Sloth biology: an update on their physiological ecology, behavior and role as vectors of arthropods and arboviruses

Abstract

This is a review of the research undertaken since 1971 on the behavior and physiological ecology of sloths. The animals exhibit numerous fascinating features. Sloth hair is extremely specialized for a wet tropical environment and contains symbiotic algae. Activity shows circadian and seasonal variation. Nutrients derived from the food, particularly in Bradypus, only barely match the requirements for energy expenditure. Sloths are hosts to a fascinating array of commensal and parasitic arthropods and are carriers of various arthropod-borne viruses. Sloths are known reservoirs of the flagellate protozoan which causes leishmaniasis in humans, and may also carry trypanosomes and the protozoan Pneumocystis carinii.

Modular mobile foundation species as reservoirs of biodiversity

“…One of the best cases has been made for murex snails in the Sea of Cortez (Prescott and Cudney-Bueno 2008), although their study did not quantify how diversity of epifauna on murex differed from the primary substrate, nor did it identify mechanisms of facilitation other than observed substrate provision. Other potential examples include mudsnails (Thomsen et al 2010), horseshoe crabs (Patil and Anil 2000), and decorator crabs (Wicksten 1980) that are commonly encrusted with algae and invertebrates and can be locally abundant, as well as sloths whose fur can be inhabited by a diverse community of algae and arthropods (Gilmore et al 2001). Many other previously unrecognized foundation species will be appreciated as such once their common characteristics are identified, and they are evaluated for their effects on diversity and potential for dispersing other organisms.…”

Oddities and Curiosities in the Algal World

“…The camouflage is crucial to the sloth's survival, because its inability to move quickly makes it an easy target for predators such as the harpy eagle (Harpia harpyja). Among the many odd features of these interesting animals, perhaps the oddest of all is their hair which, with its peculiar structure and its algal presence, is unlike the hair of any other mammal (Gilmore et al, 2001). During the dry season, the hair of sloths usually has a dirty brown coloration, but during long period of rain it may show a very appreciable greenish tinge brought about by the increased presence of symbiotic algae.…”

The Evolution of Cathemerality in Primates and Other Mammals: A Comparative and Chronoecological Approach

“…Callicebus ) might have favoured nocturnality in Aotus sp. Observations of daytime activity in A. azarai during the winter months in Paraguay [Wright 1989] led to speculation that the relaxation of Clarke et al, 1995;Winter, 1996. b Abenspergtraun and Deboer, 1992;Serena, 1994. c Gilmore et al, 2001. competition at higher latitudes in Argentina, Paraguay and Bolivia might result in activity rhythms that resemble cathemerality. However, Wright [1989] stressed that predation is probably more pivotal than competition, and the most recent long-term data on cathemeral Aotus populations in Argentina provide little or no support for correlations between cathemerality and interspecifi c competition [FernandezDuque, 2003, in press;Fernandez-Duque and Erkert, 2006].…”

“…[e.g. Chiarello, 1998;Gilmore et al, 2001]. Chiarello [1998] suggests that their ineffective control of body temperature is offset by increasing diurnal activity in colder regions and increasing nocturnal activity in warmer regions so that they can limit themselves to a narrower range of more favourable ambient temperatures.…”