Capybara (Hydrochoerus hydrochaeris) distribution in agroecosystems: a cross-scale habitat analysis

Aim The aim of this study was to understand the spatial distribution of capybara (Hydrochoerus hydrochaeris) according to habitat attributes, using a multiscale approach based on fine‐ and broad‐scale variables in agroecosystems. Location Piracicaba river basin, south‐eastern Brazil (22°00′–23°30′ S; 45°45′–48°30′ W). Methods Potential habitats for capybara were selected in order to evaluate species presence/absence from October 2001 to December 2002. In each site, habitat attributes were sampled in the field (fine scale) and from GIS maps (broad scale) in terms of their presence or absence close to water. The variability of land cover between study sites was described by principal components analysis. Chi‐square tests were calculated for capybara presence/absence and the presence of each habitat attribute. A linear discriminant function analysis was used to describe to what extent the species’ presence could be explained by habitat attributes. Results The species presence was predominantly related to flat open areas (slope ranging from 0% to 6%) (χ² = 37.054, d.f. = 4, P < 0.001), covered by sugar cane or cultivated pasture (χ² = 84.814, d.f. = 9, P < 0.001). Terrain curvature, water meadows, aquatic vegetation, forest cover and open areas resulted in the best combination of variables, explaining 69.7% of capybara occurrence in the study sites in this river basin. Main conclusions Capybaras are widespread in the Piracicaba river basin, except in elevated areas. The spatial distribution of capybara was associated with the main types of land cover in the river basin – sugar cane plantations or pasture – both key food sources for capybara. This probably explains the species’ recent abundance in the region, since an intensive process of landscape alteration has taken place in this region owing to the expansion of agriculture in recent decades. These results may be useful in understanding the relationship between recent landscape modifications and the species’ population expansion in agroecosystems.     

Vocal signature in capybara,Hydrochoerus hydrochaeris

Social groups of capybaras are stable and cohesive. The species’ vocal communication is complex and mediates social interaction. The click call is emitted in a variety of contexts by animals from all age groups, but differs among groups; its attributed function is to keep contact among animals. To evaluate the presence of individual characteristics in the click call of capybaras, we recorded the vocalizations emitted spontaneously by six adults kept either solitary or in groups. We selected and measured the acoustic parameters of 300 click call phrases, 50 per individual. The parameters were submitted to a discriminant function analysis that revealed a classification accuracy of 76.8 %. A General Linear Model analysis revealed significant differences among the six individuals, and post hoc results showed that differences between a given pair were different from those of any other pair. The acoustic parameters that most contributed to discriminate the individual calls were click interval duration and click duration, suggesting that temporal parameters are more important than frequency parameters for individuals’ discrimination. The findings of individual characteristics in the click calls indicate that these vocalizations can be used as vocal signatures during social interactions.     

Rumen Ophryoscolecid Protozoa in the Hindgut of the Capybara (Hydrochoerus hydrochaeris)1

Rumen ophryoscolecid protozoa were observed in feces obtained from two capybara (Hydrochoerus hydrochaeris) housed at the Columbus Zoo, Columbus, Ohio. Total numbers were 58.1 times 10⁴ and 19.0 times 10⁴ per gram of wet feces in a male and female capybara, respectively. Four common rumen species of Entodinium were observed in the feces from both animals, with low numbers of Eudiplodinium maggii and Elytroplastron bubali also occurring in the male. Establishment of rumen ophryoscolecid ciliates in the intestinal tract of non-ruminant herbivores has not been reported previously.     

The Function of Click Call Emission in Capybaras (Hydrochoerus hydrochaeris)

Contact calls are used to promote cohesion among individuals that live in social groups. Capybaras are very gregarious and often vocalize. This species emits a vocalization known as a click, which has been observed during aggregating and foraging behaviors, suggesting contact or monitoring call function. We carried out a playback experiment to evaluate behavioral responses to the capybara's click call and to a bird call, used as control in ten capybaras. We compared animals' latency to respond to stimuli, the time spent in behavioral patterns, alertness, head orientation toward the sound source, and approach to the sound source. All capybaras responded to the emission of the click call playback. Most of them assumed an alert position, showed head orientation toward the sound source, and approached the sound source. They promptly reacted to the first click call emission, while few reacted to the first bird call emission, used as control. All subjects showed behavioral changes after the second emission of the click call, and some responded to the third emission. Just three individuals answered after the first control emission, while none of them responded to the second and third emission of the playback. Therefore, click call playback promotes prompt behavioral changes in capybaras, including approach to the sound source. These results indicate that this vocalization functions as a contact or monitoring call in the species.     

Vocal Repertoire of Cebus capucinus: Acoustic Structure, Context, and Usage

Researchers studying nonhuman primate vocal repertoires suggest that convergent environmental, social, and motivational factors account for intra- and interspecific vocal variation. We provide a detailed overview of the vocal repertoire of white-faced capuchins, including acoustic analyses and contextual information of vocal production and vocal usage by different age-sex classes in social interactions. The repertoire is a mixture of graded and discrete vocalizations. In addition, there is general support for structural variation in vocalizations with changes in arousal level. We also identified several combined vocalizations, which might represent variable underlying motivations. Lastly, by including data on the social contexts and production of vocalizations by different age-sex classes, we provide preliminary information about the function of vocalizations in social interactions for individuals of different rank, age, and sex. Future studies are necessary to explore the function of combined vocalizations and how the social function of vocalizations relate to their acoustic structure, because social use of vocalizations may play an important role in shaping vocal evolution.     

Behavioral observations in a capybara colony (Hydrochoerus hydrochaeris)

Capybaras (Hydrochoerus hydrochaeris), the largest living rodents, are receiving increasing interest as an economically attractive source of meat and hides in tropical America. An unmanaged capybara colony was studied in a setting adjacent to agricultural activities in Brazil. Preliminary notes were made on alarm responses to intruders, various aspects of flight behavior, and investigatory activity. The findings were mostly consistent with studies carried out by other investigators, suggesting that capybara behavior is similar from one region to another. The animals have potential for habituation to humans and are probably good candidates for domestication. Expanded commercial exploitation of capybaras could benefit their survival and welfare as well as contributing to the preservation of neotropical ecology in general.     

Vocalisation Repertoire of Female Bluefin Gurnard (Chelidonichthys kumu) in Captivity: Sound Structure,Context and Vocal Activity

Fish vocalisation is often a major component of underwater soundscapes. Therefore, interpretation of these soundscapes requires an understanding of the vocalisation characteristics of common soniferous fish species. This study of captive female bluefin gurnard, Chelidonichthys kumu, aims to formally characterise their vocalisation sounds and daily pattern of sound production. Four types of sound were produced and characterised, twice as many as previously reported in this species. These sounds fit two aural categories; grunt and growl, the mean peak frequencies for which ranged between 129 to 215 Hz. This species vocalized throughout the 24 hour period at an average rate of (18.5 ± 2.0 sounds fish^-1 h^-1) with an increase in vocalization rate at dawn and dusk. Competitive feeding did not elevate vocalisation as has been found in other gurnard species. Bluefin gurnard are common in coastal waters of New Zealand, Australia and Japan and, given their vocalization rate, are likely to be significant contributors to ambient underwater soundscape in these areas.     

Characterization of microsatellite markers from capybaras,Hydrochoerus hydrochaeris (Rodentia: Hydrochoeridae)

Fourteen microsatellite loci were isolated from capybaras (Hydrochoerus hydrochaeris), which are large, diurnal social rodents that occur in the wet savannas of South America. Five of these loci were monomorphic. The remaining nine loci were polymorphic (two to seven alleles per locus), with observed levels of heterozygosity ranging from 0.063 to 0.800 (n = 17 animals). The latter loci provide a valuable tool for assessing patterns of parentage and kinship within capybara social groups.     

The intertubular compartment morphometry in capybaras (Hydrochoerus hydrochaeris) testis

The aim of the present study was to characterize the intertubule element volume density, individual and total Leydig cells volume, Leydig cell number per testis and per gram of testis, and leydigosomatic index in adult capybaras. Eight capybaras from a commercial abattoir were utilized. The intertubular compartment volume density and the Leydig cells were 45.2 and 31.13%, respectively. The individual and total Leydig cell volumes were 8.51 and 2169.41 x 10(-12) mL, respectively. The Leydig cell number per testis was 3.8 billion and the Leydig cell number per gram of testis was 126 million. The leydigosomatic index was 0.037%. In conclusion, this study shows that capybaras have one of the greatest individual and total Leydig cell volume and Leydig cell volume density, and that the Leydig cell number per gram of testis is at least double the mean for mammals previously investigated in its order.     

Acute phase protein response in the capybara (Hydrochoerus hydrochaeris)

We evaluated the acute phase protein response in capybaras (Hydrochoerus hydrochaeris). Three animal groups were used: 1) healthy animals (n=30), 2) a group in which experimental inflammation with turpentine was induced (n=6), and 3) a group affected with sarcoptic scabies (n=14) in which 10 animals were treated with ivermectin. Haptoglobin (Hp), acid-soluble glycoprotein (ASG) and albumin were analyzed in all animals. In those treated with turpentine, Hp reached its maximum value at 2 wk with a 2.7-fold increase, whereas ASG increased 1.75-fold and albumin decreased 0.87-fold 1 wk after the induction of inflammation. Capybaras affected with sarcoptic scabies presented increases in Hp and ASG of 4.98- and 3.18-fold, respectively, and a 0.87-fold decrease in albumin, compared with healthy animals. Haptoglobin and ASG can be considered as moderate, positive acute phase proteins in capybaras because they showed less than 10-fold increases after an inflammatory process and reached their peak concentrations 1 wk after the induction of inflammation. Conversely, albumin can be considered a negative acute phase protein in capybaras because it showed a reduction in concentration after inflammatory stimulus.     

Intestinal helminths of capybaras, Hydrochoerus hydrochaeris, from Venezuela

Quantitative parameters of intestinal helminth species and their potential relations to host characteristics in a population of capybaras (Hydrochoerus hydrochaeris) from Venezuela are reported for the first time. The intestines of 40 capybaras were collected during the 1992-annual harvest at Hato El Cedral. Six helminth species were found: 2 cestodes (Monoecocestus macrobursatum, M. hagmanni), 2 nematodes (Viannella hydrochoeri, Protozoophaga obesa), and 2 trematodes (Hippocrepis hippocrepis, Taxorchis schistocotyle). This is the first report for M. macrobursatum in Venezuela. Helminth abundance did not differ between sexes or age classes. Although patterns of distribution for all helminth species were overdispersed, the high prevalence found for all species (over 70%) and the high abundance observed for nematodes made it difficult to assess the effect that these helminths may produce on capybaras. Nevertheless, the negative associations found between the body condition of capybaras and helminth intensity for M. macrobursatum and V. hydrochoeri, might be pointing out potential host population regulatory role for these parasites which require further research.     

Evaluation of three immobilization combinations in the capybara (Hydrochoerus hydrochaeris)

Capybaras (Hydrochoerus hydrochaeris) are the world's largest rodent. Owing to its uniqueness, 50 AZA institutions in North America display this species. As shown by a survey, no standard anesthetic protocol has been developed for this species. As a part of an ongoing behavioral study in Venezuela, capybaras were surgically implanted with radio transmitters. Animals were randomly assigned to one of the three immobilization protocols: (1) Tiletamine HCl/Zolazepam HCl, (2) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl, and (3) Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. The protocol recommended for minimally invasive procedures when inhalant anesthetics are unavailable is a combination of Tiletamine HCl/Zolazepam HCl/Medetomidine HCl/Butorphanol tartrate. This is based on ease of administration, volume, onset of action, depth of anesthetic achieved, reversibility, safety, and costs. Zoo Biol 29:59–67, 2010. © 2009 Wiley‐Liss, Inc.     

Assessment of capybara (Hydrochoerus hydrochaeris) populations in the wetlands of Corrientes,Argentina

Ten sampling sites were selected to represent six distinct habitat types used by capybaras (clean lagoons, dirty lagoons, cutwaters, fens and marshes, gallery forests, and erosion ditches). The sites were sampled during winter (July and August); densities were expressed as number of capybaras per linear km of shoreline (C/LKS). The sites were classified as protected from poachers (P), under light hunting pressure (LHP), and under heavy hunting pressure (HHP). Clean protected (P) lagoons had three times as many capybaras as LHP ones (30.7 and 10.9 C/LKS, respectively), and thirty times those under HHP (1.0 C/LKS). Protected marshes and dirty lagoons had even higher capybara densities (52.5 and 50.0 C/LKS, respectively). Gallery forests under LHP had low densities (6.3 C/LKS), and protected cutwaters intermediate densities (27.5 C/LKS). Erosion ditches had exceptionally high densities (900 C/LKS), probably because cattle were fenced out, reducing forage competition. These densities, when converted to the standard unit area measurement (individuals/ha), were similar to those obtained by other researchers in the Brazilian Pantanal, and somewhat smaller than those in the Venezuelan Llanos. Mean number of capybaras per group remained relatively constant in all habitats (averages ranged between 9.2 and 11.8 individuals/group) but its coefficient of variation was much higher in LHP sites, probably because social structure was altered severely by hunting. The overall ratio of young to adults and juveniles was 1:7.4. In one of the sites, 13 of 34 groups (38.2%) were with young (average of 17 capybaras per group, 4.7 of which were young), confirming that this species can reproduce all year long.Requests for reprints should be sent to: Dr. J. Rabinovich.     

Rumen ophryoscolecid protozoa in the hindgut of the capybara (Hydrochoerus hydrochaeris)

Rumen ophryoscolecid protozoa were observed in feces obtained from two capybara (Hydrochoerus hydrochaeris) housed at the Columbus Zoo, Columbus, Ohio. Total numbers were 58.1 X 10(4) and 19.0 X 10(4) per gram of wet feces in a male and female capybara, respectively. Four common rumen species of Entodinium were observed in the feces from both animals, with low numbers of Eudiplodinium maggii and Elytroplastron bubali also occurring in the male. Establishment of rumen ophryoscolecid ciliates in the intestinal tract of non-ruminant herbivores has not been reported previously.     

The capybara (Hydrochoerus hydrochaeris) as a reservoir host for Trypanosoma evansi

Discovery of two ill horses and three dogs naturally infected with Trypanosoma evansi near an experimental station in the Eastern Plains of Colombia led to a search for reservoir hosts of the parasite. Infection was detected in 8/33 healthy capybaras (Hydrochoerus hydrochaeris), none of the remaining 14 horses, and none of 32 Zebu cattle (Bos indicus), 18 paca (Cuniculus paca) and 20 spiny rats (Proechimys sp.). Contrary to common opinion, the results indicated a carrier state in the capybara. Diagnosis was based on morphology, behaviour in albino rats, and pathogenicity and host range in domestic animals.     

The Vocal Repertoire of Golden-Faced Sakis,Pithecia chrysocephala,and the Relationship Between Context and Call Structure

International Journal of Primatology - Vocalizations are a vital form of communication. Call structure and use may change depending on emotional arousal, behavioral context, sex, or social...     

Purification and characterization of transducin from capybara Hydrochoerus hydrochaeris

Polypeptides of approximately 39, 36 and 相似文献