Male badgers that spend their youth fighting tend to age more quickly than their passive counterparts according to new research from the University of Exeter.
The 35-year study revealed that male badgers living alongside a high density of other males grow old more quickly than those living with lower densities of males.
The results, which are published in the Proceedings of the Royal Society B, indicate that competition between males in early life accelerates ageing in later life, providing a potential explanation for why males age faster than females.
Author Christopher Beirne from the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall said: "The study shows that when male badgers don't have to fight for a mate, they can prioritise their health and wellbeing and as a result they age more slowly. However, when badgers fight a lot in their youth, they really pay for it by ageing rapidly in later life."
Unlike the males, female badgers appeared to be unaffected by the density of other females in the area, indicating that they don't suffer from the effects of competition in the same way as males.
Co-author Dr Andrew Young from the University of Exeter said: "The findings are particularly interesting because males age faster than females in many species, including our own, but we don't really understand why. Our findings suggest that male badgers age faster than females because of the male-male competition that they experience during their lifetimes; males that experience strong competition age more quickly than females, while males that experience little competition do not."
The exact causes of the observed ageing are not fully understood and so the findings provide rare support for the view that sex differences in ageing rates arise in part from reproductive competition and the costs associated with living alongside rivals.
Previous studies have shown that male badgers are more likely to have bite wounds, contest matings and have a higher mortality rate than females.
The researchers quantified ageing as the rate of body mass loss in late-life because badgers, like humans, become frail and lose weight as they grow old. Body mass in badgers, which can live for up to 13 years in the wild, is positively associated with reproductive success and survival, and so rapid declines in body mass are likely to indicate reduced reproductive success and survival prospects.
The research is the result of a collaboration between the University of Exeter and the Animal and Plant Health Agency's long-term field study in Gloucestershire, UK, where the resident European badger population has been continuously monitored since the 1970s.
Sex differences in senescence: the role of intra-sexual competition in early adulthood by Christopher Beirne, Richard Delahay, Andrew Young is published in Proceedings of the Royal Society B.
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About the University of Exeter
The University of Exeter is a Russell Group university and in the top one percent of institutions globally. It combines world-class research with very high levels of student satisfaction. Exeter has over 19,000 students and is ranked 7th in The Times and The Sunday Times Good University Guide league table, 10th in The Complete University Guide and 9th in the Guardian University Guide 2015. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was The Sunday Times University of the Year 2012-13.
The University has four campuses. The Streatham and St Luke's campuses are in Exeter and there are two campuses in Cornwall, Penryn and Truro. The 2014-2015 academic year marks the 10-year anniversary of the two Cornwall campuses. In a pioneering arrangement in the UK, the Penryn Campus is jointly owned and managed with Falmouth University. At the campus, University of Exeter students can study programmes in the following areas: Animal Behaviour, Conservation Biology and Ecology, English, Environmental Science, Evolutionary Biology, Geography, Geology, History, Human Sciences, Marine Biology, Mining and Minerals Engineering, Politics and International Relations, Renewable Energy and Zoology.
The University has invested strategically to deliver more than £350 million worth of new facilities across its campuses in the past few years; including landmark new student services centres - the Forum in Exeter and The Exchange at Penryn - together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. There are plans for another £330 million of investment between now and 2016.
About the University of Exeter's Centre for Ecology and Conservation (CEC)
Staff at the Centre for Ecology and Conservation, based on the Penryn Campus, undertake cutting-edge research that focusses on whole organism biology. The CEC has three interlinked research groups: Behaviour, Ecology and Conservation, and Evolution which constitute 40 academics and over 100 early career researchers. It engages widely with businesses, charities and government agencies and organisations in Cornwall, the Isles of Scilly and beyond to translate its research into societal impact. Staff at the CEC deliver educational programs to some 500 undergraduate and 100 postgraduate students.
A new £5.5 million Science and Engineering Research Support Facility (SERSF) is currently under construction at the Penryn Campus. The facility will bring pioneering business, science and engineering together and will provide space for the growing CEC alongside the University of Exeter Business School, which is expanding into Cornwall, and the University's Marine Renewables team.
The University of Exeter and Falmouth University are founding partners in the Combined Universities in Cornwall (CUC), a unique collaboration between six universities and colleges to promote regional economic regeneration through Higher Education, funded mainly by the European Union (Objective One and Convergence), the South West Regional Development Agency and the Higher Education Funding Council for England, with support from Cornwall Council.