A recently published taxonomic review (Miranda et al. 2023) proposes to split the northern (in southern Bahia and Sergipe) and southern subpopulations (Espírito Santo and Rio de Janeiro) into two species - Bradypus torquatus (Bahia and Sergipe) and Bradypus crinitus (Rio de Janeiro and Espírito Santo), respectively. The subpopulations were already considered genetically distinct, according to previous studies (Lara-Ruiz et al. 2008, Schetino et al. 2017). This recent analysis (Miranda et al. 2023), based on coalescent delimitation using mitochondrial and nuclear DNA, morphological analyses and field observations, recognizes that they are in fact two species, B. torquatus and B. crinitus.

The Maned Sloth was occasionally classified as a subgenus of Bradypus or placed in his own genus, Scaeopus (Hayssen 2009, Wetzel and Ávila-Pires 1980) due to its morphological distinctiveness. A growing number of molecular studies supports this differentiation (Gibb et al. 2016, Schetino et al. 2017, Ruiz-Garcia et al. 2020), but additional studies are needed to confirm this.

Bradypus crinitus and B. torquatus were previously considered a single species, which was listed as Vulnerable. However, in 2023 a taxonomic review provided evidence that the subpopulations in Rio de Janeiro and Espírito Santo should be considered a separate species (B. crinitus). The taxonomic split led to a significant decrease of the area of distribution, extent of occurrence (EOO) and area of occupancy (AOO) of both species. The EOO of B. crinitus has been estimated at 41,221 km² and its AOO at 392 km². The latter is smaller than the threshold for the Endangered category under criterion B2. The remaining forest within its range declined continuously in the last 30 years due to deforestation and forest disturbance associated with edge effects and illegal logging, among other anthropogenic factors. The available information indicates that the species does not venture more than 200 m from the nearest forest edge. The majority (more than 80%) of the remaining forest fragments within the range of this species are smaller than 10 hectares and are at least 200 m apart; hence, the population is severely fragmented.

The largest declines within its AOO were observed in the state of Espírito Santo, which encompasses 80% of the current AOO and probably the largest share of the remaining southern Maned Sloth population. Furthermore, this species, like all sloths, is threatened by vehicle collisions, a growing impact considering current and future city sprawl and road development in the region of the Atlantic forest occupied by the species. Electrocution in power lines and attacks by dogs are further impacts associated with forest fragmentation and city sprawl. Poaching or capture for the illegal animal trade might be minor threats whose impact, nevertheless, should not be ignored, particularly in smaller forest fragments where the population is down to a few individuals, leading to a continuing decline in the number of mature individuals and subpopulations. Considering all this, Bradypus crinitus is listed as Endangered under criterion B2ab(ii,iii,iv,v).

The range of Bradypus crinitus is divided into two geographically separated subpopulations in the Atlantic coastal forests of Espírito Santo and Rio de Janeiro states in eastern Brazil. Its northern subpopulation is currently delimited to the north by the right bank of Doce River and to the south by the Itabapoana River. The southern subpopulation is limited to the north by the Paraiba do Sul River and to the south by the proximities of the Cabo Frio region in the north-central portion of Rio de Janeiro (Boffy et al. 2010, Santos et al. 2019). The area of distribution is estimated at 28,525 km², and the species ranges from sea level to 1,400 m Asl. The extent of occurrence is 41,221 km² (calculated from Minimum Convex Polygon) and the area of occupancy is 392 km².

The northern and southern subpopulations are separated by a natural biogeographic gap between southern Espírito Santo and northern Rio de Janeiro states. This gap is likely linked to a higher degree of deciduity in the forests of these regions (Hirsch and Chiarello 2012). Nevertheless, recent sightings suggest that the species might have a slightly broader distribution in Rio de Janeiro than is indicated by the available data (Boffy et al. 2010; P. M. Santos, pers. comm. 2023). The species has been reported, but not confirmed, from extreme northern Minas Gerais on the left bank of Jequitinhonha River. Bradypus crinitus has been introduced in some National Parks in Espírito Santo (Caparaó National Park) and Rio de Janeiro (Tijuca National Park), among other areas, but there is no evidence that the species is currently present in these sites. 

Based on a minimum convex polygon drawn around the area of distribution, the extent of occurrence (EOO) of this species is 41,221 km². The area of occupancy (AOO) within this EOO was estimated at 392 km² based on a 2x2 km² grid overlay on the range map and counting only cells with forested areas, as this arboreal species depends on trees for its survival.

In some parts of lowland (Aracruz municipality) and lower-montane (Santa Teresa and Santa Maria do Jetibá municipalities) Espírito Santo, the species seems to be locally abundant in forest fragments (Santos et al. 2016, Santos et al. 2019) although estimates of population density are not yet available.

In general, little genetic diversity is exhibited within individual populations (Moraes-Barros et al. 2006, Lara-Ruiz et al. 2008). Overall, the global population of B. crinitus is assumed to be decreasing in response to the continuing loss, fragmentation and disturbance of suitable forest, the Atlantic Forest (SOS Mata Atlântica and INPE 2023, Santos et al. 2024).

This strictly arboreal species is found in wet tropical forest, most typically in areas with an annual precipitation of 1,200 mm or higher and lacking a dry season. Most records are from evergreen forests, and just a handful of sightings are from semi-deciduous forests (Hirsch and Chiarello 2012). It can be found in secondary forest habitats, and some animals have been sighted in forest fragments as small as 20 ha, although the long-term persistence of populations at these sites is unknown (Santos et al. 2016).  In fact, a recent analysis indicates that 82.6% of the total habitat area (66% of the AOO)  is in patches smaller than 10 hectares, and an additional 13% of the total habitat area (18% of the AOO) is between 10 and 50 hectares. Less than 1% of habitat patches (3.6% of AOO) are larger than 250 hectares (P.M. Santos unpublished data 2025). Forest fragments are at least 200 m apart, which the experts on the species consider the likely dispersal limit of this arboreal species (A.G. Chiarello pers. comm. 2024). Hence, the population is considered to be severely fragmented.

It is a strict folivore at the population level, with individuals feeding on a relatively small number of food plants; Chiarello (1998) found that leaves from 21 species formed 99% of the diet of three radio-collared animals, but each fed on 7-12 plant species only. Like other congeneric sloths, animals descend from trees periodically to urinate and defecate, although this has been rarely observed (A.G. Chiarello, pers. comm. 2024). The females give birth to one young annually, predominantly at the end of the wet season and beginning of the dry season (February-April), and copulation concentrates in the late dry and early wet seasons (August–October; Dias et al. 2009). Sexual maturity is probably reached between the second and third year and longevity in the wild is over 12 years (Lara-Ruiz and Chiarello 2005).

The expansion of pasturelands and, secondarily, wood and pulp plantations, urban sprawl, and agricultural areas —with the consequent habitat loss — are the main threats to the species (Santos et al. 2024). Although the rate of deforestation in the Atlantic forest of eastern Brazil has decreased in the last three decades, it has not stopped and, in fact, has rebounded a bit in the last five years (SOS Mata Atlântica and INPE 2023), so the pressure on habitat continues. This is particularly true in the state of Espírito Santo, where illegal or unregulated deforestation for several reasons, including urban sprawl and agricultural expansion (especially for pasturelands), is still taking place (Santos et al. 2024).

The isolation of small subpopulations can lead to a drastic reduction in gene flow. In areas with less than 20% of habitat available for the species, surrounded by open areas, the occupancy probability can reach 0% (Santos et al. 2019). The genetic integrity of distinct subpopulations might be threatened by the release of confiscated animals at different sites without knowledge or understanding of their origins. Accidental mortality of B. crinitus on roads may also be a threat. In fact, roadkill might be considered a growing impact due to road expansion or duplication, as is the case of the BR-101, an important road already being duplicated in Rio de Janeiro and soon to be duplicated also in Espírito Santo. Several other significant threats need to be addressed, including attacks by domestic dogs and deaths caused by electrocution (Santos et al. in press). 

Bradypus crinitus is affected by the increased seasonality and prolonged droughts, as the species does not seem to tolerate deciduous forests and the species' body temperature varies with ambient temperature (Chiarello 1998). Increase in temperature and seasonality might become more relevant due to climate change. Furthermore, such new conditions can affect resource availability, as prolonged droughts can increase the risk of fires and change local vegetation (Santos et al. 2022).

Although the species is not actively pursued, individuals might sometimes fall victims of subsistence hunting or for traditional medicine when spotted by local people (Teixeira et al. 2020). Hunting is legally forbidden in Brazil, but enforcement is ineffective. Very few specimens exist in museums so the pressure from scientific collections is practically inexistent.

Bradypus crinitus is present in a number of protected areas, such as the Biological Reserves of Augusto Ruschi (Espírito Santo), Poço das Antas (Rio de Janeiro) and União (Rio de Janeiro), among others. The species has been included in a Brazilian Action Plan (PAN Primatas da Mata Atlântica e da Preguiça-de-coleira; ICMBio 2019), when it was considered B. torquatus. Therefore, a new review of conservation goals and actions for this species is necessary, since it may now be more threatened.

The low genetic diversity within fragmented subpopulations indicates a need to develop corridors of suitable habitat between these subpopulations. Confiscated animals should be genetically characterized to determine the most appropriate release site. Data on dispersal ability, sex ratio, mating system, and population density are virtually unknown but important for conservation planning and monitoring.