Studying the timing of the main events of embryonic and fetal development may clarify the strategies adopted by species to maximize neonatal survival and the consequences of these events for their life history. This study describes bone development during the fetal phase of the lowland paca (Cuniculus paca), comparing it with other precocial or altricial species, and its relationship with the species’ adaptive strategies. A total of 102 embryos/fetuses obtained over the course of 17 years through collaboration with local subsistence hunters in the Amazon were analyzed. Measurements of mineralization of the axial and appendicular skeletons were performed by ultrasonography using a 10–18‐MHz linear transducer. The chronological order of occurrence of mineralization in relation to the total dorsal length (TDL) was: skull (TDL = 4.1 cm); vertebral bodies (TDL = 4.6 cm); scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula (TDL = 6.7 cm); ribs (TDL = 7.8 cm); clavicle (TDL = 8.5 cm); metacarpi/metatarsi (TDL = 11 cm); phalanges (TDL = 15 cm); tarsus (TDL = 18 cm); patella (TDL = 23 cm); and carpus (TDL = 27.2 cm). Secondary ossification centers first appeared in the femoral distal epiphysis (TDL = 16.6 cm) and tibial proximal epiphysis (TDL = 18.4 cm). Advanced fetuses (TDL > 30 cm, 97% gestational period) presented mineralization in all primary and most secondary centers. Compared to other species, paca neonates have a well‐developed skeletal system at birth, which is important for their independent postnatal locomotion. Our results may contribute to the monitoring of bone development in other wild species, helping us to understand their life history, and serving as parameters for comparisons between precocial and altricial mammals.

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Background Comparative studies of kidney morphophysiology in nonhuman primates can help us investigate interspecies differences in growth and aging patterns. Methods We tested the effect of age and sex in renal morphophysiology in 21 Alouatta caraya and 21 Sapajus apella (age range = 0.5–26 years) by ultrasound, red blood cell (RBC) count, and kidney function tests. Results A. caraya had greater growth rate and absolute renal volume than S. apella, but the latter showed a greater relative renal volume and RBC count. There was a negative relationship between RBC and age, a positive relationship between creatinine and body mass, and an apparent negative relationship between creatinine and age only in S. apella. Conclusions Our results indicate that A. caraya has a faster aging mechanism than S. apella, and the higher relative kidney volume in S. apella is suggestive of high metabolic demands in this species.

The hormone dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are the most abundant circulating steroids in human and some nonhuman primates, and have been implicated in development, aging and in stress modulation. We aimed to validate a commercially available enzyme immunoassay kit to measure DHEAS in feces and serum of three platyrrhine primate species (Alouatta caraya, Aotus azarae infulatus, and Sapajus apella) in captivity. We collected serum samples from one male and one female from each species. To validate the kit for fecal samples, we conducted a physiological validation by administering DHEA orally to one adult female of each species. We also measured fecal DHEAS levels in four female Alouatta caraya individuals during the third semester of gestation and in two females following parturition. We obtained a total of 54 fecal samples and 6 serum samples from 10 individuals. We validated the assay analytically by testing parallelism and accuracy tests in both fecal and serum extracts for all species. We observed a peak in DHEAS 24 h following oral DHEA administration in all three species, with A. caraya presenting the strongest response and highest baseline concentrations. DHEAS levels were elevated in pregnant A. caraya (57,843.86 ± 37,160.31 ng/g) and declined after parturition (1,539.07 ± 2,894.74 ng/g). Our results demonstrated that these platyrrhines secrete measurable concentrations of DHEAS, with A. caraya secreting levels comparable to those of catarrhines. The EIA kit is valid for quantification of fecal and serum DHEAS, and it is useful for studies on stress and primate evolution.

O Letramento Funcional em Saúde (LFS) é um dos determinantes sociais estabelecidos que indica a capacidade de se obter, analisar e aplicar as informações médicas, no entanto, ainda não existe um formulário aplicado à Medicina Veterinária. No presente trabalho, foi criado um teste de Letramento Funcional em Saúde Animal (LFSA) para ser avaliada a compreensão de tutores de cães e gatos a respeito de informações comumente utilizadas nas prescrições veterinárias. Apesar de entenderem as orientações verbais, 62% têm dificuldade para compreender os horários das medicações e termos técnicos (74%). Foi constatada a existência de associação entre o grau de LFSA e o nível de escolaridade e renda. Tutores com ensino fundamental e renda de até três salários-mínimos (58%) exibiram letramento de crítico (42%) a básico (61%), que foi associado à dificuldade de letramento (p<0,001 e p = 0,04). O teste apresenta questões rápidas e práticas e pode ser aplicado pelo médico-veterinário antes da prescrição e melhorar a comunicação com o tutor.

The owl monkeys (Aotus sp.) are considered excellent experimental models for biomedical research, in particular for studies on vision 1 and malaria. 2 For such studies, the use of animals with normal liver function is crucial to ensure an adequate experimental protocol. The liver is involved in several physiological functions, including biosynthesis, detoxification, digestion, and immunity, being the major elimination pathway for several drugs. 3 Hepatic diseases may impair these functions and result in accumulation of toxins in the body, 4 which can affect experimental treatments. Monitoring hepatic function is therefore essential to avoid the impact of pre-existing liver conditions in the outcome of experiments.Liver conditions such as fatty liver disease, spontaneous gallstone formation, and focal nodular hyperplasia have been reported in Aotus trivirgatus, 5 Papio sp, 6 Saimiri sciureus, 7 Macaca fascicularis, 8

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The study of fetal development allows for evaluating the different strategies adopted by mammal species to maximize neonatal survival. Autonomous locomotion is fundamental for newborns to perform foraging activities and increases newborn survival from predation. In this study, we assess the gestational bone development of 53 col-