The Alpine Marmot Project

Welcome to the Alpine Marmot Project

Aurélie Cohas


Assistant Professor


tel. : +33(0)4 72 44 85 83
fax : +33(0)4 72 43 13 88

Biométrie et Biologie Évolutive
UCB Lyon 1 – Bât. Grégor Mendel
43 bd du 11 novembre 1918
69622 VILLEURBANNE cedex


My research focuses on the interface between behavioural ecology, evolutionary biology, genetics and population dynamics. For this, I combine behavioural observations, molecular tools and long-term data with the main biological model, the Alpine marmot, Marmota marmota.

Evolution of mating systems

Why do some individuals live in couples, while others choose multiple genetic and social partners (partner change, extra-pair paternity)? Based on what criteria do individuals choose their social partner(s) and genetic partner(s)? How are these criteria evaluated? What are the costs and benefits of these choices at the individual level? What are the consequences for population genetic structure or population dynamics?

perruche manchot empereur fou à pied bleu dik dik loup d'Ethiopie

In this context, my main research project currently focuses on partner choice for different genetic characteristics and the impact of choice on genetics and population dynamics. I am particularly interested in the consequences of mate choice for the evolution of genetic characteristics under selection, in particular on the evolution of major histocompatibility complex (MHC). This project builds on exceptional data, collected since 1990, on the population of Grande Sassière marmots; but also on data collected on different populations in the Alps and Pyrenees and during different time scales (contemporary, historical but also geological). It will quantify the role of mate choice in maintaining and promoting genetic diversity.

Evolution of sociality

Why do some individuals live alone while others live in complex social groups? Why do some become dominant while others remain subordinate? What are the costs and benefits of being dominant? What are the costs and benefits of being subordinate? What are the consequences of the size or composition of social groups? What are the consequences for the population genetic structure or population dynamics?

meerkat chimpanze chien de prairie abeille

In this context, I am currently interested in the consequences of the size and composition of social groups (1) on survival and reproductive success, and (2) on patterns of senescence in individuals who make up these groups. This project is based on both interspecific analysis of the mammals and on data from the population of Grande Sassière marmots. The Alpine marmot presents, in effect, a characteristic both fascinating and confusing: cooperative breeding. The Alpine marmot is thus characterized by the existence of social groups in which only the dominant pair reproduces, assisted by subordinates. These subordinates, although sexually mature are reproductively suppressed. They delay dispersion and instead help dominant individuals to raise their offspring. Such a social structure is expected to have important consequences for the life history traits, genetics and dynamics of the population.

Post-copulatory sexual selection

Why do some males develop extravagant secondary sexual characteristics (colours, weapons …)? Why do males develop some extravagant reproductive structures (disproportionate testicles, giant sperm …)? Do trade-offs exist between these traits? Do these traits coevolve with those of females? What are the roles of male competition and female choice in the evolution of these traits?

cerfs mandrilles ova spermatozoides

Sexual selection acts on secondary sexual characteristics such as the characteristics of the gametes and reproductive systems of males and females. I am currently interested in the potential trade-offs between these different traits and factors that can influence these trade-offs such as the mating system or mating tactics. For this, I am particularly interested in rodents and ungulates on which both interspecific and intraspecific studies are conducted (in collaboration with ONCFS for the work on ungulates).

Climate change

How does climate change affect the survival and reproduction of individuals? What are the consequences for population dynamics? Which physiological and behavioural mechanisms at the individual level can explain the observed changes at the population level? What are the evolutionary processes involved in the response of species to climate change?

corail manchot empereur fou à pied bleu ours glacier glacier

Recent climate changes on Earth have consequences for the distribution, size and performance of many animal populations. Understanding the repercussions of climate change is essential if we want to predict outcomes for these animal populations. While many studies in birds have shown changes in species’ phenology, such as earlier breeding seasons, the examples of mammals are quite rare. In the context of this project, I am interested in determining how and what climatic factors affect different life history traits in the Alpine marmot.



Berger V., Lemaître JF., Dupont P., Allainé D., Gaillard JM. and Cohas A. (2016) Age-specific survival in the socially monogamous alpine marmot (Marmota marmota): evidence of senescence. Journal of Mammalogy, XX: 1-9. pdf

Bichet C., Sauzet S., Averty L., Dupont P., Ferrandiz-Rovira M., Ferrari C., Figueroa I., Tafani M., Rézouki C., López BC., and Cohas, A. (2016) Multiple geographic origins and high genetic differentiation of the Alpine marmots reintroduced in the Pyrenees. Conservation Genetics, 17: 1157–1169. pdf

Berger V., Lemaître JF., Allainé D., Gaillard JM. and Cohas A. (2015) Early and adult social environments have independent effects on individual fitness in a social vertebrate. Proceedings of Royal Society B, 282:20151167 pdf

Berger V., Lemaître JF., Gaillard JM. and Cohas A. (2015) How do animals optimize the size-number trade-off when aging? Insights from reproductive senescence patterns in marmots. Ecology, 96:46-53 pdf

Ferrandiz-Rovira M., Lemaître J-F., Lardy S., López B.C., Cohas A. (2014) Do pre- and post-copulatory sexually selected traits covary in large herbivores? BMC Evolutionary Biology, 14: 1-9. pdf

Lardy S., Allainé D. and Cohas A. (2013) Intrasexual competition and female dominance tenure in a singular breeding mammal, the Alpine marmot. Animal Behaviour, 86:1155–1163. pdf

Tafani M., Cohas A., Bonenfant C., Gaillard J.-M., Allainé D. (2013) Decreasing litter size of marmots over time: a life-history response to climate change? Ecology, 94:580–586. pdf

Tafani M., Cohas A., Bonenfant C., Gaillard J.-M., Lardy S., Allainé D. (2013) Sex-specific senescence in body mass of a monogamous and monomorphic mammal: the case of Alpine marmots. Oecologia, 172:427–436. pdf

Kuduk K., Johanet A., Allainé D., Cohas A., Radwan J. (2012) Contrasting patterns of selection acting on MHC class I and class II DRB genes inthe Alpine marmot (Marmota marmota). Journal of Evolutionary Biology, 25: 1686-1693. pdf. supporting information

Lardy S., Cohas A., Desouhant E., Tafani M., Allainé D. (2012) Paternity and dominance loss in male breeders : the cost of helpers in a cooperatively breeding mammal. PLoS One 7: e29508. doi:10.1371/journal.pone.0029508. pdf

Lardy S., Cohas A., Figueroa I., Allainé D. (2011) Mate change in a socially monogamous mammal: evidences support the “forced divorce” hypothesis. Behavioural Ecology, 22: 120-125. pdf

Cohas A., Allainé D. (2009) Social structure influences extra-pair paternity in socially monogamous mammals. Biology Letters, 5: 313-316. pdf

Cohas A., Bonenfant C., Kempenaers B., Allainé D. (2009) Age-specific effect of heterozygosity on survival in alpine marmots, Marmota marmota. Molecular Ecology 18: 1491-1503. pdf

Cohas A., Yoccoz N.G., Bonenfant C., Goossens B., Genton C., Galan M., Kempenaers B., Allainé D. (2008) The genetic similarity between pair members influences the frequency of extrapair paternity in alpine marmots. Animal Behaviour, 76: 87-95. pdf

Cohas A., Yoccoz N.G., Allainé D. (2007) Extra-pair paternity in alpine marmot (Marmota marmota): Genetic quality and genetic diversity effects. Behavioral Ecology and Sociobiology, 61: 1081-1092. pdf

Cohas A., Bonenfant C., Allainé D., Gaillard J-M. (2007) Are extra-pair young better than within-pair young? A comparison of survival and dominance in alpine marmot. Journal of Animal Ecology, 76: 771-781. pdf

Cohas A., Yoccoz N.G., Da Silva A., Goossens B., Allainé D. (2006) Extra-pair paternity in the monogamous alpine marmot (Marmota marmota): The roles of social setting and female mate choice. Behavioral Ecology and Sociobiology 55: 597-605. pdf

Da Silva A., Luikart G., Yoccoz N.G., Cohas A., Allainé D. (2006) Heterozygosity-Fitness-Correlation revealed by microsatellite analyses in European alpine marmots (Marmota marmota). Conservation Genetics, 7: 371-382. pdf

Joly P., Morand , Cohas A.(2003) Habitat fragmentation and amphibian conservation: Building a tool for assessing landscape matrix connectivity. Comptes Rendus Biologie, 326: 132-139. pdf


Lardy S, Cohas A, Allainé D. (2011) The cost of helpers in cooperative breeders: mechanism and consequences of male-male competition in a cooperatively breeding mammal. ESEB, 13th congress, Tübingen, Germany. pdf

Lardy S, Cohas A, Allainé D. (2009) Divorce in a monogamous mammal, evidences supporting the “forced divorce” hypothesis. ESEB, 12th congress, Turin. pdf


Cohas A. (2006) Causes évolutives des paternités hors-couple chez les espèces socialement monogames: L’exemple de la marmotte alpine (Marmota marmota). [Evolutionary causes of extra-pair paternity in socially monogamous species: the example of the Alpine marmot (Marmota marmota)]. Thèse de doctorat. Université Claude Bernard Lyon 1, Lyon. pdf


Dupuis F. (2013) ALPES NATURE : Vanoise, objectif marmotte !  Alpes Magazine, n°142. pdf

Milleret R. (2013) . Dans le terrier des marmottes à La Grande Sassière. Le Dauphiné Libéré, 21 Juillet 2013.

Giraud M. (2009) Darwin c’est tout bête ! eds Robert Laffont.

Boone D. (2009) Rencontres au sommet. Version Femina n°384.

Kaplan M. (2007) Ain’t misbehaving. The Economist, 28 June 2007. pdf

Comby G. (2007) Comme pour les marmotte, l’adultère est-il salutaire? Le Matin Dimanche, 5 August 2007. pdf