Exploratory behaviour in shrews: fast-lived Sorex versus slow-lived Crocidura

Exploration of the environment is a key behaviour in animals. The exploratory behaviour of species or populations depends on different aspects of their ecology. New evidence suggests that differences in exploratory behaviour might also be related to life history strategies, with fast-lived animals (high metabolic rate, short life span) being faster explorers than slow-lived ones. We tested this assumption in shrews. Shrews are divided into two phylogenetic groups, which differ tremendously in life history. We compared the exploratory behaviour of three species, covering both phylogenetic groups. Shrews of the fast-lived genus Sorex were quicker to start exploration and to locate the first food patch. They also moved faster than the slow-lived genus Crocidura. Unlike many studies on exploratory behaviour that analyse only a short period of time (i.e. a single exploration bout with a fixed duration), we analysed the species-specific allocation of prolonged total exploration time into exploration bouts. Using this method, we could show that Sorex performed more, but shorter exploration bouts than Crocidura. Our results support the hypothesis of exploratory behaviour being related to life history. While the species we tested occur sympatrically, the two genera differ strongly in the climatic zones they inhabit. It is likely that also during evolution they faced different types of habitat and thus different selection pressures. These differences in evolutionary histories possibly favoured the evolution of their diversified life histories and exploration strategies.