Crowned leaders of the herd

It is autumn, and the trees in a country park are rapidly dropping their leaves. Those clinging to the branches are shades of red and amber; their fallen neighbours blanketing the ground below. In a clearing, two magnificent stags approach one another warily; more so, the challenging male, who is here to wrestle supremacy from the incumbent. As they advance, each utters a loud, deep roar. This is the height of the annual red deer rut, and the event is in full swing. Often the challenger will simply back off, having sized up his chances and realised he will not be victorious. But when the two animals are evenly matched, the physical battle begins. Time and again, the rivals clash together, locking their huge antlers momentarily before pulling apart and starting again. Meanwhile, the other males, and more importantly the females, who will mate with the eventual winner, stand on the sidelines, simply watching and waiting for the conflict to be resolved. Antlers are only found in the deer family, Cervidae. There are almost 100 living species, only one of which, the Chinese water deer, does not have antlers at all, preferring to rely on its sharp tusks. In almost all cases, antlers are confined to males, though female reindeer do have small antlers, which they use to clear away snow when searching for food.

Show of strength

Antlers vary hugely in size from species to species, the largest being those of the fallow deer and reindeer. They also vary considerably in shape and complexity,

some being flat, or palmate, and others simple spikes. Deer antlers are effectively an extension of the animal’s skull and are made from the same substance as their bones. They may look large and heavy, but they are very light and make up only a small fraction of the animal’s overall weight, usually less than one per cent. They are, however, very flexible and strong. When antlers first emerge, they are soft and pliable, and known as velvet antlers, because of their soft covering and texture. The ‘velvet’ has a crucial function, carrying blood packed with oxygen and the nutrients needed for the antlers to grow. They grow at an astonishing speed: up to 1in (2.5cm) a day, much faster than any other bone. They grow from the tip; initially as cartilage, only later hardening into bone. Antlers have one main function: to help decide which male deer will get to mate with a harem of females. Hence the annual rut, during which the males use their antlers not only for fighting, but also to display superiority to the watching females. Once the antlers have fully emerged, which can take up to three months, the blood vessels at their base are shut off, allowing them to harden. This process is repeated every year, with old antlers being shed and new ones growing, in a constant cycle. It used to be thought that when deer rub their antlers on trees, they are removing the velvet. In fact, that is only part of the reason: they also rub trees to mark them with their scent. Just six species of deer live in the wild in Britain. Of these, only two are native: the red and roe deer. And it is the red deer that has the largest and most impressive antlers. It also has the most spectacular rut, which takes place each autumn when the females come into oestrus, meaning they are fertile. Although the clashing of antlers may look highly dangerous, there is method in the ritual. Red deer antlers are forked, and these smaller protuberances, or tines, allow one male’s antlers to lock into place with those of his opponent. This means that they are able to clash their antlers together powerfully and frequently,

“But ere the branching horns could reach, That object of ill-founded ire, Sounds of resistless magic teach Submission to the savage sire” William Hayley, ‘The Stag’

with less chance of causing harm. Even so, injuries can occur and, in extreme cases, fights may even be fatal.

Growth and spread

Red deer males begin to grow their antlers in the spring, when there is plenty of food available to provide the energy they need for this arduous and energy-consuming task. Young males grow their first set of antlers in their first year, at just 10 months old, though they will not take part in the rut until they are more mature. With each passing year, they grow a larger and more complex set of antlers, enabling them to gradually progress up the hierarchy. Sometimes, however, they may not have to wait. Towards the end of each year’s rut, when the dominant males have retired, exhausted, younger males occasionally get the chance to mate with any females coming late into oestrus. The process of antler growth is governed by changes in day length in the spring, which trigger the higher levels of testosterone needed for breeding. This annual cycle is followed by species of deer in temperate and Arctic regions, though in tropical regions, such as India, sambar deer may shed and regrow antlers throughout the year. Usually a set of antlers will grow to a length of approximately 28in (70cm), yet they normally weigh just 2lbs 5oz (1kg). A typical stag weighs between 350-530lb (160 -240kg). However, antlers can grow much bigger; up to 45in (115cm) long and weighing as much as 11lb (5kg). As the stag matures, his antlers may also become more complex, with more ‘points’. These mature stags are much valued by deerstalkers, who have their own terminology to describe the mature males. A male with 12 points,

six per antler, is called a royal stag; one with 14 points is an imperial stag, and rare examples with 16 points or more are known as monarchs. One stag found on Exmoor had 17 points on his antlers.

Sign of health

A deer’s antlers are one of the most obvious examples in nature of what are referred to as secondary sexual characteristics, another being the peacock’s ornate tail. In effect, they have no practical use, apart from enabling a stag to attract a group of females, and so reproduce. Growing large and impressive antlers is crucial, as their size and weight decide the male’s position in the social hierarchy of the herd and so increase his chances of passing on his genes to the next generation. Studies have also shown that the stags with the largest antlers, relative to their size and weight, are indeed healthier. They are able to put more energy into antler growth and are more resistant to disease than others. But having large antlers may also come at a price. During the rut, the dominant stags will not feed and can become exhausted through a lack of nutrition and the constant demands of seeing off rivals. A large set of antlers may also mean that the stag is less likely to survive a hard winter, having used so much energy to grow them. This may explain why, over time, the average size of antlers in a herd does not appear to increase, as might be expected, given the pressures of sexual selection. Oddly, considering antlers are not needed once the rut is over, stags retain their set until late winter, usually shedding them in March or April, in time to regrow a new set. The annual rut is the only time when male and female red deer roam together. The rest of the year, they usually live in single-sex herds, though mixed-sex groups can be found in parts of the Scottish Highlands. After the rut, they return to their separate existence, the female giving birth approximately eight months later, from mid May to mid July. Soon afterwards, the cycle begins again, and the spectacle of the autumn rut is played out once more.

In Britain, the fallow deer, Dama dama, is distinguished by its palmate antlers. It is most commonly seen in England and Wales.

The velvety surface of a young stag’s antlers. Highly vascular, this furry skin supplies the growing bone with oxygen and necessary nutrients.

A red deer after its antlers have dropped, usually once winter is over. Each new antler grows from an attachment point called a pedicle.

Antlers grow from the tip and are initially cartilage, to be replaced by bone tissue as they develop.

A stag sheds velvet from its antlers in autumn, once they are fully formed. The bone then dies, to become what is known as a mature antler.

The red deer’s antlers grow at almost a 90 degree angle from the brow, an important identification characteristic.

A fallen roe deer antler. Unlike those of the red deer, they usually fall in November. If a deer dies when it has antlers, they are almost impossible to break off, remaining stuck to the skull bone.