Reproductive aspects of female Andean bears (Tremarctos ornatus) in the Chingaza massif, eastern range of the Colombian Andes

Abstract

Knowledge of reproduction in wild Andean bears (Tremarctos ornatus) is scarce. Here we provide novel information about litter size, birth timings, courtship and multi-generational groups in a population in the Chingaza massif in Colombia. Pregnant females, mothers with cubs, estimated birth times, and litter size were registered through camera trapping of a population at the Chingaza massif (Colombia) between 2011 and 2016. A total of 34 independent records of reproductive female bears were obtained. Twenty-eight (28) different reproductive females were recognized by external key features. Six different females were recorded only pregnant, two others were recorded pregnant and later with cubs, and 20 others were recorded only with cubs. In total, 29 cubs were recorded in 22 litters, with a mean litter size of 1.27 (SD = 0.45): 16 litters with one cub, 5 with 2 cubs, and 1 with 2 cubs + a big cub from a previous litter (>1 year). The highest records of mothers with little cubs were obtained for the low rain season in December, January, and February, full of dry-season-fruiting Ericaceae shrubs. Likewise, the highest estimated births were obtained during the rainy time in June. Multi-generational groups and the courtship behaviors are reported for the first time in Colombia.