Data from: Ancient DNA reveals differences in behaviour and sociality between brown bears and extinct cave bears

Ancient DNA studies have revolutionized the study of extinct species and
populations, providing insights on phylogeny, phylogeography, admixture
and demographic history. However, inferences on behaviour and sociality
have been far less frequent. Here, we investigate the complete
mitochondrial genomes of extinct Late Pleistocene cave bears and middle
Holocene brown bears that each inhabited multiple geographically proximate
caves in northern Spain. In cave bears, we find that, although most caves
were occupied simultaneously, each cave almost exclusively contains a
unique lineage of closely related haplotypes. This remarkable pattern
suggests extreme fidelity to their birth site in cave bears, best
described as homing behaviour, and that cave bears formed stable maternal
social groups at least for hibernation. In contrast, brown bears do not
show any strong association of mitochondrial lineage and cave, suggesting
that these two closely related species differed in aspects of their
behaviour and sociality. This difference is likely to have contributed to
cave bear extinction, which occurred at a time in which competition for
caves between bears and humans was likely intense and the ability to
rapidly colonize new hibernation sites would have been crucial for the
survival of a species so dependent on caves for hibernation as cave bears.
Our study demonstrates the potential of ancient DNA to uncover patterns of
behaviour and sociality in ancient species and populations, even those
that went extinct many tens of thousands of years ago.