Farming non-typical sentient species: ethical framework requires passing a high bar.

More widespread farming of species not typically used as livestock may be part of a sustainable approach for promoting human health and economic prosperity in a world with an increasing population; a current example is peccary farming in the Neotropics. Others have argued that species that are local to a region and which are usually not farmed should be considered for use as livestock. They may have a more desirable nutrient profile than species that are presently used as livestock. It may also reduce the pressure from hunting on other wild species, and cause less environmental damage than exotic species. We propose a sentiocentric utilitarian framework that could be used to decide whether species that are local, but generally not used as livestock, should be farmed. To illustrate the use of our decision-making framework, we employ two contrasting neotropical case studies: the Spotted Paca (Cuniculus paca) and the Capybara (Hydrochoerus hydrochaeris). We argue that it may be acceptable to use non-sentient species that are typically not farmed as livestock. However, research should determine whether farming them offers human, environmental or sustainability benefits. In addition, we recommend that if invertebrate species are considered for farming, research should be conducted to determine the likelihood that they are sentient. Finally, given the ethical failings of current livestock farming practices, we argue that a high bar must be met if 'new' species that are sentient are to be farmed.

Impact of environmental variables on some reproductive metrics of white-lipped peccaries (Tayassu pecari) raised in Atlantic Forest of Brazil.

Knowledge on male reproductive physiology is essential for the development of effective conservation strategies. This study investigated the influence of environmental variables on certain reproductive metrics in white-lipped peccaries (Tayassu pecari) raised in the Atlantic Forest. After anesthetization, testicular and cauda epididymis biometry were evaluated in nine adult male individuals subjected to electroejaculation. Semen was evaluated for volume, pH, concentration, total number of sperm, sperm morphology, membrane integrity, and kinematic parameters. Concurrently, environmental variables were collected from the day before, for the previous 14 days (estimated for sperm maturation in epididymis), and the period of 51-55 days (corresponding to the spermatogenic cycle) before semen collection. Overall, it was observed that rainfall is the most important environmental variable influencing the reproductive parameters of white-lipped peccaries, being positively correlated with the amplitude of lateral sperm head displacement (ρ = 0.62, P < 0.05) and the appearance of proximal cytoplasmic droplets in sperm (ρ = 0.62, P < 0.05). In addition, the testicular biometry of the species is influenced by the set of environmental variables of air temperature, rainfall, and relative humidity (ρ ≥ 0.60, P < 0.05). On the other hand, epididymal biometric data showed numerous correlations between cauda epididymis metrics and sperm parameters (ρ = 0.68, P < 0.05). This information will be useful to improving conservation strategies for these animals, contributing to their management in captivity and to reintroduction programs, especially in the Atlantic Forest where the species is declining.

Production of multimodal signals to assert social dominance in white-lipped peccary (Tayassu pecari).

In this study we aimed to examine whether the 'redundancy' (a backup function to ensure the signal transmission) or 'multiple messages' (sensory communication system in combination) hypothesis would explain the function of multimodal communication of white-lipped peccaries (Tayassu pecari-WLPs). We also aimed to assess the individual factors (the social rank and sex of the sender) influencing the production of, and responses to unimodal and multimodal signals. We determined the social rank of 21 WLPs living in two captive groups and quantified the production of unimodal and multimodal signals when displaying threatening and submissive behaviors. WLPs most often produce multimodal signals independent of a previous unimodal signal failure, which suggests that they were adding more information, such as the sender's size, rather than merely increasing efficacy by engaging a different receiver's sensory channel. There was no effect of the sender's sex in the production of, and responses to, multimodal signals. However, the higher the sender's social rank, the greater the production of multimodal signals when WLPs were displaying threatening behaviors; whereas the lower the sender's social rank, the greater the production of multimodal signals when displaying submission behaviors. Multimodal signals elicited more non-aggressive responses than did the unimodal signals when displaying a threat. Moreover, the higher the sender's social rank, the greater the occurrence of non-aggressive responses to multimodal signals when displaying a threat; whereas the opposite occurred when displaying submission. Our findings support the 'multiple messages' hypothesis to explain the function of multimodal signaling during agonistic interactions in WLPs. Additionally, both the production of, and responses to, multimodal signals are related to the sender's social rank. These results allow us to suggest that the production of multimodal signals may have a key role in mitigating conflict and thus promoting group cohesion among white-lipped peccaries.

Responses to environmental enrichment are associated with personality characteristics in chestnut-bellied seed finches (Sporophila angolensis).

Environmental enrichment (EE) is used to promote natural behaviours in captive animals and may hold promise as a form of pre-release training, a strategy for improving coping skills of translocated birds. We investigated the use of EE to enhance foraging and vigilance behaviours of captive Sporophila angolensis, which may be related to post-release survival. We also evaluated whether consistent individual behavioural differences affected birds' responses to EE. We submitted 19 captive seed-finches to three short-term challenges: tonic immobility (TI), new environment (NE) and new object (NO) tests. TI behaviour is related to fear/escape response to potential predators and novelty tests (NE and NO) assess neophobia, which are ecologically relevant personality traits influencing the shyness-boldness continuum. We noted a pronounced variability among the individuals' personality traits, both in their fear and escape-related responses in the TI test and along shy/bold z-scores in NE and NO tests. During a period of enrichment, birds spent more time foraging and less time in vigilance states compared with both control phases. Personality traits of the birds affected their responses to enrichment with bolder birds spending more time foraging. The EE-related decrease in vigilance was independent of the birds' personality traits. Our findings highlight interactions between personality and rearing environment that may impact post-release outcomes for translocated animals.

Validation of complementary non-invasive tools for stress assessment in spotted paca (Cuniculus paca).

Monitoring the concentration of glucocorticoid metabolites (GCMs) in faecal samples is a non-invasive tool for physiological stress evaluation, particularly useful when studying wild species. However, both negative and positive stimuli (distress and eustress, respectively) can lead to a rise in glucocorticoids. Thus, besides validating whether GCM concentration in faeces reflects endogenous adrenal activity, we also need to identify behavioural indicators of distress to avoid misinterpretation. Therefore, we submitted four adult male spotted pacas (Cuniculus paca) to an exogenous adrenocorticotropic hormone (ACTH) challenge-test in a Latin square design (4 × 4) to monitor changes in the GCM concentration in faeces. We also aimed to describe behaviours potentially indicative of distress. We collected excreted faeces and video-recorded the animals' behaviours for five consecutive days, one day before and four days after application of the following four treatments: 1st control (no-handling); 2nd control (intra-muscular [IM] injection of saline solution); low-dose ACTH (IM injection of 0.18 ml ACTH); and high-dose ACTH (IM injection of 0.37 ml ACTH). There was a peak in the concentration of GCM in faeces collected 24 h after the injection of the high-dose ACTH treatment. Additionally, independent of the treatments, spotted pacas spent less time on exploration and feeding states, while spending more time in the inactive but awake (IBA) state following the treatment application (challenge day). The use of GCM concentration in faecal samples together with the behavioural changes (less exploration and feeding, and more IBA) showed to be efficient as a non-invasive tool for welfare assessment of farmed spotted paca.

Object Play as a Positive Emotional State Indicator for Farmed Spotted Paca (Cuniculus paca).

We aimed to assess whether object play can be used as a positive emotional state indicator for farmed spotted pacas (Cuniculus paca) by examining its association with other positive welfare markers including affiliative behavior and low-amplitude vocalizations. We submitted six groups of spotted pacas (one male/two females per group) (N = 18) to an ABA experimental design (A1/A2: without ball; B: with three boomer balls). Object play behavior occurred only during phase B (mean = 35.5 s, SE = 6.4). The spotted pacas spent more time in affiliative and exploratory behaviors and less time engaging in agonistic interactions during phase B than in both control phases (A1 and A2) (p < 0.05). Moreover, the spotted pacas emitted more low-amplitude bark vocalizations during phase B than during either control phase (p < 0.05), and such vocalizations have previously been shown to indicate a positive affective state and low arousal level. Because the expression of object play was associated with a decrease in aggression, an increase in affiliative behavior, and an increase in low-amplitude barking, we suggest that object play can be used as a non-invasive indicator of positive emotional state in this species.

Relationships between food shortages, endoparasite loads and health status of golden-headed lion tamarins (Leontopithecus chrysomelas) / Relações entre escassez alimentar, carga endoparasitária e estado de saúde do mico-leão-de-cara-dourada (Leontopithecus chrysomelas)

Abstract Both anthropogenic actions and abiotic parameters, such as rainfall, temperature and photoperiod, can affect fruit and flower availability for animals, which consequently affects nutritional status and thus animals' health. Herein, we investigated whether abiotic factors are related to changes in fruit availability that can lead to changes in feeding behavior and, consequently, in endoparasite load and general health status in two groups of golden-headed lion tamarins (Leontopithecus chrysomelas) living in degraded fragments of Atlantic forest in Southern Bahia, Brazil. We detected that there was a high variation in availability of ripe fruits throughout the year, with lower availability occurring at the end of spring and beginning of summer. Despite this, there was no difference in tamarins' general health status, body mass and blood counts between seasons. This is probably because during native fruit scarcity, the tamarins eat cultivated species, such as banana (Musa spp.) and jackfruit (Artocarpus heterophyllus). Temperature and daylength were negatively correlated with golden-headed lion tamarin endoparasite loads. Contrary to our expectations, endoparasite loads are not linked to fruit scarcity and consequent changes in feeding behavior. Nevertheless, we found higher parasite diversity in the group of golden-headed lion tamarins that occupied the smallest home range. The smaller the area available, the greater the contact with parasites the animal will have, as they are forced to travel constantly along the same routes in the forest, increasing infection risk and re-infection rates. Our results highlight how animals' health is associated with environmental health as well as the need for constant monitoring to ensure the effective conservation of endangered species, such as the golden-headed lion tamarin.

Resumo Parâmetros abióticos, como precipitação, temperatura e fotoperíodo, podem afetar a disponibilidade de frutos e flores para os animais, o que consequentemente afeta o estado nutricional e a saúde dos animais. Neste estudo, investigamos se fatores abióticos estão relacionados com alterações na disponibilidade de frutos, o que pode levar a mudanças no comportamento alimentar e, consequentemente, na carga de endoparasitas e estado de saúde geral em dois grupos de mico-leão-de-cara-dourada (Leontopithecus chrysomelas) que vivem em fragmentos degradados de Floresta Atlântica no sul da Bahia, Brasil. Detectamos que houve grande variação na disponibilidade de frutos maduros ao longo do ano, com menor disponibilidade no final da primavera e início do verão. Apesar disto, não houve diferenças no estado geral de saúde, na massa corporal ou nas contagens de células sanguíneas dos animais entre as estações do ano. Isto provavelmente ocorreu porque durante a escassez de frutos nativos, os micos comem espécies cultivadas, tais como a banana (Musa spp.) e jaca (Artocarpus heterophyllus). A temperatura e a duração do dia foram negativamente correlacionadas com a carga de endoparasitas de mico-leão-de-cara-dourada. Contrário ao previsto, a carga de endoparasitas não está ligada à escassez sazonal de frutos e consequentes mudanças no comportamento alimentar. Entretanto, encontramos maior diversidade de endoparasitas no grupo de mico-leão-de-cara-dourada que usou uma área de vida menor. Quanto menor a área disponível, maior o contato com parasitas, porque os micos são forçados a se deslocar constantemente pelas mesmas rotas na floresta, aumentando o risco de infecção e as taxas de reinfecção. Nossos resultados destacam como a saúde dos animais está associada à saúde ambiental, bem como a necessidade de monitoramento constante para a conservação eficaz das espécies ameaçadas de extinção, como o mico-leão-de-cara-dourada.

Personality and plasticity of defensive behavior in collared peccary (Dicotyles tajacu).

Inter-individual differences in behavior, together with phenotypic plasticity, may play a key role in the reintroduction success of captive-born individuals. Therefore, we aimed to investigate whether and how personality traits affect the plasticity of defensive behavior in collared peccary (Dicotyles tajacu). Twenty-six adult captive-born collared peccaries (12 males and 14 females) were submitted to three short-term challenges for personality assessment. Thereafter, each individual was submitted to four sequential tests, with different degrees of risk, allowing us to assess temporal/context consistencies in personality traits as well as the plasticity of defensive behavior. We noted a pronounced variability among the individuals' boldness trait, while males and females did not differ in their behavioral responses in all tests. Additionally, collared peccaries show behavioral plasticity of defensive behavior across risk conditions. We also verified an association between boldness and defensive behavior in this species: the higher the boldness score, the less time collared peccaries spent on wariness behaviors in the higher risk condition. The link between personality traits and behavioral plasticity of collared peccaries across risk conditions warrants further investigation to understand the impact of this association on the post-release success of this and other species.

Third-party conflict interventions are kin biased in captive white-lipped peccaries (Mammalia, Tayassuidae).

Third-party interventions may regulate conflicts to reduce aggression and promote cohesion amongst group members, but are rarely documented in ungulates. The white-lipped peccary (Tayassu pecari) lives in mixed-sex herds of hundreds of individuals in Neotropical forests, which are likely to benefit from mechanisms that sustain social cohesiveness. We examined third-party conflict interventions between individuals in captive groups of white-lipped peccaries. During a period of 60 days, we recorded agonistic interactions and occurrences of third-party conflict interventions, and estimated the genetic relatedness between the individuals involved using multilocus microsatellite genotypes. Most third-party conflict interventions were by the dominant male of each group, resulting in conflict termination 100% of the time. Our results also revealed that white-lipped peccaries favour their closest relatives and that individuals showed lower levels of aggression towards kin than to non-kin, and interventions on behalf of kin were more frequent than on behalf of non-kin. Our findings support the idea that genetic relatedness is fundamental in both social structure and third-party conflict interventions in this species, allowing us to suggest that kin selection could have a key role in the evolution of social behaviour of white-lipped peccaries.

Temperament, Plasticity, and Emotions in Defensive Behaviour of Paca (Mammalia, Hystricognatha).

Within a species, some individuals are better able to cope with threatening environments than others. Paca (Cuniculus paca) appear resilient to over-hunting by humans, which may be related to the behavioural plasticity shown by this species. To investigate this, we submitted captive pacas to temperament tests designed to assess individual responses to short challenges and judgement bias tests (JBT) to evaluate individuals' affective states. Results indicated across-time and context stability in closely correlated "agitated", "fearful" and "tense" responses; this temperament dimension was labelled "restless". Individual "restless" scores predicted responses to novelty, although not to simulated chasing and capture by humans in a separate modified defence test battery (MDTB). Restless animals were more likely to show a greater proportion of positive responses to an ambiguous cue during JBT after the MDTB. Plasticity in defensive behaviour was inferred from changes in behavioural responses and apparently rapid adaptation to challenge in the different phases of the MDTB. The results indicate that both temperament and behavioural plasticity may play a role in influencing paca responses to risky situations. Therefore, our study highlights the importance of understanding the role of individual temperament traits and behavioural plasticity in order to better interpret the animals' conservation status and vulnerabilities.

Individual behavioral differences and health of golden-headed lion tamarins (Leontopithecus chrysomelas).

Individual behavioral differences may influence how animals cope with altered environments. Depending on their behavioral traits, individuals may thus vary in how their health is affected by environmental conditions. We investigated the relationship between individual behavior of free-living golden-headed lion tamarins (Leontopithecus chrysomelas) responding to a novel object (to assess exploration-avoidance), and their habitat use and health status (endoparasitism; clinical measures: biometric data, heart rate, respiratory frequency, and temperature; fecal glucocorticoid metabolites). As parasite transmission can be affected by individual variation in social contact and social grooming, we also evaluated whether more sociable individuals show higher endoparasite loads compared with less sociable animals. Four groups living in landscapes with different levels of human disturbance were investigated: two in degraded forest fragments in an agricultural matrix (DFAM-higher disturbance), and two in a cocoa agroforestry system (cabruca-lower disturbance) in the Atlantic forest of South Bahia, Brazil. Using a subjective ratings approach, highly correlated adjective descriptors were combined to produce z-score ratings of one derived variable ("confidence"), which was selected to characterize the tamarins' exploration/avoidance responses during a novel object test. The higher the confidence score, the longer female tamarins spent foraging for prey independent of landscape, and the greater their body mass independent of sex and landscape. Only DFAM individuals showed intestinal parasite infection. Endoparasite loads were positively correlated with the number of grooming partners, suggesting an association between social grooming and transmission (more groomers = more endoparasites). Individual behavior, including in a test situation, may thus have some predictive value for behavior in a free-living context, and for its health consequences.

Use of the ACP® and BTS extenders for cooling at 15°C white-lipped peccary (Tayassu pecari) semen / Uso dos diluidores ACP® e BTS para refrigeração a 15°C de sêmen de queixada (Tayassu pecari)

Knowledge about reproduction of white-lipped peccary is of great importance to assist with the conservation of this species and enable its rational use in captivity. This study aimed to evaluate the effect of ACP-103®, ACP-116® and BTS semen extenders on sperm viability during cooling of Tayassu pecari semen. Five ejaculates from four adult males were chilled. The animals were submitted to the protocols of sedation and anesthesia for semen collection by the electroejaculation method. After collection, the semen was macro- and microscopically assessed and diluted to reach 35x106 spermatozoa/mL in each of the three different extenders tested. The fresh-extended semen was packed in a BotuFLEX® thermal box to keep samples at 15°C for 24 hours. After cooling, the following semen parameters were analyzed: sperm motility, functional and structural integrity of sperm membranes, mitochondrial activity, chromatin condensation, and the thermoresistance test was performed. The parameters sperm motility, structural and functional integrity of sperm membranes, mitochondrial activity, and chromatin condensation were preserved after use of the extenders tested, and were similar to those of in natura semen (p>0.05). Curvilinear velocity (VCL) (p<0.05) was the only parameter with reduced values after cooling regardless of the extender used. The percentage of sperm with normal morphology was greater in samples cooled using the BTS extender (p<0.05). The ACP-103®, ACP-116® and BTS extenders can be used for the cooling and preservation of white-lipped peccary semen at 15°C for 24 hours.(AU)

Para auxiliar na conservação da espécie e permitir o uso racional do queixada em cativeiro é de grande importância o conhecimento sobre a reprodução da espécie. Objetivou-se avaliar o efeito dos diluidores de sêmen ACP-103®, ACP-116® e BTS na viabilidade espermática durante a refrigeração do sêmen do Tayassu pecari. Foram refrigerados cinco ejaculados provenientes de quatro machos adultos. Os animais foram contidos com auxílio de puçá e submetidos ao protocolo de sedação e anestesia para realização da coleta de sêmen pelo método da eletroejaculação. Depois da coleta, o sêmen foi avaliado macro e microscopicamente e diluído para atingir 35x106 espermatozoides/mL em cada um dos três diferentes diluidores testados. O sêmen diluído foi acondicionado em caixa térmica BotuFLEX® para manter as amostras a 15°C por um período de 24 horas. Depois da refrigeração, os espermatozoides foram avaliados quanto aos parâmetros de movimento espermático, integridade funcional e estrutural das membranas espermáticas, atividade mitocondrial, condensação da cromatina e teste de termorresistência. Os diluidores testados preservaram as características cinéticas, a integridade estrutural e funcional das membranas espermáticas, a atividade mitocondrial e a condensação da cromatina semelhante ao sêmen in natura (P>0,05). O único parâmetro que reduziu com o processo de refrigeração independente do diluidor utilizado foi a Velocidade Curvilinear (VCL) (P<0,05). Foi observado aumento do percentual de espermatozoides morfologicamente normais nas amostras refrigeradas em BTS (P<0,05). Os diluidores ACP-103®, ACP-116® e BTS podem refrigerar e conservar o sêmen de queixada a 15°C por 24 horas.(AU)

Effect of different feeding regimes on cecotrophy behavior and retention of solute and particle markers in the digestive tract of paca (Cuniculus paca).

Many small herbivores practice cecotrophy - the ingestion of special feces enriched in microbial protein by colonic separation mechanisms (CSM). In digesta passage experiments, secondary marker excretion peaks in feces are considered indicative of marker-reingestion via cecotrophy, but corroboration by behavioral observation was lacking so far. The paca (Cuniculus paca), a Neotropical hystricomorph rodent, produces two different kinds of feces (hard and soft) and practices cecotrophy either directly (from the anus) or indirectly (from a pile of defecated feces, mostly when hard and soft feces are defecated together). To investigate effects of diet on cecotrophy, we monitored cecotrophy behavior and digesta passage marker excretion of solute and particle markers in four adult pacas, at constant food intake, on four diets varying in protein and fiber content. Marker excretion patterns suggested a 'mucus-trap' CSM typical for hystricomorph rodents, and showed secondary peaks of a similar time lag after cecotrophy as the primary marker peak after marker feeding. However, not every cecotrophy event was followed by a secondary marker peak. On higher fiber/lower protein diets, the number of cecotrophy bouts, the duration of cecotrophy, the number of secondary marker peaks and the difference between solute and particle marker retention increased, whereas the proportion of indirect cecotrophy decreased, indicating a higher degree of digesta phase separation on these diets. Compared to hard feces, soft feces were particularly enriched in solute marker concentration. Cecotrophy depends on a CSM that varies in its efficiency with the nutrient composition of the diet.

Capybara meat: An extraordinary resource for food security in South America.

The available information on capybara (Hydrochoerus hydrochaeris) meat, an important resource for the subsistence of many traditional communities in several South American countries, is reviewed. Some features of the species, such as an herbivorous diet, high prolificacy, rapid growth rate, tameness, and social behaviour, which allow its commercial use through harvesting in Venezuela and farming in Brazil, where commercial hunting is not allowed, is discussed. Key characteristics of capybara meat, is low saturated fat and cholesterol content. Discussions about management and handling practices regarding animal welfare and capybara meat quality are also highlighted. After commenting on ethical, political, and economic implications of wildlife use it is concluded that capybara meat has an extraordinary potential to satisfy the growing demand for healthy and high-quality protein of animal origin for the subsistence of many people in the Neotropics.

Direct and indirect caecotrophy behaviour in paca (Cuniculus paca).

The colonic separation mechanism in lagomorphs and some rodents, associated with caecotrophy, serves to retain microbial protein. As tropical fruits have low protein concentrations, caecotrophy could be an important microbial protein source in frugivorous rodents such as the paca (Cuniculus paca). Due to conflicting reports on the occurrence of caecotrophy in this species, we obtained digestive tracts of three adult animals and observed the behaviour of four specimens maintained on a diet of a pelleted feed (P) and a supplemental mix of fruits and sweet potato (S, a source of structural fibre). In a Latin square design, P and S were both offered either in the morning (M) or in the afternoon (A), or with one item in the morning and the other in the afternoon (SP or PS). The paca's proximal colon is characterized by a distinct furrow typical for the colonic separation mechanism of hystricomorph rodents. Caecotrophy, both "direct" (from the anus) and "indirect" (from a pile of defecated faeces), was a regular component of the paca's behavioural repertoire, and caecotrophs contained more nitrogen and less fibre than hard faeces. Higher food intake led to less overall caecotrophy. With afternoon feeding of S, the onset of caecotrophy was delayed and the proportion of indirect caecotrophy increased, with hard faeces and caecotrophs often defecated together. No indirect caecotrophy occurred on treatment M. The results suggest that the time available after ingestion of structural fibre determines the efficiency of the colonic mechanism for the separation of hard faeces and caecotrophs.

Vocal complexity and sociality in spotted paca (Cuniculus paca).

The evolution of sociality is related to many ecological factors that act on animals as selective forces, thus driving the formation of groups. Group size will depend on the payoffs of group living. The Social Complexity Hypothesis for Communication (SCHC) predicts that increases in group size will be related to increases in the complexity of the communication among individuals. This hypothesis, which was confirmed in some mammal societies, may be useful to trace sociality in the spotted paca (Cuniculus paca), a Neotropical caviomorph rodent reported as solitary. There are, however, sightings of groups in the wild, and farmers easily form groups of spotted paca in captivity. Thus, we aimed to describe the acoustic repertoire of captive spotted paca to test the SCHC and to obtain insights about the sociability of this species. Moreover, we aimed to verify the relationship between group size and acoustic repertoire size of caviomorph rodents, to better understand the evolution of sociality in this taxon. We predicted that spotted paca should display a complex acoustic repertoire, given their social behavior in captivity and group sightings in the wild. We also predicted that in caviomorph species the group size would increase with acoustic repertoire, supporting the SCHC. We performed a Linear Discriminant Analysis (LDA) based on acoustic parameters of the vocalizations recorded. In addition, we applied an independent contrasts approach to investigate sociality in spotted paca following the social complexity hypothesis, independent of phylogeny. Our analysis showed that the spotted paca's acoustic repertoire contains seven vocal types and one mechanical signal. The broad acoustic repertoire of the spotted paca might have evolved given the species' ability to live in groups. The relationship between group size and the size of the acoustic repertoires of caviomorph species was confirmed, providing additional support for the SCHC in yet another group of diverse mammals-caviomorph rodents.

Protein requirements of collared peccary (Pecari tajacu).

A nitrogen (N) balance digestion trial was conducted to determine the protein requirement of collared peccaries (Pecari tajacu). In a 4 × 4 Latin square design, four captive adult male peccaries were fed four isoenergy diets containing four different levels of N (11.7, 16.3, 22.8, and 26.7 g N/kg of dry matter-DM). After 15 days of adaptation, a total collection of feces and urine was carried out for five consecutive days. Regression analyses between N intake and N in feces and urine allowed to calculate the metabolic fecal nitrogen (MFN = 2.3 g N/kg of dry matter intake-DMI) and daily endogenous urinary N (EUN = 185 mg N/kg0.75). Likewise, by regression analyses between consumption of nitrogen and the nitrogen balance (NB = N ingested - N excreted, mg N/kg0.75), a daily requirement of 514 mg N/kg0.75 was calculated. Therefore, if food intake is unrestricted, collared peccaries require a minimum in their diet of about 5.4% crude protein on DM basis. These values are almost as low as those found for browsing and frugivorous wild ruminants, which reinforce the proposition that peccaries' digestive physiology is nearer to that of domestic and wild ruminants than domestic pigs. This relatively low protein requirement of collared peccary and its great ability to digest protein reveal the relevance of the forestomach for the species on nitrogen/protein metabolism and allow the use of diets with lower crude protein levels than the commercial ones used for the domestic pig, which reduces feed costs.

Flexibility in the social behavior of captive female capybaras (Mammalia, Rodentia).

Capybara (Hydrochoerus hydrochaeris) lives in stable groups composed of adult males and females with their young. The species shows flexibility in social organization in response to short-term environmental changes, but apparently does not show flexibility in social behavior. To gain insights into mechanisms underlying changes in social relationships, we analyzed the social dominance hierarchy of five captive capybara groups, composed of four to 13 adult females kept in outdoor paddocks ranging from 400 to 4500m2. In addition, we evaluated the effects of group size and space allowance on two complementary properties of social structure: linearity and steepness. Captive female capybaras exhibit a linear social dominance hierarchy. There was also more predictability in the dominance success- hierarchical steepness - in the dominance hierarchy with a decrease in the space per individual. This variability in response to changing circumstances shows flexibility in capybara's social behavior.

The Role of Grunt Calls in the Social Dominance Hierarchy of the White-Lipped Peccary (Mammalia, Tayassuidae).

Grunt-like calls are present in the vocal repertoire of many group-living mammals and seem to facilitate social interactions between lower and higher-ranking members. The white-lipped peccary (Tayassu pecari) lives in stable hierarchical mixed-sex groups and like non-human primates, usually emits grunt-like calls following aggressive interactions, mainly during feeding contexts. We investigated the possible functions of peccaries' grunt-like calls and their relationship to the individuals' social rank, identity, and sexual dimorphism. We observed that low-ranking individuals emitted grunt-like calls more often than high-ranking ones, and that the alpha male never emitted this vocalization. Moreover, the mean minimum frequency of grunt-like calls decreased as the peccary's rank increased. The findings revealed differences among individual grunts, but the low accuracy of cross-validation (16%) suggests that individual recognition in peccaries may be less important than an honest signal of individual social status. In addition, the absence of differences in the acoustic parameters of grunt-like calls between males and females points to the lack of sexual dimorphism in this species. We verified that after hearing grunt calls, dominant opponents were more likely to cease attacking a victim, or at least delay the continuation of conflict, probably decreasing the severity of agonistic interactions. Our findings are particularly important to improve the current understanding of the role of grunt-like calls in herd-living mammals with linear dominant hierarchies, and strongly suggest that they are involved in the maintenance of herd social stability and cohesion.

Protein requirements of finishing paca (Cuniculus paca).

We conducted a nitrogen balance digestion trial to determine the crude protein requirements of paca (Cuniculus paca) during the last growth phase. In a 4 × 4 Latin square design, four young captive male pacas, aged 5 months, were fed four isoenergetic diets containing four different levels of nitrogen (N) (11.3, 16.6, 21.4, and 26.6 g N/kg of dry matter). After 15 days of adaptation, we collected all feces and urine for five consecutive days. By regression analysis between N intake and N in feces and urine, the metabolic fecal nitrogen (MFN = 4.2 g/kg of dry matter intake) and daily endogenous urinary N (EUN = 91.6 mg/kg(0.75)) were determined. Likewise, by regression analyses between nitrogen intake and nitrogen retention [NR = N intake-(fecal N + urine N)], we estimated the daily requirement of 280.5 mg N/kg(0.75). Therefore, a minimum of 55 g crude protein per kilogram dry matter and 13 MJ/kg of digestible energy are required by finishing paca on unrestricted diets. Such values are similar to those of other wild frugivores and below those of growing rabbits. The data confirm that farmers overfeed protein, and similar growth can be more economically achieved on lower protein diets.