RESUMO

Although extinct sloths exhibited a wide range of dietary habits, modes of locomotion, and occupied various niches across the Americas, modern sloths are considered quite similar in their habits. The dietary habits of living sloths can be directly observed in the wild, and understanding the mechanical behavior of their jaws during chewing through finite element analysis (FEA) provides a valuable validation tool for comparative analysis with their extinct counterparts. In this study, we used FEA to simulate the mechanical behavior of sloth mandibles under lateral mastication loads, using it as a proxy for oral processing. Our research focused on the six extant sloth species to better understand their diets and validate the use of FEA for studying their extinct relatives. We found that all living sloths have the predominancy of low-stress areas in their mandibles but with significant differences. Choloepus didactylus had larger high-stress areas, which could be linked to a reduced need for processing tougher foods as an opportunistic generalist. Bradypus variegatus and Choloepus hoffmanni are shown to be similar, displaying large low-stress areas, indicating greater oral processing capacity in a seasonal and more competitive environment. Bradypus torquatus, Bradypus pygmaeus, and Bradypus tridactylus exhibited intermediary processing patterns, which can be linked to a stable food supply in more stable environments and a reduced requirement for extensive oral processing capacity. This study sheds light on extant sloths' dietary adaptations and has implications for understanding the ecological roles and evolutionary history of their extinct counterparts.

Assuntos

RESUMO

The goal of this study is to provide a taphonomic analysis of bone fragments found in harpy eagle nests in the Brazilian Amazonia, utilizing the largest sample of prey remains collected to date. Harpy eagle kill samples were collected from nine nests, between June 2016 and December 2020 in Mato Grosso, Brazil. We identified the specimens, calculated the number of identified specimens (NISP) and minimum number of individuals (MNI). These metrics were used to estimate bone survivability and fragmentation. A total of 1661 specimens (NISP) were collected, representing a minimum number of 234 individuals (MNI). We identified at least nine species of primates, which represent 63.8% of the individuals in the kill sample. Harpy eagles preyed mostly on the medium-sized capuchin and bearded saki monkeys (28.2% of the MNI), and two-toed sloths (17.7% of the MNI). The large woolly monkeys also represented a significant portion of the sample (11.5% of the MNI). Three distinct patterns of bone survivability were found, one characterizing two-toed sloths, another characterizing medium-sized monkeys, and a third typical of woolly monkeys. We conclude that harpy eagle predation leaves an identifiable signature on the prey with a bone survivability pattern specific to each taxon. The intertaxon variations observed in the taphonomic signatures of harpy eagle kills should be taken into account when evaluating the potential influence of these raptors as accumulators of bone material in both paleontological and neontological assemblages.

Assuntos

RESUMO

Nowadays, wild animals are threatened by humans, with the number of species and individuals decreasing during recent years. Wildlife rescue centers play a vital role in the conservation of wildlife populations. This study aims to describe a new release technique, the Speaker Method, to rescue and facilitate the reunion of different baby mammals that arrived at a wildlife rescue center with their mothers within their natural habitat, avoiding the need for captivity. This method is based on a recorded baby's cry played on a speaker to make a "call effect" in the mother. The efficacy of the Speaker Method for babies' reunion with their mothers was 45.8% in Hoffmann's two-toed sloths (Choloepus hoffmanni) and 91.9% in brown-throated sloths (Bradypus variegatus). Among the mantled howler monkeys (Alouatta palliata), 50% of the babies could be released using this new technique. The findings suggest that the method could be helpful in the early release of young individuals, highlighting higher release outcomes in these three species compared to traditional nursery care provided by human caretakers, who face inherent difficulties in raising young animals without their mothers.

RESUMO

It is usually beneficial for species to restrict activity to a particular phase of the 24-hour cycle as this enables the development of morphological and behavioural adaptations to enhance survival under specific biotic and abiotic conditions. Sloth activity patterns are thought to be strongly related to the environmental conditions due to the metabolic consequences of having a low and highly variable core body temperature. Understanding the drivers of sloth activity and their ability to withstand environmental fluctuations is of growing importance for the development of effective conservation measures, particularly when we consider the vulnerability of tropical ecosystems to climate change and the escalating impacts of anthropogenic activities in South and Central America. Unfortunately, the cryptic nature of sloths makes long term observational research difficult and so there is very little existing literature examining the behavioural ecology of wild sloths. Here, we used micro data loggers to continuously record, for the first time, the behaviour of both Bradypus and Choloepus sloths over periods of days to weeks. We investigate how fluctuations in the environmental conditions affect the activity of sloths inhabiting a lowland rainforest on the Caribbean coast of Costa Rica and examined how this might relate to their low power lifestyle. Both Bradypus and Choloepus sloths were found to be cathemeral in their activity, with high levels of between-individual and within-individual variation in the amounts of time spent active, and in the temporal distribution of activity over the 24-hour cycle. Daily temperature did not affect activity, although Bradypus sloths were found to show increased nocturnal activity on colder nights, and on nights following colder days. Our results demonstrate a distinct lack of synchronicity within the same population, and we suggest that this pattern provides sloths with the flexibility to exploit favourable environmental conditions whilst reducing the threat of predation.

Assuntos

RESUMO

Background: Wildlife has been recently recognized as an environmental reservoir for antimicrobial resistance (AMR). However, less information on this topic is available in animals released back into the wild after rehabilitation in wildlife facilities, compared with studies performed exclusively in captive or free-ranging wildlife. This study aimed to evaluate the potential influence of captivity and/or treatment while in captivity of wild sloths on the AMR and virulence profiles of sloths' Enterobacterales. Methods: Oral and rectal swab samples were collected from 39 two-finger (Choloepus hoffmanni) and three-finger sloths (Bradypus variegatus) of Costa Rica (n = 78) and analyzed using conventional bacteriological techniques. A generalized linear mixed model was applied to estimate the isolates' multiple antimicrobial resistance and virulence indices as a function of animal status. Results: A considerable level of resistance was detected, especially for Citrobacter youngae and Escherichia coli, with 17.5% of isolates classified as multidrug-resistant. Virulence indices of isolates from rehabilitated sloths were significantly higher than the ones from sloths being hand-reared for shorter periods. Conclusions: To our knowledge, this is the first description of sloths' antimicrobial resistant Enterobacterales, suggesting that sloths' rehabilitation and consequent exposure to humans, may promote the selection of bacteria with higher virulence. Ultimately, these bacteria may represent a threat to human and animal health due to their zoonotic potential and AMR and virulence profiles.

Assuntos

RESUMO

We sequenced the complete mitogenome of 39 sloths (19 Bradypus variegatus, 4 B. tridactylus, 1 B. pygmaeus, 1 B. torquatus, 4 Choloepus didactylus, and 10 C. hoffmanni). A Bayesian tree (BI) indicated a temporal split between Bradypus and Choloepus around 31 million years ago (MYA, Oligocene) and the other major splits within each genera during the Miocene and Pliocene. A haplotype network (MJN) estimated a lower temporal split between the sloth genera (around 23.5 MYA). Both methods detected the ancestor of B. torquatus as the first to diverge within Bradypus (21 for BI and 19 MJN), followed by that of the ancestor of B. tridactylus. The split of B. pygmaeus from the common ancestor with B. variegatus was around 12 MYA (BI) or 4.3 MYA (MJN). The splits among the previous populations of B. variegatus began around 8 MYA (BI) or 3.6 MYA (MJN). The trans-Andean population was the first to diverge from the remaining cis-Andean populations of B. variegatus. The genetic differentiation of the trans-Andean B. variegatus population relative to the cis-Andean B. variegatus is similar to that found for different species of sloths. The mitogenomic analysis resolved the differentiation of C. hoffmanni from the C. didactylus individuals of the Guiana Shield. However, one C. didactylus from the Colombian Amazon specimen was inside the C. hoffmanni clade. This could be the first example of possible natural hybridization in the Amazon of both Choloepus taxa or the existence of un-differentiable phenotypes of these two species in some Amazonian areas.

Assuntos

RESUMO

We screened for antibodies to 16 arboviruses in four populations of free-ranging sloths in Costa Rica. Blood samples were taken from 16 Hoffman's two-toed sloths (HTSs; Choloepus hoffmanni ) and 26 brown-throated sloths (BTSs; Bradypus variegatus ) over a 3-yr period. We used serologic assays to detect antibodies against 10 arboviruses previously described in sloths (St. Louis encephalitis [SLEV], Changuinola, Venezuelan equine encephalitis, Ilheus [ILHV], Oropouche, Mayaro, Utinga, Murutucu, Punta Toro, and vesicular stomatitis [VSV] viruses) and six arboviruses not described in sloths (Rio Grande, West Nile [WNV], eastern equine encephalitis, Piry, Munguba, and La Crosse viruses). Overall, 80% of sloths had detectable antibodies to SLEV, 67% had antibodies to ILHV, 32% to Punta Toro virus, 30% to Changuinola virus, 15% to WNV, 14% to VSV, 11% to Venezuelan equine encephalitis virus, and 10% to Rio Grande virus. No samples had detectable antibodies to the remaining eight viruses. We found a significant increase in prevalence of antibody to VSV in HTSs between 2005 and 2007, and for WNV antibody between 2005 and 2006. We found no significant differences in the prevalences of antibodies to the sampled viruses between the two locations. Antibody prevalences were significantly higher in HTSs than in BTSs for SLEV in 2005. Antibody-positive results for ILHV were likely due to cross-reaction with SLEV. The novel finding of antibodies to Rio Grande virus in sloths could be due to cross-reaction with another phlebovirus. These findings might have implications for land management and domestic animal health. Due to the nature of the study, we could not determine whether sloths could represent amplification hosts for these viruses, or whether they were only exposed and could be used as sentinel species. Further studies are needed to fully characterize arboviral exposure in sloths.

Assuntos

RESUMO

Descreve-se o caso de uma fêmea adulta de preguiça-real (Choloepus sp.), vítima de atropelamento. O animal apresentou fratura de mandíbula e perda de parte da língua, o que prejudicou sua alimentação. Permaneceu por dez meses sob cuidados e durante esse período foram necessários tratamentos com antibióticos e antiiflamatórios, cujas doses usadas se mostraram eficazes. Após recuperação clínica do quadro inicial, o animal ainda recusava qualquer alimento sólido e por três meses foi alimentado diariamente apenas com uma dieta líquida a base de frutas, legumes, iogurte, linhaça moída, ovo, flores e folhas. Gradualmente passou a tentar comer brotos de Cecropia sp. e somente no oitavo mês se alimentava relativamente bem sozinho. Embora as preguiças sejam consideradas praticamente folívoras, o indivíduo se adaptou bem à dieta liquida, já que durante todo o processo apresentou consistência normal das fezes e boa condição clínica. Apesar de ter gasto oito meses para se readaptar à ausência de parte da língua, conclui-se que todo o manejo veterinário e alimentar foi bem sucedido.(AU)

The case of an adult female of two-toed-sloth(Choloepus sp.), victim of running over isdescribed. The animal had jaw fracture andloss of part of the tongue, which hamperedtheir food. Remained under care for tenmonths, during which treatment withantibiotics and anti-inflammatory were neededand whose doses used were effective. Afterclinical recovery of the initial condition, theanimal still refused any solid food and for threemonths was fed daily with a liquid diet basedon fruits, vegetables, yogurt, ground flaxseed,eggs, flowers and leaves. Gradually came totry to eat sprouts Cecropia sp. and only aftereight months spent to feed relatively wellalone. Although sloths are consideredfolivores, the individual has adapted well to theliquid diet, since during the whole process hadnormal stool consistency and good clinicalcondition. Despite having spent eight monthsto readjust to the absence of part of the tongue,it is concluded that all veterinary and feedingmanagement was successful.(AU)

Assuntos

RESUMO

Descreve-se o caso de uma fêmea adulta de preguiça-real (Choloepus sp.), vítima de atropelamento. O animal apresentou fratura de mandíbula e perda de parte da língua, o que prejudicou sua alimentação. Permaneceu por dez meses sob cuidados e durante esse período foram necessários tratamentos com antibióticos e antiiflamatórios, cujas doses usadas se mostraram eficazes. Após recuperação clínica do quadro inicial, o animal ainda recusava qualquer alimento sólido e por três meses foi alimentado diariamente apenas com uma dieta líquida a base de frutas, legumes, iogurte, linhaça moída, ovo, flores e folhas. Gradualmente passou a tentar comer brotos de Cecropia sp. e somente no oitavo mês se alimentava relativamente bem sozinho. Embora as preguiças sejam consideradas praticamente folívoras, o indivíduo se adaptou bem à dieta liquida, já que durante todo o processo apresentou consistência normal das fezes e boa condição clínica. Apesar de ter gasto oito meses para se readaptar à ausência de parte da língua, conclui-se que todo o manejo veterinário e alimentar foi bem sucedido.

The case of an adult female of two-toed-sloth(Choloepus sp.), victim of running over isdescribed. The animal had jaw fracture andloss of part of the tongue, which hamperedtheir food. Remained under care for tenmonths, during which treatment withantibiotics and anti-inflammatory were neededand whose doses used were effective. Afterclinical recovery of the initial condition, theanimal still refused any solid food and for threemonths was fed daily with a liquid diet basedon fruits, vegetables, yogurt, ground flaxseed,eggs, flowers and leaves. Gradually came totry to eat sprouts Cecropia sp. and only aftereight months spent to feed relatively wellalone. Although sloths are consideredfolivores, the individual has adapted well to theliquid diet, since during the whole process hadnormal stool consistency and good clinicalcondition. Despite having spent eight monthsto readjust to the absence of part of the tongue,it is concluded that all veterinary and feedingmanagement was successful.

Assuntos