Burrow sharing in the desert-adapted torch-tail spiny rat, Trinomys yonenagae

Among fossorial rodents burrow sharing is an important behavioral attribute that provides the foundation for multiple aspects of social structure. Within the family Echimyidae the torch-tail spiny rat (Trinomys yonenagae) is distinguished from closely related taxa by its tendency to live in burrows in desert habitats. Preliminary field studies have suggested that burrow systems of this species are shared by multiple adults. To test this hypothesis we used livetrapping and radiotelemetry to quantify patterns of burrow use in a population of torch-tail spiny rats located near Ibiraba, Bahia State, Brazil. Examination of our data indicates that 76.2% of 67 burrow systems monitored were occupied by > 1 adult, including same-sex pairs, male female pairs, and multiple adults of both sexes. Spatial overlap among adults captured in the same cluster of burrow entrances was extensive (72.0% +/- 27.0% based on 95% minimum convex polygons), with 66.7% of animals resident in the same burrow system using the same putative nest site. Collectively, examination of these data indicates that adult T. yonenagae share burrows and thus may be social. To place our findings in a comparative context and identify potential ecological correlates of burrow sharing in T. yonenagae we contrast our findings with data on space use by other fossorial, desert-dwelling rodents.