Choloepus hoffmanni, Peters, 1858

Russell A. Mittermeier & Don E. Wilson, 2018, Megalonychidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 104-117 : 116-117

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Hoffmann’s Two-toed Sloth

Choloepus hoffmanni

French: Paresseux de Hoffmann / German: Hoffmann-Zweifingerfaultier / Spanish: Perezoso didactilo de Hoffmann

Taxonomy. Choloepus hoffmanni Peters, 1858 ,

“Costa Rica.” Restricted by G. G. Goodwin in 1946 to “Escazu,” San José Province, Costa Rica. Corrected by R. M. Wetzel and F. D. de Avila-Pires in 1980 to “Costa Rica, Heredia, Volcan Barba.”

Choloepus hoffmanni occurs in two disjunct areas: northern (nominate hoffmanni , agustinus, and capitalis ) and southern ( juruanus and pallescens). A recent mtDNA analysis including three subspecies supported their differentiation and indicated deep divergence between lineages from northern ( hoffmanni ) and southern ( juruanus and pallescens) populations. Five subspecies recognized.

Subspecies and Distribution. C.h.hoffmanniPeters,1858—fromSHondurasSEtoNW&NColombia,WoftheAndes. C.h.agustinusJ.A.Allen,1913—fromNWVenezuelaSthroughCColombiatoNEcuador. C.h.capitalisJ.A.Allen,1913—SWColombiaandWEcuador. C.h.juruanusLLonnberg,1942—SWBrazilianAmazon(AmazonasandAcrestates),SEPeru,andNBolivia. C.h.pallescensLLonnberg,1928—extremeSColombia(PutumayoDepartment),EEcuador,andEPeru.DistributionofHoffmann’sTwo-toedSlothinBrazilisunclear,andfurthersurveysareneeded.TherearetwodoubtfuloutlyingrecordsfromnorthernMatoGrossoState,Brazil.TheselocalitiesarenearorwithindistributionofLinnaeus’sTwo-toedSloth( C.h. didactylus ), suggesting possible misidentification.

Descriptive notes. Head-body 500-700 mm, tail 14-30 mm, ear 15-37 mm, hindfoot 100-153 mm; weight 2.7-10 kg. There is no outward sexual dimorphism. Hoffmann’s Two-toed Sloths are medium-sized and arboreal; they have long foreand hindlimbs, nearly equal in length. Forelimbs have two large, curved claws, and hindlimbs have three. Front claws average 55-65 mm and hindclaws 50-65 mm. Teeth are rootless and ever-growing and lack enamel. Incisors are absent, and premolars are indistinguishable from molars. Adult pelage ranges from yellowish, blond, buff, or tan to light brown, butit can appear shaded pale green from algae that grows on hair. Facial hair is usually lighter than hair on rest of body. Cheek and throat hairs are distinctly shorter and finer than those on neck and shoulders. Dense undercoatis lacking; abdominal hair is parted in middle and flows toward mid-dorsum. Geographical variation occurs in color and length of hairs described for adult and young Hoffmann’s Two-toed Sloths from Colombia; young sloths can have golden and light honey or dark brown hair, depending on the specific geographical location. Diploid number is 2n = 50-51.

Habitat. Primary, secondary, lowland, and montane forests. Hoffmann’s Two-toed Sloths spend most of their time in canopies of continuous forests, dominated by mature and lush trees in rainforest, dry forests, and riparian forest ecosystems. They also occur in dry forest fragments interspersed by cattle farming and agroforests; they can cross relatively open landscapes in search ofisolated feeding trees.

Food and Feeding. Hoffmann’s Two-toed Sloth is an arboreal herbivore and generalist. It eats leaves, fruits, flowers buds, twig tips, young stems, and apparently some animal material. In captivity, it eats an average of 350 g/day. Compared with three-toed sloths, Hoffmann’s Two-toed Sloths use a greater number of trees and can disperse more to find food. In Costa Rica, they can use as many as 34 different tree species as food. In forest fragments of Colombia, Hoffmann’s Two-toed Sloths were observed using and feeding preferably on Brownea ariza ( Fabaceae ) during dry seasons.

Breeding. Hoffmann’s Two-toed Sloths reproduce year-round. Estrus lasts 5-7 days; ovarian cycle is ¢.25 days. A female in estrus seems to initiate mating and can approach and rub their anogenital region against a male. Gestation lasts 340-378 days; interbirth interval is c.15 months. Females give birth to single young and are not sexual mature before c.2 years of age. Young Hoffman’s Two-toed Sloths are dependent on their mothers for 139-208 days. In agroforest environments of Costa Rica, mating system is a mix of polygyny with promiscuity, and strategies of females play important roles in determining mating. Females use mate switching as a strategy to enhance genetic diversity or possibly to select high-quality males. Juveniles and subadults have similar rates of survival, which are lower than adult survival. Hoffmann’s Two-toed Sloths live up to 32 years in captivity.

Activity patterns. Hoffmann’s Two-toed Sloths are nocturnal and are usually active from 19:30 h to 05:30 h. They spend most of their time in forest canopies and descend to the ground every 3-8 days to defecate and urinate. In the wild, they are active c.11 h/day through most of the night; in captivity, activity is restricted to c.4 h/day. They spend much of their time resting and sleeping. Continuous activity ranges from 30 minutes to ten hours (average 7-6 hours) and involves foraging and grooming, mostly self-grooming.

Movements, Home range and Social organization. Hoffmann’s Two-toed Sloths are solitary; they spend most of their time in forest canopies to forage, rest, sleep, and breed. They can move up to 300 m/night. Densities are 0-008-1-5 ind/ha. Mean home ranges are 2-5-21-5 ha and are highly variable, especially among adult males (1-1-139-6 ha). Interactions among individuals are rare, usually restricted to breeding activities or between mothers and their infants. Adult males are generally segregated, with most individuals maintaining exclusive use of parts of their home ranges. An average of 3-2 females occurs in home range of an adult male. In captivity, Hoffmann’s Two-toed Sloths tolerate being kept in pairs or in small groups. Female two-toed sloths can interact after parturition or during care of infants. Females carry their infants on their ventral or dorsal regions, and infants become independent c.6 months old. Dispersal seems to be female-biased.

Status and Conservation. CITES Appendix III (Costa Rica). Classified as Least Concern on The IUCN Red List. There are no major conservation threats to Hoffmann’s Two-toed Sloths, and they occur in many protected areas. Northern populations, especially in Colombia and Central America, are declining mainly because of severe habitat degradation and fragmentation. Hunting for illegal trade also is a concern; wild-caught individuals, especially young, are sold as pets to tourists in Colombia. In agroforests in Costa Rica, Hoffmann’s Two-toed Sloths are exposed to pesticides.

Bibliography. Acevedo-Quintero et al. (2011), Branford et al. (2014), Eisenberg & Redford (1999), Garcés-Restrepo et al. (2017), Gardner & Naples (2008), Gilmore et al. (2000, 2001), Goodwin (1946), Hautier et al. (2016), Hayssen (2011a), Herra (2015), Jones (1977), McCarthy et al. (1999), Mendoza et al. (2015), Montgomery & Sunquist (1974), Moraes-Barros & Arteaga (2015), Pauli, Mendoza et al. (2014), Pauli, Peery et al. (2016), Peery & Pauli (2012, 2014), Plese & Chiarello (2014), Plese et al. (2016), Reyes-Amaya et al. (2015), Rezende et al. (2013), Tirira (2017), Vaughan et al. (2007), Voirin et al. (2013), Wetzel (1985a), Wetzel & de Avila-Pires (1980).

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Subspecies and Distribution. C.h.hoffmanniPeters,1858—fromSHondurasSEtoNW&NColombia,WoftheAndes. C.h.agustinusJ.A.Allen,1913—fromNWVenezuelaSthroughCColombiatoNEcuador. C.h.capitalisJ.A.Allen,1913—SWColombiaandWEcuador. C.h.juruanusLLonnberg,1942—SWBrazilianAmazon(AmazonasandAcrestates),SEPeru,andNBolivia. C.h.pallescensLLonnberg,1928—extremeSColombia(PutumayoDepartment),EEcuador,andEPeru.DistributionofHoffmann’sTwo-toedSlothinBrazilisunclear,andfurthersurveysareneeded.TherearetwodoubtfuloutlyingrecordsfromnorthernMatoGrossoState,Brazil.TheselocalitiesarenearorwithindistributionofLinnaeus’sTwo-toedSloth( C.h. didactylus ), suggesting possible misidentification.