Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Complex sex life of goats could have implications for wildlife management

A new study of the mating habits of mountain goats reveals the vastly different strategies of males in different populations and could shed light on the unseen impacts of hunting.

A Durham University-led research team found that male chamois (a species of wild goat-antelope) adopt different strategies in different populations in order to succeed in the rut: some put a lot of energy in at a young age, while others wait until they are much older.

Researchers looking at neighbouring populations of chamois in Northern Italy found that males in one population delay their reproductive efforts until an older age when their size and experience allow them to dominate in the rut. They then put increasing effort into breeding until they die.

The study is the first to show clearly that this strategy of 'terminal investment', a pattern of higher reproductive effort in older age, is pursued by males in an animal population. The results, published in the journal PLoS One, show that reproductive strategies in animals are complex and can show surprising variation across neighbouring districts.

It's not clear why there is such variation but the way that these populations are managed through hunting could be a factor, according to the researchers. At present, 32 per cent of the hunting quota is made up of older males, even though these males make up only 23 per cent of the population.

If too many larger, older males are taken out of a population, younger males may be able to muscle in and start breeding. Years of rutting could exhaust these younger males, meaning that they are in poorer condition when they reach old age. If this reasoning is accurate, selectively hunting older males in populations such as this will have the effect of reducing the condition of older males in future.

This suggests that alternative hunting practices – such as hunting males in proportion to their age distribution – might be a better strategy.

Studies of bighorn sheep, a similarly hunted mountain species in America, have also suggested that selective hunting of older males can reduce genetic quality.

Researchers looked at three populations in detail and found that in neighbouring areas surprisingly different strategies prevailed; in one, the terminal investment strategy was dominant, in another, where older males were harvested at a slightly higher rate, the live fast/die younger strategy prevailed.

The group, led by Drs Stephen Willis and Philip Stephens, School of Biological and Biomedical Sciences, Durham University, in collaboration with ecologists at the University of Sassari, Italy, used data from 15,000 hunted male chamois, collected since 1973, to explore their breeding strategies. They looked at the amount of energy males of different ages expended during the annual rut at several sites in the Italian Alps and found unexpected variation across populations.

Co-author Dr Stephen Willis said: "It seems that chamois can have fun in their youth or enjoy their old age but they can't do both. In one valley, males left it until much later to get involved in the rut but, once involved, they showed a pattern of increasing effort, right up to the end of their lives."

The team was able to see how much energy was expended by rutting chamois by looking at how the body masses of males changed throughout the rut period. They were also able to establish the ages of shot individuals from the number of annual growth rings in their horns. The speed at which the animals lose body mass shows how much effort males put in to establishing and patrolling territories, and fighting to defend their harem.

At a site with more hunting and a 'faster' pace of life, the team found that male weight loss during the rut was high, that chamois began rutting at an earlier age and that life-expectancy was lower. By contrast, at a site with a 'slower' pace, lifespans were longer, the weight loss of males was less and males tended to increase the effort they put into reproduction as they got older.

Male chamois barely eat during the rut and use their non-rutting time for resting rather than foraging. They must put on weight prior to the rut in order to succeed and to survive the following winter months.

Co-author of the study, Tom Mason, a Durham University PhD student working on the project, said: "In most species, all males follow one or other of these strategies. It is intriguing that among chamois in different areas, males have different strategies, which might be related to resources, climate or competition."

Dr Philip Stephens added: "These patterns are consistent with two competing theories about how males should optimally allocate effort to reproduction during their lives, so you wouldn't normally expect to see them being displayed so differently by males in neighbouring populations of the same species."

The study is funded by the Natural Environment Research Council (NERC).

Carl Stiansen | EurekAlert!
Further information:

More articles from Studies and Analyses:

nachricht Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung

nachricht High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>