Publications by authors named "Kay Welser"

Powerful digital grasping is essential for primates navigating arboreal environments and is often regarded as a defining characteristic of the order. However, data on primate grip strength are limited. In this study, we collected grasping data from the hands and feet of eleven strepsirrhine species to assess how ecomorphological variables-such as autopodial shape, laterality, body mass and locomotor mode-influence grasping performance.

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The dwarf lemurs (Cheirogaleus spp.) of Madagascar are the only obligate hibernators among primates. Despite century-old field accounts of seasonal lethargy, and more recent evidence of hibernation in the western fat-tailed dwarf lemur (Cheirogaleus medius), inducing hibernation in captivity remained elusive for decades.

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Feast-fast cycles allow animals to live in seasonal environments by promoting fat storage when food is plentiful and lipolysis when food is scarce. Fat-storing hibernators have mastered this cycle over a circannual schedule, by undergoing extreme fattening to stockpile fuel for the ensuing hibernation season. Insulin is intrinsic to carbohydrate and lipid metabolism and is central to regulating feast-fast cycles in mammalian hibernators.

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In nature, photoperiod signals environmental seasonality and is a strong selective "zeitgeber" that synchronizes biological rhythms. For animals facing seasonal environmental challenges and energetic bottlenecks, daily torpor and hibernation are two metabolic strategies that can save energy. In the wild, the dwarf lemurs of Madagascar are obligate hibernators, hibernating between 3 and 7 months a year.

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Manual grasping is widespread among tetrapods but is more prominent and dexterous in primates. Whether the selective pressures that drove the evolution of dexterous hand grasping involved the collection of fruit or predation on mobile insects remains an area of debate. One way to explore this question is to examine preferences for manual versus oral grasping of a moving object.

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The origin and evolution of manual grasping remain poorly understood. The ability to cling requires important grasping abilities and is essential to survive in species where the young are carried in the fur. A previous study has suggested that this behaviour could be a pre-adaptation for the evolution of fine manipulative skills.

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