Why are male antlers and horns so large?

Why are male ungulate antlers and horns so large? Darwin, when proposing his theory of evolution and sexual selection, suggested that the size of male ungulate antlers and horns may reflect male individual quality, and thereby be used by conspecifics as an honest signal of male sexual vigor, health, strength, hierarchical status, or ability to fight.

Researchers from five institutes in three European countries (CEFS-INRA, LBBE- CNRS , and ONCFS in France; Grimsö Wildlife Research Station in Sweden; and CEES in Norway) have investigated this issue for the first time in a territorial ungulate species, the European roe deer. In a paper published in the April issue of the American Naturalist, Cécile Vanpé and collaborators analyzed long-term data on antler size from three contrasting populations of roe deer (Bogesund in Sweden, and Chizé and Trois Fontaines in France).

They demonstrated that antler size in males is indeed an honest signal of their individual quality as assessed by age and body mass.

Jean-Michel Gaillard comments, "Our results provide evidence that antler size of male roe deer mainly reflects their age and body mass, and is more resilient to variation in environmental conditions such as climate, food resources, and density." "Body mass and age are both reliable descriptors of individual quality in most vertebrates and have been shown to affect the ability to fight and the dominance of males. Hence, by choosing their sexual partners on the basis of their large antlers, females may thus ensure that they mate with a high quality mate," says Cécile Vanpé.

Petter Kjellander adds, "Males may also use antler size of rival males as a cue to assess the possibility of winning a fight in order to control and monopolize more females for reproduction." Mark Hewison concludes, "This leads to the key question of whether males with larger antlers do have greater access to females than other males." According to François Klein, Guy Van Laere, and Daniel Delorme, this study clearly indicates that antler size might be used as an indicator of individual quality on which management rules could be based.

Citation: Cécile Vanpé, Jean-Michel Gaillard, Petter Kjellander, Atle Mysterud, Pauline Magnien, Daniel Delorme, Guy Van Laere, François Klein, Olof Liberg, and A. J. Mark Hewison, "Antler size provides a honest signal of male phenotypic quality in roe deer" The American Naturalist, volume 169 (2007), pages 481–493

Source: University of Chicago

Related stories:

The groan says it all -- dominant male deer have the deepest calls
(PhysOrg.com) -- The low timbre and enticing vibrations of a deep voice have long been considered a key element of male attractiveness. Now it seems that it's not just human females that appreciate a husky vocalisation.
Honest lovers? Fallow buck groans reveal their status and size during the rut
It is known that the phonic structure of calls produced by males during the breeding season may signal quality-related characteristics in many different types of animals. Previous research on mammals has mainly focussed on the relationship between the acoustic components of vocalizations and one aspect of male quality: body size.
Male painters exposed to fertility damaging chemicals
Men working as painters and decorators who are exposed to glycol ethers are more likely to have poor semen quality, according to research carried out by scientists from the Universities of Sheffield and Manchester.
You are what your mother eats: First evidence that mother's diet influences infant sex
New research by the Universities of Exeter and Oxford provides the first evidence that a child’s sex is associated with the mother’s diet. Published today, in the journal Proceedings of the Royal Society B: Biological Sciences, the study shows a clear link between higher energy intake around the time of conception and the birth of sons. The findings may help explain the falling birth-rate of boys in industrialised countries, including the UK and US.
Where do you stand? Research shows clues in rules of the wild
If you wonder where you stand in the social pecking order at work, home and in the community, a little known group of primates found only in the highlands of Ethiopia may offer some clues.
Why Do Males and Females Frequently Differ in Body Size and Structure?
As even the most casual observer of nature knows, males and females frequently differ in body size, form and structure. But how these differences have developed – a topic studied for decades by evolutionary biologists – is not as clear.
Influence of sex and handedness on brain is similar in capuchin monkeys and humans
Capuchin monkeys are playful, inquisitive primates known for their manual dexterity, complex social behavior, and cognitive abilities. New research now shows that just like humans, they display a fundamental sex difference in the organization of the brain, specifically in the corpus callosum, the region that connects the two cerebral lobes.
Why female deer like a stag to be a big noise in the forest
Impressive antlers may be the most eye-catching attribute of the male red deer, but it's the quality of a stag's mating call that attracts the female of the species, a new study from the University of Sussex, published today (Weds 6 June), has discovered.

News discussion:

General Science news