Giant Otter Pteronura Brasiliensis Research Articles

Status and distribution of Paraguayan Mustelidae

Five species of Mustelidae are known to occur in Paraguay – Tayra Eira barbara, Lesser Grison Galictis cuja, Greater Grison Galictis vittata, Giant Otter Pteronura brasiliensis and Neotropical Otter Lontra longicaudis. However, Paraguayan data regarding the distribution and status of these species in Paraguay is not easily obtainable, and scattered amongst numerous, often obscure publications. Paraguayan literature and specimens were reviewed to compile data on the distribution and status of these species in the country and records are presented in a hierarchical manner reflecting the reliability of each report. Data on these species in Paraguay are sorely lacking and our knowledge of distribution in the country is poor. The specimen record is incomplete and severely biased towards the Chaco region. Most species are apparently widespread and fairly common in the country. Giant Otter has a more restricted distribution, mainly in the Pantanal region. The precise distribution of the Greater Grison is unclear, probably because of widespread confusion of this species with the Lesser Grison.

Giant otter Pteronura brasiliensis density and abundance in Llanos Orientales de Colombia in the Orinoco basin

AbstractThe giant otter Pteronura brasiliensis, categorized as Endangered on the IUCN Red List, was once widely distributed throughout South America. By the middle of the 20th century the giant otter had become locally extinct along the main rivers of the Orinoco basin. Although some populations seem to have recovered, the paucity of information available does not permit a full evaluation of the species' conservation status. The objective of this study was to estimate the abundance and density of the giant otter population along the Orinoco river in the municipality of Puerto Carreño, Vichada, Colombia, where there is important commercial and recreational fishing. Thirty-nine linear km were surveyed, repeatedly, with a total of 315 km of surveys. Population size was estimated by direct counts of individuals. All individuals detected were photographed and identified individually from their throat pelage patterns. In total, 30 otters were identified, giving a minimum density of 0.77 individuals per km, one of the highest reported for the species in Colombia. Given the high density in this well-developed area, our results highlight the importance of this population for the conservation of the species.

First report on the colpocytology and serum steroid hormone levels of Giant otters Pteronura brasiliensis

Considering the importance of tools for the reproductive monitoring and management of Giant otters Pteronura brasiliensis in the wild or in captivity, this study reports the relationship among the colpocytology, reproductive serum hormone (progesterone and oestradiol) levels and ovarian morphology of adult Giant otters. Blood and vaginal cytology samples were obtained from four adult females (two free‐ranging and two in human care). The ovaries were collected from the captive females. The data were correlated to define the phase of the oestrous cycle of each animal. The results suggest the feasibility of using hormone analysis or colpocytology to aid in the reproductive monitoring of Giant otters in human care. In addition, these tools could be used to define the reproductive status of individual wild Giant otters during capture procedures.

Giant otter Pteronura brasiliensis breeding programmes: challenges and current developments

There is a history of over 130 years of Giant otters Pteronura brasiliensis in zoos. Thanks to the intensive work carried out at numerous holding institutions and huge progress in husbandry practices, especially over the past 20 years, significant success has been achieved in the breeding of this Endangered species. Initially kept for awareness and education purposes, the breeding programme for the Giant otter is gradually evolving into a global management programme capable of combining ex situ and in situ conservation. At the time of writing, zoos on four continents (South America, North America, Europe and Asia) work together with partners from research, conservation and the authorities to preserve this wonderful species, for which a reintroduction project is in the process of being established.

Cryptosporidium spp. and Giardia sp. in aquatic mammals in northern and northeastern Brazil.

Cryptosporidium and Giardia are protozoans that can infect humans and wild and domestic animals. Due to the growing importance of diseases caused by protozoan parasites in aquatic species, we aimed to evaluate the frequency of infection by Cryptosporidium spp. and Giardia sp. in aquatic and marine mammals in the northern and northeastern regions of Brazil. We collected 553 fecal samples from 15 species of wild-ranging and captive aquatic mammals in northern and northeastern Brazil. All samples were analyzed by the Kinyoun technique for identification of Cryptosporidium spp. oocysts. Giardia sp. cysts were identified by means of the centrifugal-flotation technique in zinc sulfate solution. Subsequently, all samples were submitted for direct immunofluorescence testing. The overall frequency of infection was 15.55% (86/553) for Cryptosporidium spp. and 9.04% (50/553) for Giardia sp. The presence of Cryptosporidium spp. was detected in samples from 5 species: neotropical river otter Lontra longicaudis (15.28%), giant otter Pteronura brasiliensis (41.66%), Guiana dolphin Sotalia guianensis (9.67%), Amazonian manatee Trichechus inunguis (16.03%), and Antillean manatee T. manatus (13.79%). Giardia sp. was identified in L. longicaudis (9.23%), P. brasiliensis (29.16%), pygmy sperm whale Kogia breviceps (100%), dwarf sperm whale K. sima (25%), S. guianensis (9.67%), T. inunguis (3.81%), and T. manatus (10.34%). This is the first report of Cryptosporidium spp. in L. longicaudis, P. brasiliensis, and S. guianensis, while the occurrence of Giardia sp., in addition to the 2 otter species, was also identified in manatees, thus extending the number of hosts susceptible to these parasitic agents.

Estudio etnozoológico kichwa de la nutria gigante Pteronura brasiliensis (Zimmerman, 1780) en la baja Amazonía central del Ecuador

The giant otter Pteronura brasiliensis is the largest mustelid of Neotropical riparian and lacustrine environments. It is endangered throughout the Amazon basin, and in Ecuador is critically endangered because of intensive hunting in past decades, especially in the northeast of the country. Very little is known about their status in the central Amazon region of Ecuador, but it is presumed the existence of more stable populations than those of the northeast remnant populations. The territory of the Pastaza province covers a major portion of the central Amazon and is still well preserved because it is the birthplace of various indigenous peoples for whom the giant otter is a protective spirit. Currently, the contribution of knowledge of local communities is being recognized as an important element for the monitoring and conservation of wildlife. In this context, this study proposes to document the ethnozoological Kichwa knowledge about the distribution, biology and uses of the giant otter in the border area of Pastaza. Interviews were conducted with 12 fishermen from the Ancestral People of the Kawsak Sacha territory. Fishermen provided information on new sites in Pastaza where there are still populations of giant otters. This article also provides unpublished data on prey, predators, size and composition of groups sighted, indirect traces, times of increased sightings, daily schedule of activity, breeding season, uses and spiritual value of the giant otter from the Kichwa ethno-knowledge. This allows us to suggest the need for further research in ethnozoology among local communities, as an strategy to promote the conservation of threatened wildlife species in the Amazon, from a more inclusive and equitable perspective.

How to sex Giant otterPteronura brasiliensis(Gmelin, 1788) cubs

Sexing living neonate mammals may be difficult as external genitalia may be poorly developed and time may be limited for a detailed examination. Four neonate cubs of the Giant otter Pteronura brasiliensis were examined in order to determine a method to distinguish between the sexes. The distance between anal and genital openings in ♂ cubs is about eight times greater than that in ♀ cubs, providing a simple method for determining sex.

Recovery of the Endangered giant otter Pteronura brasiliensis on the Yavarí-Mirín and Yavarí Rivers: a success story for CITES

The giant otter Pteronura brasiliensis was hunted almost to extinction in the Peruvian Amazon during a period of professional trade in wild animal skins during 1920-1973. In 1973 the Department of Agriculture of Peru (INRENA) prohibited commercial hunting in the Peruvian Amazon, and the giant otter was included in Appendix I of CITES. From 1973 to 2004 giant otter populations expe- rienced a slow recovery in numerous rivers of the Peruvian Amazon. Here, we report the population growth of the giant otter on the Yavari ´-Mirin and YavariRivers in north- east Peru. The first evaluations of giant otter populations in these rivers, in which no individuals were sighted, were in 1992-1993. During surveys in 1996 and 1997 two individ- uals were sighted. In 2001, 19 individuals were sighted and in 2003 and 2004, 41 individuals were observed. This in- crease demonstrates a slow recovery and shows that the population has not yet reached its carrying capacity. The prohibition of international trade in otter skins by CITES, supported by INRENA, helped the population recover and was important in the conservation of this species.

Infrared thermography of the body surface in the Eurasian otter Lutra lutra and the giant otter Pteronura brasiliensis

The body surface temperatures of the Eurasian otter Lutra lutra and the tropical giant otter Pteronura brasiliensis were studied based on detailed infrared thermography. The Eurasian otter mainly used its feet to dissipate excess heat, whereas the giant otter lost more heat from the whole body and tail. In both species, the temperature at the surface of the feet tended to decrease to a temperature similar to that of the water when the animal was submerged. The same was observed for the tail of the giant otter, and of the Eurasian otter during winter. In the Eurasian otter, tempera- tures of the air layer trapped within the fur were >10°C above the temperature of the ambient air or water. A specific heating of sensory organs on the head could be observed.

Age estimation in giant otters (Pteronura brasiliensis) (Carnivora: Mustelidae) using growth layer groups in canine teeth

The canines of six giant otters Pteronura brasiliensis (5 males and 1 female) from the zoological collection of the National Institute of Amazonian Research (INPA) were analyzed for age estimation. Of these, two were from known-age individuals of 2 and 5 years. Ages were read counting the Growth Layer Groups (GLGs) observed in thin sections (30μm) of decalcified teeth. GLGs were present in the dentine but were not conspicuous; age estimates were only reliable when counted in the cementum. Periodicity of GLGs and age estimates were calibrated with the known-age individuals. Results revealed an annual deposition pattern of GLGs in the cementum of giant otter canines, and no apparent differences were found in the GLG patterns observed between males and females, or between captive and free-ranging individuals. The youngest and oldest giant otters analyzed were 2 and 20 years old, respectively. These results suggest that the longevity of captive giant otters is around 20 years. The age determination technique applied here proved to be useful for age estimation in giant otters and can contribute as a powerful tool for future studies on the population dynamics of P. brasiliensis , which is currently classified as endangered.

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.