Spontaneous ingestion of water by a free-ranging maned sloth, Bradypus torquatus, in the Ibura National Forest, northeastern Brazil

Abstract

Abstract Water is an important limiting factor in the ecology of many animals, and even in rainforests, arboreal mammals, such as sloths, may have limited access to water sources. Here, we describe the spontaneous ingestion of water by a free-ranging three-toed sloth (Bradypus torquatus). The event occurred in the Ibura National Forest, in northeastern Brazil, where a sub-adult B. torquatus was monitored over three days in January, 2014. On the third day, the sloth was feeding on mature leaves and, at 16:22 h, it began raining heavily. Once the rain ceased, the sloth began to ingest the rainwater trickling down a vertical branch by licking it, and continued to ingest water for approximately 26 minutes. This behaviour indicates that the water was a valuable resource for this sloth, and sheds new light on the previous assumptions that these animals are able to satisfy their water requirements through their diet alone. This observation, together with an overview of the data on the ingestion of water by arboreal mammalian folivores, indicates that the direct ingestion of water may depend on specific local conditions, in particular, the availability of water sources, as well as the specific necessities of the mammal. As the lack of previous records of this behaviour in sloths is likely due to the cryptic behaviour of these animals, this finding highlights the importance of continuous, long-term behavioural monitoring for a more complete understanding of sloth ecology.