Conflict between Fishermen and Giant Otters Pteronura brasiliensis in Western Brazilian Amazon

The recovery of giant otter populations after the hunting prohibition and restriction of the pelt trade resulted in more frequent conflicts with fishermen. In this study, fisherman–giant otter conflicts were analyzed in the Uacari Sustainable Development Reserve, where giant otters are accused of interfering with fisheries by eating the fish (predation), frightening the fish away (local interference), and damaging fishing equipment (direct interference). Interference by predation was analyzed by evaluating overlap in fish species consumption between humans (measured by subsistence and commercial catches) and giant otters. The giant otter diet was assessed from fecal samples, and the human diet through questionnaires. Local and direct interferences were analyzed through fish samples using gillnets and comparing capture efficiency with and without giant otters’ presence. The overlap between human and giant otter diets was low (0.37), varied seasonally, and was smaller in the low water (0.24) than in the high water period (0.60), when both species tend to be more generalists. Overlap between fish species consumed by giant otters and those exploited by commercial fisheries was small (0.34). Giant otter presence during the experimental fishing was low (9.5%), restricted to the high water period, and did not significantly reduce the captures (U = 13, P = 0.61). The low overlap in diet may be a result of differences in preferences and fishing strategies. The conflict between giant otters and fishermen is greater in the high water period, when the income of the fisheries decreases; however, the conflict seems to be mainly motivated by the resident's prejudice against giant otters.     

Biology and conservation of the Giant Otter Pteronura brasiliensis

The Giant Otter Pteronura brasiliensis (Zimmermann, 1780) is endemic to South America, distributed throughout the Orinoco, Amazon and La Plata River basins and numerous localities in the Guyanas. This otter is the largest member of the family Mustelidae, clearly distinguished from other South American otter species by morphological and behavioural characteristics. Large-scale pelt hunting in the 1950s and 1960s led to the classification of the species as 'vulnerable' by the World Conservation Union (IUCN, 1990). Habitat degradation and destruction now present the largest threat to remaining populations. The current distribution of the Giant Otter is presented, emphasizing recent information collected in the Amazon Basin. Morphology, systematics, habitat, behaviour, diet, predation, competition, reproduction, development and physiology are discussed. New data on habitat use and preference, behaviour and diet in northern Amazônia are included, and recommendations for future conservation measures are made. Because of the decimation of the Giant Otter in its southern distribution and the habitat destruction occurring in the remainder of its range, we recommend that this species be elevated to 'endangered' status in the IUCN Red Data Book.     

Aid to a Declining Matriarch in the Giant Otter (Pteronura brasiliensis)

Scientists are increasingly revealing the commonalities between the intellectual, emotional and moral capacities of animals and humans. Providing assistance to elderly and ailing family members is a human trait rarely documented for wild animals, other than anecdotal accounts. Here I report observations of multiple forms of assistance to the declining matriarch of a habituated group of giant otters (Pteronura brasiliensis) in Manu National Park, Peru. The otter group had been observed annually for several years and all members were known individually. In 2007, the breeding female of the group failed to reproduce and appeared to be in physical decline. She begged from other family members 43 times over 41 contact hours and received food 11 times. Comparisons with 2004–2006 demonstrate that the family''s behavior in 2007 constitutes a role-reversal, in which the majority of assistance and prey transfers accrued from young-to-old rather than from old-to-young. As in human societies, both non-adaptive and adaptive hypotheses could explain the family members'' aid to their declining matriarch. I suggest that giant otter families may benefit from the knowledge and experience of an elderly matriarch and “grandparent helper,” consistent with the “Grandmother Hypothesis” of adaptive menopause in women.     

Feeding Ecology of the Giant Otter,Pteronura brasiliensis1

The food habits of the giant otter, Pteronura brasiliensis, were determined by analyzing fecal samples collected year–round from communal latrines at Xixtiaú Creek (00°48'S, 61°33'W), Jauaperi River (central Brazilian Amazon) between 1993 and 1994. Communal latrines were also sampled during the low water season at Aquidauana River (19°32'S, 56°40'W), Pantanal of Mato Grosso do Sul (central Brazil). Fragments of vertebrae, mandibles, teeth, scales, and fin spines provided an estimate of the diet composition. Remains of fish were present in all of the samples. The main fish groups found at Xixuaú Creek were Perciformes, represented specifically by Cichlidae (97.3% of all samples), Characiformes (86.5%) and Siluriformes (5.4%). The Characiformes were represented mainly by E, rythrinidae (Hoplias sp. 90.6%), followed by Serrasalmidae (28%). The Anostomidae occurred with a frequency of 18.7 percent, while Characinae, Bryconinae, and Cynodontidae were only observed in 3.1 percent of the Characiformes records. At Aquidauana River, the Characiformes were the most frequent fish group, represented in 100 percent of all samples, followed by Siluriformes (66.6%) and Perciformes (33.3%). The fish from the main groups identified in the diet of the giant otters prefer riverbanks, lakes, and flooded forests. The feeding habits of Pteronura brasiliensis are probably influenced by the vulnerability and abundance of the prey consumed by this carnivore.     

Demography of the Giant Otter (Pteronura brasiliensis) in Manu National Park,South-Eastern Peru: Implications for Conservation

The giant otter (Pteronura brasiliensis) is an endangered semi-aquatic carnivore of South America. We present findings on the demography of a population inhabiting the floodplain of Manu National Park, south-eastern Peru, arising from 14 annual dry season censuses over a 16 year period. The breeding system of territorial groups, including only a single breeding female with non-reproductive adult ‘helpers’, resulted in a low intrinsic rate of increase (0.03) and a slow recovery from decades of hunting for the pelt trade. This is explained by a combination of factors: (1) physiological traits such as late age at first reproduction and long generation time, (2) a high degree of reproductive skew, (3) small litters produced only once a year, and (4) a 50% mortality between den emergence and age of dispersal, as well as high mortality amongst dispersers (especially males). Female and male giant otters show similar traits with respect to average reproductive life-spans (female 5.4 yrs., male 5.2 yrs.) and average cub productivity (female 6.9, male 6.7 cubs per lifetime); the longest reproductive life spans were 11 and 13 years respectively. Individual reproductive success varied substantially and depended mainly on the duration of dominance tenure in the territory. When breeding females died, the reproductive position in the group was usually occupied by sisters or daughters (n = 11), with immigrant male partners. Male philopatry was not observed. The vulnerability of the Manu giant otter population to anthropogenic disturbance emphasises the importance of effective protection of core lake habitats in particular. Riverine forests are the most endangered ecosystem in the Department of Madre de Dios due to the concentration of gold mining, logging and agricultural activities in floodplains, highlighting the need for a giant otter habitat conservation corridor along the Madre de Dios River.     

Cross-species characterisation of polymorphic microsatellite loci in the giant otter (Pteronura brasiliensis)

Nineteen microsatellite loci developed for the Eurasian otter (Lutra lutra) and 15 loci developed for the North American river otter (Lontra canadensis) were tested for ease of amplification and degree of polymorphism on a set of 20 giant otter (Pteronura brasiliensis) faecal samples from the Bolivian Amazon basin. Nineteen loci amplified consistently well, with polymorphisms ranging from two to nine alleles and observed heterozygosity ranging from 0.15 to 0.85.     

Carnivora: the primary structure of the giant otter (Pteronura brasiliensis, Mustelidae) hemoglobin

The hemoglobin of the Giant Otter (Pteronura brasiliensis, Carnivora) contains only one component. The complete primary structures of the alpha- and beta-chains are presented. The globin chains were separated by high-performance liquid chromatography and the sequences determined by automatic liquid- and gas-phase Edman degradation of the chains and their tryptic peptides. The alpha-chains show 18 and the beta-chains 12 exchanges compared with human alpha- and beta-chains, respectively. In the alpha-chains, two substitutions involve alpha 1/beta 1-contacts and one a heme-contact. In the beta-chains one alpha 1/beta 1-, one alpha 1/beta 2- and one heme-contact are exchanged. The alpha- and beta-chains of the Giant Otter are compared to those of the Common Otter and other Carnivora hemoglobins.     

Vocal Repertoire of Captive Capybara (Hydrochoerus hydrochaeris): Structure,Context and Function

In this work we describe the structure, behavioral context and functionality of the vocal repertoire of capybaras, a social Caviomorph rodent. Additionally, since territoriality is present in this species, we hypothesize the occurrence of vocal differences among social groups. We analyzed a total of 2069 calls emitted by 28 animals from three different social groups. The capybara’s repertoire is comprised by seven call types (whistle, cry, whine, squeal, bark, click and tooth‐chattering). The vocalizations were functionally categorized as contact, alarm, distress and agonistic calls considering their behavioral contexts. The click calls emitted by the adults of the three captive capybara groups were significantly different, confirming our hypothesis of social groups’ vocal differences. The richness of interactions mediated by vocalization in capybaras suggests that the species’ communication is an important mechanism to regulate social encounters and to alert members of the group about environmental cues.     

Genetic diversity and population structure in the endangered giant otter, Pteronura brasiliensis

We assessed levels of genetic diversity and investigated patterns of population structure in three remnant populations of the endangered giant otter, Pteronura brasiliensis, using microsatellite loci. All populations displayed moderate to low levels of heterozygosity and allelic richness (H _O 0.56–0.57, A _R 4.00–5.15) and effective population sizes were low (N _E 10.8–54) although only the Iténez population exhibited the signature of a genetic bottleneck. Population structure analyses revealed a pattern in which the populations of the Upper Amazon, Orinoco and Essequibo drainages comprised partially differentiated segments of a northern South American metapopulation, whereas the population of the Iténez appeared isolated. The observed patterns are congruent with previous mitochondrial DNA analysis which suggested the Iténez and northern South American groups constitute two evolutionary significant units. The results presented here should be considered in planning future policies aiming to manage the recovery of the giant otter across its range.     

Evolutionary history and identification of conservation units in the giant otter, Pteronura brasiliensis

The giant otter, Pteronura brasiliensis, occupies a range including the major drainage basins of South America, yet the degree of structure that exists within and among populations inhabiting these drainages is unknown. We sequenced portions of the mitochondrial DNA (mtDNA) cytochrome b (612bp) and control region (383 bp) genes in order to determine patterns of genetic variation within the species. We found high levels of mtDNA haplotype diversity (h = 0.93 overall) and support for subdivision into four distinct groups of populations, representing important centers of genetic diversity and useful units for prioritizing conservation within the giant otter. We tested these results against the predictions of three hypotheses of Amazonian diversification (Pleistocene Refugia, Paleogeography, and Hydrogeology). While the phylogeographic pattern conformed to the predictions of the Refugia Hypothesis, molecular dating using a relaxed clock revealed the phylogroups diverged from one another between 1.69 and 0.84 Ma, ruling out the influence of Late Pleistocene glacial refugia. However, the role of Plio-Pleistocene climate change could not be rejected. While the molecular dating also makes the influence of geological arches according to the Paleogeography Hypothesis extremely unlikely, the recent Pliocene formation of the Fitzcarrald Arch and its effect of subsequently altering drainage pattern could not be rejected. The data presented here support the interactions of both climatic and hydrological changes resulting from geological activity in the Plio-Pleistocene, in shaping the phylogeographic structure of the giant otter.     

Behavioral Repertoire, Age Polyethism and Adult Transport in Ectatomma opaciventre (Formicidae: Ponerinae)

This study describes the behavioral repertoire of a mature colony of Ectatomma opaciventre Roger. Twenty-eight different behavioral acts were recorded from 4538 individual observations. There was evidence of age polyethism, with young workers performing significantly more brood care and allogrooming than older workers. Experiments were also performed to investigate the behavioral organization of nest relocation in E. opaciventre. This complex social behavior was regulated by a few workers which specialized in transporting nestmates, including other workers, winged gynes, males, and the queen. Winged gynes were also observed performing adult transport. The carrying posture utilized in E. opaciventre is similar to that in other ponerines, although some idiosyncratic features were detected.     

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.     

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.     

The Vocal Repertoire of Barbary Macaques: A Quantitative Analysis of a Graded Signal System

The vocal behavior of Barbary macaques (Macaca sylvanus) was studied in an outdoor enclosure at Rocamadour, France. Ad libitum recordings were made across a broad array of socioecological contexts from 92 individually identified subjects from all age—sex classes. From the recordings, 8479 calls were sampled and submitted to a Fourier transform. A custom software program was used to determine 35 acoustic parameters describing the call in terms of its frequency and time dynamics. On these parameters a cluster analysis was used to examine the acoustic morphology of the Barbary macaque vocal repertoire. The analysis revealed a highly graded structure with intergraded variations between different clusters (‘call types’). There were clear age-related preferences in usage of different clusters, but animals of all ages were potentially able to produce the whole array of call types. The major sex difference was a differential use of certain call types in specific situations. Despite a clear sex dimorphism in body size no significant sex differences in the acoustic structure of calls in adults was found. There were no unidirectional relationships between the acoustic structure of a call and the context in which it was uttered, although call usage was more specific in some contexts than in others. The results suggest that the major factor underlying the variation in acoustic structure reflect the internal state of the caller.