Infestation of arboreal nests of coatis by triatomine species,vectors of Trypanosoma cruzi,in a large Neotropical wetland

The coati (Nasua nasua, Carnivora) is a medium‐sized mammal common in the Pantanal of Brazil. Unlike most mammals, coatis construct arboreal nests used for resting and reproduction. In this region, the coati is an important host of Trypanosoma cruzi, the causative agent of Chagas disease. There are two possible routes through coatis can be infected by T. cruzi: the oral route or the vectorial route. However, the relative importance of each of these routes in the infection of coatis and its role in the sylvatic cycle of the parasite are unknown. Our objectives were to investigate: (i) whether coati nests were infested by triatomine bugs, (ii) what species were frequent in the nests, (iii) whether the triatomines in nests were infected by T. cruzi, and (iv) what were the food resources of these triatomines. Eight of the 24 nests sampled were infested with triatomines, a total of 37 specimens of at least two species (Rhodnius stali and Triatoma sordida). In one nest, R. stali and T. sordida co‐occurred and both fed on multiple resources, including coatis. This is the first report of triatomines occurring in arboreal nests of coatis. The co‐occurrence of two different genera of triatomine vectors and coatis within the limited space of the coati nests provide multiple opportunities for the exchange of the protozoan parasite through both the vectorial and oral transmission routes.     

Do Collared Peccaries Negatively Impact Understory Insectivorous Rain Forest Birds Indirectly Via Lianas and Vines?

Tropical rain forest understory insectivorous birds are declining, even in large forest reserves, yet the mechanisms remain unclear. Abundant large mammals can reshape forest structure, which degrades foraging microhabitat. We used six sites in Nicaragua, Costa Rica, and Panama with varying collared peccary (Pecari tajacu) density to test three linked hypotheses: (1) locally declining understory insectivores forage preferentially in liana tangles; (2) vine and liana density, cover, and frequency of dense tangles are lower in the presence of abundant collared peccaries; and consequently (3) abundant collared peccaries are associated with reduced understory insectivorous bird abundance. Three insectivores that declined at La Selva preferentially foraged in liana tangles: Checker‐throated Antwren (Epinecrophylla fulviventris), Dot‐winged Antwren (Microrhopias quixensis), and Ruddy‐tailed Flycatcher (Terenotriccus erythrurus). Vine density, liana cover, liana tangle frequency, and forest cover were lower in the presence of collared peccaries relative to experimental mammal exclosures, with the greatest differences at La Selva Biological Station, Costa Rica. Across sites, five of seven vine and liana measures showed negative, curvilinear relationships with peccary densities. Vine and liana measures peaked at sites with intermediate peccary density, and were low at La Selva. Structural equation models suggest negative indirect effects of the collared peccaries on focal bird densities, mediated by vine and liana density, cover, or tangle frequency. Forest area and rainfall affected both lianas and birds, but collared peccaries also contributed to the reduced abundance of understory insectivores. Indirect effects such as that suggested here may occur even in large, protected forest reserves where large mammal communities are changing.     

Movement and resource use by a group of <Emphasis Type="Italic">Alouatta pigra</Emphasis> in a forest fragment in Balancán,México

Uncommonly observed behaviors were systematically recorded in a troop (n = 9 individuals) of black howler monkeys (Alouatta pigra) inhabiting a small forest fragment (1.7 ha) in Leona Vicario, Balancán, Tabasco, Mexico. Between February 2002 and January 2003 (n = 499 h), we observed behaviors such as ground travel (85 occasions, total = 269 min/10.8% of total locomotion time), ground foraging (eight occasions, total = 50 min/0.84% of total feeding time) and drinking water pooled in tree holes (20 times, total = 93 min/0.31% of total activity time). Total time (412 min) for these non-resting behaviors (feeding and locomotion on the ground) is almost equivalent to time devoted to social activities (420 min). These behaviors indicate that howler monkeys may be responding to pressures imposed by the small size of the fragment by adopting diverse strategies to cover their basic nutritional needs in this environment. They accomplish this while exposing themselves to potential predation by coyotes (Canis latrans), as was observed once during the study. It is likely that these behaviors are occurring at an increasing rate among monkeys in fragmented landscapes.     

Intraspecific aggression results in death of a collared peccary

An adult male collared peccary (Dicotyles tajacu) caught from the wild was released into an outdoor enclosure containing 12 other wild adult peccaries. The introduced male died of severe infection as a result of scrotal wounds inflicted by resident peccaries.     

Interaction Between Capuchins and Coatis: Nonagonistic Behaviors and Lack of Predation

We compare the nature of capuchin-coati interactions by Cebus apella in 2 populations under semifree-ranging and wild conditions. We report a similar pattern of interaction at both sites, in spite of their ecological differences. Most frequent capuchin behaviors toward coatis were agonistic, but we noted no predation. Contrarily, the monkeys also exhibited nonagonistic behaviors, such as play and grooming. As tufted capuchins predate other mammalian species, and as the subjects were aggressive towards competitor species, showing their belligerent temperament, we believe the lack of predation can be attributed to 2 different ecological contigencies – the absence of coati pups in a period of food shortage, and the cost of dealing with a dangerous adult coati where other rich resources were available–and also, perhaps, to different traditions in capuchin behavior towards coatis, established via intraspecific social learning.     

Bluffing in the forest: Neotropical Neomorphus ground‐cuckoos and peccaries in a possible case of acoustic mimicry

Acoustic communication is particularly important in environments such as dense tropical forests, where the dim light constrains the efficacy of visual signals. In these environments, complex species interactions could promote the evolution of acoustic signals and result in intriguing patterns of mimicry and convergence. In the Neotropical region, Neomorphus ground‐cuckoos frequently associate with herds of collared peccaries and white‐lipped peccaries. Bill clacking behavior in ground‐cuckoos closely resembles the sound of teeth clacking in peccaries and these acoustic signals are used in agonistic and foraging contexts in both species. Here we demonstrate that the acoustic characteristics of bill clacking in ground‐cuckoos are more similar to teeth clacking of peccaries than to bill clacking of the more closely related Geococcyx roadrunner. We propose that two hypotheses may explain the evolution of the clacking behavior in these taxa. First, because peccaries are known to successfully ward off attacks from large predators to defend their herds, mimicking their clacking can deceive predators, either by triggering clacking from nearby peccaries, or making it appear to the predators that peccaries are present when they are not. Second, ground‐cuckoos and peccaries could mutually benefit from the use of similar signals to alert each other of the presence of predators. In this context, ground‐cuckoos could serve as sentinels while peccaries could confer protection. We also discuss alternative explanations for this striking acoustic resemblance. Ground‐cuckoos and peccaries provide an interesting opportunity to study how an ecological association could foster the evolution of acoustic mimicry.     

Mandible/basihyal relationships in red howler monkeys (Alouatta seniculus): A craniometrical approach

The morphological relationships between the cranium and basihyal of red howler monkeys (Alouatta seniculus) were analyzed based on measurements of 36 cranial and 3 basihyal dimensions and observations of the female specimen in spirits. In this study, 115 crania from 111 red howler monkeys and 4 mantled howler monkeys (Alouatta palliata) were used. The analyses from the standpoints of the correlation coefficients, principal component analysis, discriminant function analysis, age changes and sex differences were performed and the following results were obtained: (1) The cranial measurements closely related to the basihyal measurements were mandibular length, occipital breadth, facial length, ramus height, cranial base length, bigonial breadth and pr-i length. (2) Age changes for the mandibular measurements in males of red howler monkeys were remarkable, and, in particular, the development of the gonion toward posterior and lateral directions were characteristic. (3) The largest sex differences were found in the mandibular measurements of red howler monkeys among the Anthropoidea of seven genera compared. (4) The existence of a “cline” in the cranial measurements of the red howler monkey was recognized. (5) The inter-species differences in the crania between the red howler monkey and mantled howler monkey are obvious, metrically and non-metrically. Based on the results mentioned above, the morphological relationships between the mandible and basihyal in the red howler monkey are discussed.     

Complementary roles of two resilient neotropical mammalian seed dispersers

Capuchin monkeys (Cebus spp. and Sapajus spp.) and coatis (Nasua spp.) coexist in most neotropical forests, including small forest remnants. Both capuchins and coatis eat fruit and disperse seeds, but little is known about whether their roles in seed dispersal are redundant or complementary. We compiled 49 studies from the literature on feeding by capuchins and/or coatis, of which 19 were comprehensive enough for our analyses. We determined the relative importance of fruit eating to each species and compared their diets. Additionally, we analysed the structure of three fruit–frugivore networks built with both animal groups and the fruits they eat and evaluated whether fruit traits influenced the network topology. Fruits represented the largest part of capuchin and coati diets, even though coatis have been known for their opportunistic and generalist diets. Capuchins and coatis also exhibited similar general diet parameters (niche breadth and trophic diversity). The three networks exhibited high connectance values and variable niche overlap. A Multiple Correspondence Analysis, failed to detect any trait or trait combination related to food use. In conclusion, capuchins and coatis both have generalist diets; they feed on many different species of fruits and exhibit important complementarity as seed dispersers. Both are likely to be particularly important seed dispersers in disturbed and fragmented forests.     

Co-Infection and Wild Animal Health: Effects of Trypanosomatids and Gastrointestinal Parasites on Coatis of the Brazilian Pantanal

Wild animals are infected by diverse parasites, but how they influence host health is poorly understood. We examined the relationship of trypanosomatids and gastrointestinal parasites with health of wild brown-nosed coatis (Nasua nasua) from the Brazilian Pantanal. We used coati body condition and hematological parameters as response variables in linear models that were compared using an information theoretic approach. Predictors were high/low parasitemias by Trypanosoma cruzi and T. evansi, and indices representing the abundance of distinct groups of gastrointestinal parasites. We also analyzed how host health changed with host sex and reproductive seasonality. Hemoparasites was best related to coati body condition and hematological indices, whereas abundance of gastrointestinal parasites was relatively less associated with coati health. Additionally, some associations were best predicted by models that incorporated reproductive seasonality and host sex. Overall, we observed a lower health condition during the breeding season, when coatis are under reproductive stress and may be less able to handle infection. In addition, females seem to handle infection better than males. Body condition was lower in coatis with high parasitemias of T. evansi, especially during the reproductive season. Total red blood cell counts, packed cell volume, platelets and eosinophils were also lower in animals with high T. evansi parasitemias. Total white blood cell counts and mature neutrophils were lower in animals with high parasitemias for both Trypanosoma species, with neutrophils decreasing mainly during the reproductive season. Overall, decreases in hematological parameters of females with T. evansi high parasitemias were less evident. For T. cruzi, monocytes decreased in individuals with high parasitemias. High abundances of microfilariae in the bloodstream, and cestode eggs and coccidian oocysts in feces were also associated with coati blood parameters. This study shows the potential value of examining hematological parameters as an approach to better understand the ecological relevance of parasite-host interactions.     

Tool use by a red howler monkey (Alouatta seniculus) towards a two-toed sloth (Choloepus didactylus)

Among New World monkeys, spontaneous tool use and object manipulation are commonly descirbed inCebus species only. We report here an occurrence of tool manipulation by a wild male red howler monkey (Alouatta seniculus), observed using a stick to softly but repeatedly hit a two toed sloth (Choloepus didactylus) resting in the same tree. The ecological context of this unusual behavior for this quiet species generally showing very little manipulative propensity is discussed.     

Diet Overlap and Foraging Activity between Feral Pigs and Native Peccaries in the Pantanal

Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu) with the invasive feral pig (Sus scrofa) in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods.     

Male parental behavior in black howler monkeys (Alouatta palliata pigra) in Belize and Guatemala

Male parental behavior was observed in black howler monkeys (Alouatta palliata pigra) in Belize and Guatemala from December 1978 to March 1979, with the objective of relating parental behavior to the prevailing monogamous group structure. The results revealed that male parental behavior inAlouatta palliata pigra agrees in some respects with reports from the literature on polygamous and polygynous species ofAlouatta, while in other respects the situation more closely resembles that in monogamous species of non-human primates. Considerable inter-individual variability in male-infant interactions prevailed among the study groups. Male parental behavior in the Belize groups became more prominent with increasing age of an infant.     

Collared peccary (Pecari tajacu) behavioral reactions toward a dead member of the herd

Humans, elephants, chimpanzees, and cetaceans show concern with the death of other members of their species and respond to death in particular ways. Science considers that these species are exceptions and that other mammal species show little or no reaction to the dead bodies of individuals of their species. Collared peccaries (Pecari tajacu; Tayassuidae) are social animals that live in groups of 5–50 individuals maintaining close and complex social relationships. The collared peccary occupies many different environments and it is widely distributed from the south of North America to the north of Argentina. Their behavior is well studied, but we know little about their behavior toward the dead. We directly observed and filmed with a camera trap the reactions of a five‐member herd of collared peccaries to the death of a herd member. We worked on a suburban forested area in the mountains of central Arizona. We found that the herd visited and spent time with the dead body for 10 days after the peccary died. The frequency of the visits declined until the cadaver was consumed by coyotes. Most of the videos showed two individuals visited the dead animal (44%), solitary records were also frequent (39%) and only 4% of the videos recorded three peccaries. Visits were more frequent during the night (64%). Peccaries do react to the death of a herd member by behaving in particular ways. Reactions include pushing at the dead individual, staring at it, biting it, and trying to pick it up by putting their snout under the corpse and pushing it up, and defending it from coyotes, among others. These levels of behavioral complexity for peccaries are beyond those known so far. The behaviors of this herd of peccaries resemble those of humans, cetaceans, chimpanzees, and elephants and show that these groups are not the only ones that react to death.     

Timing of births in sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus).

We monitored the birth patterns of sympatric brown howler monkeys (Alouatta fusca clamitans) and northern muriquis (Brachyteles arachnoides hypoxanthus) during a 4‐yr period from October 1996 to August 2000 at the Estação Biológica de Caratinga, Minas Gerais, Brazil. Brown howler monkey births (n = 34) occurred throughout the year, and birth frequencies did not differ between rainy and dry season months. The aseasonal birth patterns of the howler monkeys differed significantly from the dry season concentration and dry month peak in muriqui births (n = 23). We found no effects of infant sex or the number of females on interbirth intervals (IBIs) in our 10 howler monkey study troops. IBIs of brown howler monkeys averaged 21.2 ± 2.5 mo (n = 8, median = 21.0 mo), and were significantly shorter following dry season births than rainy season births. Their IBIs and yearling survivorship (74%) were similar to those reported for other species of howler monkeys, but yearling survivorship was much lower than that of muriquis (94%), whose IBIs were more than 12 mo longer than those of the howler monkeys. Our study extends comparative knowledge of birth patterns in Alouatta to a poorly known species, and provides insights into the different ways in which diet and life history may affect the timing of births in large‐bodied platyrrhines under the same seasonal ecological conditions. Am. J. Primatol. 55:87–100, 2001. © 2001 Wiley‐Liss, Inc.     

Survey of the black howler monkey,<Emphasis Type="Italic">Alouatta pigra</Emphasis>, population at the Mayan site of Palenque,Chiapas, Mexico

A survey of the population of the black howler monkey (Alouatta pigra) present at the Mayan site of Palenque was conducted during 2000. A total of 911 man/hours, spread over 112 days were spent surveying the 600 ha area of pristine forest at the site for howler troops. We detected the presence of 136 individuals of which 131 were members of 20 troops, the rest were 3 solitary adult males and 2 adult males travelling as a pair. Ecological density was estimated at 23 individuals/km². Mean troop size was 7.0 individuals and it ranged from 2–12 individuals; 60% of the troops were multimale. All sighting of howler monkeys were in evergreen rain forest and 75% were in trees ≥20 m in height. The reported densities and mean troop size are higher than those reported for the species in Guatemala and in central Quintana Roo, Mexico. The vegetation of the forest contains tree species reported to be used by species ofAlouatta in the Moraceae, Sapotaceae, Leguminosae, and Lauraceae plant families. Protection of a large perimeter area (ca 1700 ha) around the archeological site by the Mexican government ensures the conservation of the forest and of the black howler monkey population present at the site.     

Seed predation ofCariniana estrellensis (Lecythidaceae) by black howler monkeys,Alouatta caraya

Seed predation by howler monkeys is poorly documented. Here we report the seed predation onCariniana estrellensis (Lecythidaceae) fruits by the black howler monkeyAlouatta caraya in south-east Brazil during an intense dry season. This observation suggests that even non-specialized seed predators such as howlers can use seeds in critical periods of dry season.     

Diet and activity in black howler monkeys (<Emphasis Type="Italic">Alouatta pigra</Emphasis>) in southern Belize: does degree of frugivory influence activity level?

This study reports on the diet and activity budgets of Central American black howling monkeys (Alouatta pigra) at Monkey River, Belize. This is a previously unstudied population, close to the southern boundary of the species range, and it provides comparative data on A. pigra from a new study site. Both diet and activity are within the ranges reported for other A.pigra sites and for mantled howlers (A. palliata). No age-sex differences could be discerned in either diet or activity, though monthly variation was apparent. The monkeys switch from consuming leaves 86% of the time in January to March to consuming 67% fruit in April to July. This difference was statistically significant, and provided the opportunity to compare activity levels of the monkeys over two dietary periods, one characterized primarily by folivory, the other by frugivory. Howlers are often seen as a relatively inactive species, something that is associated with a low quality, folivorous diet. However, A. pigra have been described as being as frugivorous as possible and as folivorous as necessary. Yet, despite the opportunistic consumption of large quantities of high-energy foods, A. pigra has been observed as conforming to the howler lifestyle, resting as much as 80% of the day. The data in this paper support both of these reports. Black howlers at Monkey River Belize are typically inactive, maintaining high levels of inactivity even during months characterized by frugivory, suggesting that diet is more flexible and varied than is behavior and calling into question the assumption that howler inactivity is due to the digestion of large quantities of leaves.     

Intraspecific, interspecific, and seasonal differences in the diet of three mid-sized carnivores in a large neotropical wetland

The diet and partitioning of food resources among mid-sized mammalian carnivores is poorly known, especially in the tropics. We evaluated the resource partitioning between Leopardus pardalis (ocelot), Cerdocyon thous (crab-eating fox), and Nasua nasua (brown-nosed coati) in the Pantanal of Brazil. Between December 2005 and February 2008, we collected data necessary to better understand interspecific, intraspecific, and seasonal variability in diet. Food habits were assessed by analysis of feces (n?=?293) collected from known individuals (n?=?128), and differences in dietary composition were evaluated through nonmetric dimensional scaling using the Jaccard similarity index. The main diet differences were observed between the specialist ocelot and the more generalist crab-eating fox and brown-nosed coati. Crab-eating foxes and brown-nosed coatis preyed on arthropods, fruits, and vertebrates whereas ocelots preyed almost entirely on vertebrates, mainly rodents and snakes. Ocelots’ consumption of snakes was the highest ever recorded, as was the extent of carnivory by brown-nosed coatis. For the crab-eating fox and the brown-nosed coati, there were large differences between the use of fruits and animal foods in the wet and dry season. Yet for both species there were no significant differences in the diets of males and females. Despite the conspicuous sexual dimorphism and spatial segregation that are typical of brown-nosed coatis, the results do not support the hypothesis that size dimorphism is primarily an adaptation to reduce intersexual competition for food. Rather, dimorphisms and patterns of space use may be more related to competition among males for access to females.     

Estimation of the retention times and distances of seed dispersed by two monkey species, Alouatta seniculus and Lagothrix lagotricha, in a Colombian forest

Isolated-bout method to estimate the retention times and dispersal distances was applied to the seed dispersal by red howler monkeys (Alouatta seniculus) and Humboldts woolly monkeys (Lagothrix lagotricha) in a lowland tropical forest at La Macarena, on the border of the Macarena and Tinigua National Parks, the Department of Meta, Colombia. Continuous observations were made on the feeding and ranging behavior of well-habituated troops of howler monkeys and woolly monkeys as well as continuous collection of monkeys feces. We selected out the isolated-bout as a feeding bout on the specific species that was only once recorded within 48 h before the seeds of that species appeared in the feces of monkeys. In that case, the seeds were strongly suggested to come from that isolated bout. Then retention times, route seed dispersal distances and direct seed dispersal distances were estimated. Howler monkeys, which are regarded as generalist herbivores, showed longer retention times and dispersal distances along monkeys route than did woolly monkeys, which are specialist frugivores. However, the direct distances that seeds were carried from the mother tree were not significantly greater for howler monkeys than for woolly monkeys. This shows that both retention time and movement patterns by the monkeys, especially the total ranging area, influence the direct distance that seeds are carried from the mother tree.     

Interspecific interaction and predator avoidance behavior in response to tayra (<Emphasis Type="Italic">Eira barbara</Emphasis>) by mantled howler monkeys (<Emphasis Type="Italic">Alouatta palliata</Emphasis>)

This paper reports the response of one howler monkey group (Alouatta palliata) to a group of potential predators, the tayra (Eira barbara). The apparently successful predator avoidance behavior of the monkeys was recorded in detail. We observed a group of four adult tayras moving around theAlouatta group displaying a species-typical aggressive behavioral pattern. The two adult females of the howler group successfully chased the tayras away by repeatedly moving closer to the mustelids and even following them until the predators moved off.