Lifespan in Bats: Enigmatic Longevity and Evolutionary Stasis

Abstract

Bats are known to live significantly longer than other mammals of similar body size - a fact that continue to puzzle researchers, as the underlying reasons behind bats extended lifespan remain poorly understood. Our study aims to identify key morphometric and life-history traits that contribute to extreme longevity of bats and to describe the evolutionary patterns of bat lifespan. Using phylogenetically informed regression with dummy variables and dataset of 108 bat species, we examined the effects of body length, body weight, forearm length, diet, reproduction rate, hibernation, and climatic preference on longevity. Our analysis revealed that lifespan in bats is influenced by their body size (the proxy for which is the forearm length), reproduction rate, some specific diets (hematophagy and omnivory), and climate, while other traits showed no noteworthy effects. Moreover, we fitted several likelihood models for the evolution of forearm length, body length, body mass and lifespan. All these traits best followed an Ornstein-Uhlenbeck model. As the result, lifespan appeared to be a highly constrained trait with an estimated evolutionary optimum of approximately 13.5 years across Chiroptera. These findings support the idea that longevity may have been present in ancestral bat lineages and is shaped by the combination of ecological and morphological factors.