Where are the sloths? The first population estimates for the brown-throated sloth (Bradypus variegatus) in an urban Atlantic Forest protected area

Estimates on demographic parameters altogether with social factors are integral and can be very useful to assess the risks that a population may face in the future. Rescue operations may provide a unique opportunity to gather data on individuals of an area and thus provide population information. Animal rescue data provided by the Rio de Janeiro Botanical Garden fauna team were used to understand the structure of a population of Bradypus variegatus in an urban remnant of the Atlantic Forest (Tijuca National Park, PNT). This study aimed to provide data on this population’s abundance, density estimation, sex ratio, and occurrence in the PNT. We rescued 44 sloths, four of whom were dead. The population density was estimated at 0.6 ind / ha, a low-density value compared to other urban remnants (8.5 to 12.5 ind / ha). Our model suggests some decline in recruitment but still a stable population with an increase in size. Although B. variegatus is not currently considered threatened due to their broad distribution, they can be locally extirpated due to population unfeasibility in forest remnants of Atlantic Forest regions, suggesting we should evaluate its threat levels at the population level.