BUSCADOR RECOLECTA

Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/194623

Hibernation has been selected for increasing survival in harsh climatic environments. Seasonal variability in temperature may push body temperature of hibernating animals across boundaries of alternative states between euthermic temperature and torpor temperature, typical of either hibernation or summer dormancy. Nowadays, wearable electronics open a promising avenue to analyse the dynamics of criticality of physiological systems, such as body temperature fluctuating between activity and hibernation. We deployed temperature loggers to two hibernating edible dormice during a whole year under Mediterranean mild climate. Highly stochastic dynamical body temperatures with sudden switches allowed us to assess the occurrence of leading indicators of tipping points when approaching a critical transition. Hibernation dynamics showed flickering, which signalled the emergence of alternative attractors. More particularly, body temperature shifted between the alternative states far from the separating bifurcation points, which indicated the existence of long transients in hibernation dynamics. Flickering increased when body temperatures approached bifurcations. Gradual changes in air temperature drove saddle-node bifurcations in body temperatures between activity and hibernation, and the system showed hysteresis. Most metric- and model-based indicators anticipated critical transitions. For hibernating animals, hysteresis may increase resilience to end hibernation earlier than the optimal time, which may occur in regions where temperatures are sharply rising, especially during winter. Temporal changes in early indicators of critical transitions in hibernation dynamics may help to understand the effects of climate on evolutionary life histories and the plasticity of hibernating organisms to cope with shortened hibernation due to global warming., Peer reviewed