Telomeres are emerging as a biomarker for ageing and survival, and are likely important in shaping life-history trade-offs. In particular, telomere length with which one starts in life has been linked to lifelong survival, suggesting that early telomere dynamics are somehow related to life-history trajectories. This result highlights the importance of determining the extent to which telomere length is inherited, as a crucial factor determining early life telomere length. Given the scarcity of species for...

A higher proportion of long-lived animals die from senescence than short-lived animals, yet many long-lived homeotherms show few signs of physiological aging in the wild. This may, however, differ in long-lived diving homeotherms that frequently encounter hypoxic conditions and have very high metabolic rates. To examine aging within a long-lived diving homeotherm, we studied resting metabolism and thyroid hormones (N = 43), blood oxygen stores (N = 93), and foraging behaviour (N = 230) of...

Animal ecology is shaped by energy costs, yet it is difficult to measure fine-scale energy expenditure in the wild. Because metabolism is often closely correlated with mechanical work, accelerometers have the potential to provide detailed information on energy expenditure of wild animals over fine temporal scales. Nonetheless, accelerometry needs to be validated on wild animals, especially across different locomotory modes. We merged data collected on 20 thick-billed murres (Uria lomvia) from miniature accelerometers with measurements...

Measuring the energy requirements of animals under natural conditions and determining how acquired energy is allocated to specific activities is a central theme in ecophysiology. Turtle reproductive output is fundamentally linked with their energy balance so a detailed understanding of marine turtle energy requirements during the different phases of their life cycle at sea is essential for their conservation. We used the non-invasive accelerometry technique to investigate the activity patterns and energy expenditure (EE) of...

A growing body of studies is showing that offspring telomere length (TL) can be influenced by the age of their parents. Such a relationship might be explained by variation in TL at conception (gamete effect) and/or by alteration of early growth conditions in species providing parental care. In a long-lived bird with bi-parental care, the Alpine swift (Apus melba), we exchanged an uneven number of 2 to 4-day-old nestlings between pairs as part of a...

Telomeres are protective DNA–protein complexes located at the ends of eukaryotic chromosomes, whose length has been shown to predict life-history parameters in various species. Although this suggests that telomere length is subject to natural selection, its evolutionary dynamics crucially depends on its heritability. Using pedigree data for a population of white-throated dippers (Cinclus cinclus), we test whether and how variation in early-life relative telomere length (RTL, measured as the number of telomeric repeats relative to...

The identification of sea turtle behaviours is a prerequisite to predicting the activities and time-budget of these animals in their natural habitat over long term. However, this is hampered by a lack of reliable methods that enable the detection and monitoring of certain key behaviours such as feeding. This study proposes a combined approach that automatically identifies the different behaviours of free-ranging sea turtles through the use of animal-borne multi-sensor recorders (accelerometer, gyroscope and time-depth...

Age at reproduction can influence the survival and future reproduction of an individual as well as that of their offspring. Remarkably, it has been shown that grandmaternal age at reproduction can also affect the characteristics of grandoffspring in humans and in laboratory or semi-captive animals. However, currently we do not know whether grandmaternal age effects exist in wild populations. We gathered data on female age at reproduction, offspring and grandoffspring characteristics using a 16-year long-term...

Within-group competition over food resources can be a major cost of social living. In the wild, foragers are confronted with social (e.g. hierarchical rank) and ecological (e.g. food availability and distribution) challenges that affect their foraging decisions and feeding success. Exhibiting prosocial behaviors, such as tolerance at feeding sites, can benefit group members by developing affiliative social relationships, enhancing access to resources and maximizing fitness. We examined social tolerance at feeding sites in Callithrix jacchus,...

Southern elephant seals (Mirounga leonina) are known to move and aggregate while moulting, but little is known about their behaviour on land during this time. In this study, 60 adult females were monitored (23 with GPS tags) during four moulting seasons, between 2012 and 2016 at Kerguelen Archipelago, Indian Ocean. Population surveys were recorded each year (N = 230 daily counts) and habitat use was analysed in relation to the stage of the moult and...

Three mechanisms have been proposed to underlie reciprocation of social behaviors in gregarious animals: ‘calculated reciprocity’, ‘emotional bookkeeping’ and ‘symmetry-based reciprocity’. Among these explanations, emotional book-keeping has received the broadest support from experimental and observational studies. On the other hand, three individual-based models have shown that reciprocation may emerge via ‘symmetry-based reciprocity’, ‘emotional bookkeeping’, or a combination of both mechanisms. Here we use these three models to assess their relative fit with empirical data on...

Global warming is causing profound modifications of aquatic ecosystems and one major outcome appears to be a decline in adult size of many fish species. Over the last decade, sardine populations in the Gulf of Lions (NW Mediterranean Sea) have shown severe declines in body size and condition as well as disappearance of the oldest individuals, which could not be related to overfishing, predation pressure, or epizootic diseases. In this study, we investigated whether this...