high, testosterone levels in the stags are kept low. This allows the stags to tolerate one another’s presence, and you’ll often see stags grazing and congregating in loose social groups during those warmer months. But as the testosterone levels rise, that tolerance breaks down and the stags head off by themselves.
At the same time, their necks will have thickened considerably, on which they grow shaggy manes. This has the effect of making them look rather front-heavy, but the increased bulk in the neck also helps to make their roar louder. The larynx in a stag already occupies a position low down in their neck, but it is retracted even lower for the roar. This elongates their vocal tracts to make the roar deeper and larger-sounding.
And what a sound it is!
I don’t know if it’s because we’re so far removed from big scary animals these days, but there’s no denying that the sound of something that is clearly big, strong and wild close by, demands our attention. Such sounds affect us in very basic, emotional ways. Especially if, as is usually the case, the source of the sounds are unseen.
I can well imagine if you’re camping in the Highlands for the first time and you’ve a) never heard a stag before and b) have no idea about the rut, then you could be seriously unsettled by that sound booming out of the darkness.
“What the <bleep> was that!?”, has probably been uttered many times in such circumstances.
A still November night in 2010, camping on the summit of Gleouraich, is still among my most memorable camping experiences. A complex hill, its summit is within potential earshot of at least five coires, each of which was acting like an amplifier for whatever stags were occupying them. Unbeknownst to me at the time, Gleouraich translates as ‘The Roaring’, and fittingly there was roaring all night, from around me and below me. Coupled with ghostly mist creeping up the glens far below, the scene that night felt weirdly timeless.
The landscape certainly feels that much bigger, wilder and older when rutting stags are filling it with their roars. So far as wildlife experiences on these isles go, it’s way up there, and I certainly encounter lots of visitors to the Cairngorms who are desperate to experience it. But while the roars are especially stirring to us, they are intended for two principle non-human audiences.
Other stags, of course. The roar announces the stag’s presence, his dominance (or lack thereof), and acts as a means of sizing one another up over large distances. But it is also important to the hinds (the females), for the roar conveys information about a stag’s suitability as a mate.
I’d always assumed that a deeper roar, indicating a bigger and presumably more impressive stag, would be more attractive to the females. But I found at least one study online where stag roars were played through speakers to a population of hinds, and they found a preference among mating-ready hinds to medium-pitched stags rather than the Barry Whites of the red deer world. And interestingly, while some studies have found that rival stags react more aggressively and inquisitively to a low-pitched roar, others have found no difference whatsoever.
One thing is certain though. For we humans, a low roar suggests a bigger animal and, in my experience at least, inspires my awe more readily. I certainly take more notice when the nearby roar sounds BIG! It always amazes me though, how difficult it is to gauge distance when I hear it. Obviously, it depends on which way the wind is blowing, but the sound can travel a very long way – a couple of miles or more in favourable conditions.
By the time the roaring is filling the landscape, the hinds have congregated on the nutritious, energy-laden grasslands lower down the hillsides and in the bottom of the glens. These are the places stags seek out when their social groups break down.
The hinds undergo changes too as a response to the diminishing photoperiod. They don’t display the same external changes as the stags, but they become sexually receptive as the rut approaches, to coincide with the increasing testosterone in the males.
Hinds tend to breed for the first time in their second or third year, and while stags are able to mate within their first couple of years, their ability to do so is governed by more than just capability. They need to win the right to do so, and they can’t do this if they can’t present the absolute best version of themselves. i.e., a large, healthy stag with a fine, full pair of antlers. And crucially, this takes a few years.
Antlers begin their life as a fast-growing mix of cartilage, nerves and other tissues. They grow from the tip rather than the base, and start from the two permanent bony protrusions on a young male’s head, called pedicles. The soft, protective ‘velvet’ that initially coats the antlers provides a blood supply for the rapid growth, which can be as much as in inch per day in optimum conditions. During this growth phase the antlers are soft and can be damaged, and will even bleed, which can lead to deformities or asymmetric shapes. But eventually, as the testosterone levels increase when the rut approaches, the blood supply to the antlers is cut off, the velvet is shed, and the antlers quickly harden into bone.
Antlers are shed every spring when testosterone levels fall. This means a stag goes into each rut with a fresh pair, which can be advantageous if their old antlers were damaged during the previous year’s growth or during last autumn’s rut.
A young male won’t develop antlers in his first summer, but in his second he develops a small, single-pointed pair. Then, from his third year onwards these will grow larger and more complex, developing more branches and points (or tines) as they mature. However, while larger antlers do generally indicate an older stag, the number of points doesn’t accurately signify a stag’s age in years.
Nevertheless, in sporting terminology a Royal stag has 12 points, an Imperial has 14, and a Monarch has 16. But don’t be fooled by Edwin Landseer’s famous painting of the Monarch of the Glen, for his Monarch isn’t technically a Monarch at all. His stag’s antlers only have 12 points, which makes him a Royal.
Anyway, while it will take a few years for a young stag to look the part, this doesn’t suppress their urge to mate or fight. It is not uncommon to see younger stags, who have no real chance of mating this year, sparring with one another, but hinds are also discerning and won’t accept simply any challenger. They’ve been observed shunning very young males, running away from their advances.
Optimum breeding success in the rut tends to occur when stags are between five and eight years old. It takes this long for their antlers to grow large enough to be both imposing to larger males, and attractive enough to females.
When a stag finds a group of hinds (known as a harem), he will attempt to hold and defend it from challengers, and mate with as many hinds as possible. However, this isn’t something he can just do when he chooses. Hinds need to reach an optimum body weight to be able to successfully calf, and this can take a few years.
Stags must then wait for the hinds to come into oestrus (or ‘on heat’ as we might otherwise know it). Oestrus lasts anything from just a few hours to 24 hours, and will reoccur every 18 days unless mating is successful. During these short periods of receptiveness, hinds release pheromones that communicate their readiness to mate. A gland in the stag’s mouth (called the Jacobson’s Organ) enables him to smell these pheromones, and you might therefore have seen a stag with its top lip curled up, sniffing the air, or following a hind around with his tongue hanging out.
But while finding nice green grazing with plenty of hinds is one thing, holding it long enough to be able to mate is something else entirely. Harems of hinds can number just a few individuals, to many dozens. Clearly, the higher the number, the harder it is to defend against challenges, and this problem is compounded by the fact that a harem is not a single, unbreakable, permanent group. I’ve watched hinds freely wandering from one group to another, typically with an irate stag in tow, who unwittingly then leaves his harem unguarded and thus exposes himself to swift challenges.
Ultimately, stags cannot be everywhere at once, and so they are unlikely to hold a harem for the full duration of the rut. Power shifts over that time, passing from one individual to another, and each winning stag will attempt to mate with the receptive hinds.
To assert himself to hinds and stags alike, a stag will wallow and urinate in mud, indulging in scent-marking and thrashing his antlers in the bracken and grass. Bits of vegetation get caught on the antlers, and this helps to make the stags look more intimidating or impressive.
It’s certainly a spectacle that rewards being close enough to see finer details such as these through a pair of binoculars, but it’s equally impressive to watch the whole scene from a distance, from a lofty viewpoint, where you can see the massive game at play.
The striking thing when you watch it from afar, is just how constant the defence has to be. A stag with a harem is ever vigilant and cannot let his guard down for even a moment. He patrols constantly and roars often, attempting to assert himself.
Stags can run at more than 30mph and will readily do so to chase off erstwhile challengers, or herd the hinds if they get lured away to other groups. Such speed is all the more impressive when you consider the weight of those antlers. Can you imagine running with ten unwieldy ten kilograms on your head?
For smaller or weaker stags, the roar of a larger stag can be enough to deter them from attempting a challenge, long before they even get close enough to see them. If, however, a challenger discerns from the roaring that they might stand a chance at unseating a big stag, they will get much closer so that both stags can visually size one another up. To this end, they might parallel walk alongside one another at close quarters. If, after all that, the challenger still fancies his chances, then the two will lock antlers and attempt to physically defeat the other.
Physical fighting is high risk for both, so is not entered into lightly and is very much the last resort. As a result, much as they might capture our imaginations, physical confrontations aren’t as common as you might think. Injuries can and do happen, but mortal injuries are rare. But even then, another challenger lurking in the wings can be more tactical, waiting for a harem-holding stag to be overthrown before immediately challenging the new holder, who they sense is fatigued from a fight.
It’s a dynamic state of affairs where the fortunes of any one stag can quickly change for better or worse, either by their own actions or the actions of others. The reward of all this of course, is passing their genes on to the next generation. The cost, on the other hand, is the utter exhaustion that comes from the physical toll of it all.
Everything about the rut is energy-sapping, from the roaring to the running to the watching. There’s little time to eat, or at least not enough time to replace what energy the stags are losing. A stag who spends the rut actively challenging and defending should expect to lose between 20 and 30% of their pre-rut weight.
During last year’s rut, I watched over the course of a couple of weeks as the stag holding the hinds near my house clearly grew more fatigued as time wore on. I’d often see him standing still, head slightly drooped, eyes closed, the toil of the task clearly being felt. But as was the case for him just a day later, if you snooze you lose!
And then…..it’s over. The roars become fewer and further between, and the stags become noticeably social again. It’s always a strange sight, to see large stags once again lazing about with one another after such a brutally exhausting period of confrontation.
After the rut, the deer must endure the Scottish winter. If the rut has been protracted, and the stags have been left in poor condition, this can hamper their ability to grow thick winter coats, which can be life-threatening if winter is severe.
Antlers are retained through the winter, until the increasing photoperiod in spring triggers their casting via a clean break at their pedicles. It’s always tickled me to picture a stag stopping-up suddenly, or jumping, only for their antlers to fall off. Just imagine a) the surprise of the stag and b) the massive feeling of lightness that must accompany it. It must be like when you go to lift something and it’s much lighter than you’re expecting.
Casting antlers quite literally gets the physical weight of the rut and the harsh winter months off the stags’ heads. As for the hinds, their toll from the rut is only just beginning. If they survive the winter, their calves are born approximately eight months after the rut, in late May to June, at which point the stags will already re-growing their antlers for the next one.
What a life!
