Under field conditions, body size is not a reliable indicator of gender or age; some males were noticeably smaller than their partners and older animals were not always the largest [16]. Although some breeding occurs throughout the year, the peak of the breeding season is from late spring to early summer. Wildlife Conservation Research Unit, University of Oxford, Abingdon, Oxfordshire, United Kingdom, Year-round, peak in late spring-early summer, 2. Reproductive maturity is reached when they are 2 years old. Unfortunately, due to habitat destruction from logging, farming, and mining, the Giant Otter is near extinction, with a wild population … The Manu population was sub-divided into known-age (i.e. https://doi.org/10.1371/journal.pone.0106202.s001. Frankfurt Zoological Society, Frankfurt, Germany, Affiliation Their long tail may add as much as 70cm (28in) to this body length. Yes If giant otters seen in an earlier census were not observed in subsequent surveys, they were considered dead. Most otter groups reacted to the survey canoe by approaching and repeatedly craning head and neck straight out of the water, a behaviour known as ‘periscoping’. An average giant otter will weigh between 22 and 32kg (49-71lbs). We therefore followed a similar approach to that adopted by Creel and Creel [13] for wild dogs. Manu National Park (16,921 km2) lies in the Department of Madre de Dios, south-eastern Peru, at the foothills of the tropical Andes. Common name: Giant otter, giant Brazilian otter, giant river otter. https://doi.org/10.1371/journal.pone.0106202.t002. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. Yes PLoS ONE 9(8): Individual reproductive success varied substantially and depended mainly on the duration of dominance tenure in the territory. Transient group size ranged from 2 to 5, with a mean of 2.9 (n = 16, se = 0.22). Persecution, degradation of the jaguar's habitat, and decrease in its prey are thought to have reduced the species population to less than 50,000 mature breeding individuals in the wild. Males can then be distinguished from females by the larger space between the sources of the urine and scat streams [45]. Nature Services Peru, Department of Cusco, Cusco, Perú, PJ received support from the Whitley Wildlife Conservation Trust (http://www.wwct.org.uk/) and the John Ellerman Foundation (http://ellerman.org.uk/). The Giant River Otter only lives in three river systems: the Am… The giant otter can grow to more than 6 feet (2 meters) long and 70 pounds (32 kg), nearly twice as large as its American counterparts. They will seek a peaceful place (or "picnic spot") to eat their prey. Giant Otters are social creatures who learn from each other and live in tight-knit extended families. Breeding males produced a mean of 6.7 cubs per lifetime (SE 1.08). Known throughout much of their range as 'river wolf', they are amongst South America's top carnivores. Social activities include hunting, grooming, resting and communicating. Only 11.3% were born during the wet season (first and fourth quarters combined). Animals that were seen in 1996 and again in 1999 were inferred for the intermediate years. Cubs of the original pair were invariably adopted by the immigrant males and groups remained stable throughout the transitions, usually producing new litters the following year. Life expectancy peaks between 4.5 and 5.5 years, with the longest-lived male and female last seen at 15.5 years and at least 13.5 years old respectively. Overall, currently Giant otters are classified as Endangered (EN) and theirs numbers today are decreasing. It appears, retrospectively, that the population in the floodplain of Manu National Park was still in a process of recovery from the impact of the pelt trade - not all the available territories were occupied when this study was initiated in 1991. https://doi.org/10.1371/journal.pone.0106202.g001. Its thick, velvety brown fur has characteristic white markings around the neck. The giant otter (Pteronura brasiliensis, Zimmermann 1780) is a semi-aquatic carnivore of South America, occurring east of the Andes in the Orinoco, Amazonas, and Parana basins, and in the Guianas [4], [5]. The social system of giant otters is therefore unusual [15]; a typical giant otter population consists of highly cohesive multi-male/female families with defended territories, plus transients that have left their natal groups on attaining sexual maturity [4], [16], [17]. The Giant otter was discovered by Gmelin in 1788. In Manu National Park, Schenck [33] and Staib [16] found that home ranges of giant otters typically include one or more oxbow lakes, the associated stretch of river, and adjacent swamp areas and streams (which are inaccessible for observers and therefore make it impossible to define the exact extent of home ranges). Each census covered 230 river kilometres and a core group of 20 oxbow lakes (ranging in total surface area from 10.5 to 101.9 hectares, with an average of 36.6 hectares), together with 11 additional lakes which were surveyed less intensively; the census area (number of oxbow lakes and river kilometres) was constant between the three consecutive census teams. At Lake Salvador, where tourism is most intense, we did not observe any offspring this year either - which is an exception among Manu´s otter population. The giant otter (Pteronura brasiliensis) is an endangered semi-aquatic carnivore of South America. The variance in reproductive success thus tended to be higher in males compared to females. Furthermore, in the period 2002–2011, the average annual growth of the economy in Madre de Dios was 7.3%, higher than the national average growth of 6.4% [39]. Entire litters could have been missed from the census if all their members died earlier. The current total population is estimated to be somewhere between 1000-5000 individuals. Discover a faster, simpler path to publishing in a high-quality journal. Post-independence survivorship differed between the sexes (SAS PROC LIFESTEST log-rank χ2 = 5.9, P = 0.015) (Figure 7); this is associated with a marked pulse in male dispersal at age 3.0, resulting in lower male survivorship at this time. San Diego Zoo Global Peru, Department of Cusco, Cusco, Perú, https://doi.org/10.1371/journal.pone.0106202.g004. For more information about PLOS Subject Areas, click Frankfurt Zoological Society, Frankfurt, Germany. Giant Otter This South American otter is the world's largest, at some 6 feet long. Immigrants were only recruited into a resident group if they claimed the dominant breeding status. https://doi.org/10.1371/journal.pone.0106202.g002, https://doi.org/10.1371/journal.pone.0106202.g003, https://doi.org/10.1371/journal.pone.0106202.t001. spend significantly less time obtaining food than do smaller groups (5 inds. Illegal killing still occurs, often at the hands of fishermen, who see Giant otters as competition for fish. No, Is the Subject Area "Peru" applicable to this article? Despite a recent recovery in some areas following banning of the fur trade, the species now faces several emerging threats that remain poorly understood. Yes Group and territory defence is cooperative [7], [21], though intra-specific agonistic encounters are rarely observed [4], [16], [21] with scent marking at latrines thought to be important for territorial demarcation [4], [16], [18]. Although widely distributed on a continental scale, overall they may occupy less than 5%, often less than 1% of a given watershed. Although its range is large, the giant otter’s population is sparsely distributed and the species is today only found in a fifth of … Jessica Groenendijk, Frank Hajek, Christof Schenck, Elke Staib, and Jorge Calvimontes would like to thank Peru’s National Service for Protected Areas (SERNANP) for the opportunity to work in Manu National Park. In order to determine gender differences in demographic variables, otters were sexed. It is not clear whether these changes of one member of the breeding pair involved active displacement by the newcomer or whether the newcomer simply occupied an already vacant position (i.e. Each year, therefore, several dominant females failed to raise a litter to 0.5 years. The observed mean number of cubs born per resident group year (i.e. The total population of giant river otters in the wild could now be as low as 5,000. (2014) Demography of the Giant Otter (Pteronura brasiliensis) in Manu National Park, South-Eastern Peru: Implications for Conservation. There are 1-5 pups in a litter (usually 2-3) and they stay in the family den until they are 2-3 weeks old. A family comes out of their home for an afternoon activity. As a norm, the dominant female of a giant otter group produced one litter per year. White-water lakes are nutrient rich and highly productive; they have considerably higher fish biomass per unit area than their associated river channels - one study reports a fish biomass density of 13.4 g m−2 in these lakes compared with 3.4 in their associated water channels [34]. Only by facilitating the return of giant otters in the Madre de Dios floodplain will the population of the entire watershed reach Ne ≥500 individuals, our minimum conservation goal for a genetically viable population [43]. Successors were trained in census methodology in the field by the preceding census team, and the same field equipment was used. Observations of captive individuals suggest that giant otters of both sexes reach sexual maturity at between 2 and 3 years of age [20], [22]. There are estimates for the populations of a few areas: 2,000-5,000 individuals in the Brazilian Pantanal; 180-400 individuals in Madre de Dios, southeastern Peru; 31 individuals in Cantao State Park, Brazil; 75 individuals in Amana, Brazil; at least 130 individuals in Balbina Lake, Brazil; 54 individuals in Araguaia, above Bananal Island; 32 individuals in Yasuni National Park, Ecuador; and at least 35 individuals in Rewa Head, Guyana. Hunting in the mid-1970s pushed giant otter populations to the brink of extinction. These otters are able to swim 330 feet (100 meters) in less than 30 seconds. No, Is the Subject Area "Conservation science" applicable to this article? However, there are several emerging threats to this sensitive species. If intruders invade the family's territory, the parents will defend it and their family members. In 1973, the commercial hunting of wildlife was banned in Peru and other countries of the giant otter’s range, and the species was listed under Appendix 1 of CITES (Convention of International Trade in Endangered Species) in 1975 [10], effectively leading to the collapse of the international pelt market. Competing interests: The authors have read the journal’s policy and the authors of this manuscript have the following competing interests: JG, FH, CS, ES, and JC were employed by the Frankfurt Zoological Society at the time the field research was conducted. The giant otter is the South American cousin to the sea and river otters of North America, as well as those of Europe and Africa. 6 months old [17], [20] and rely to a great extent on other group members for prey provision until 1.5 years old [16]. 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. We used both male and female offspring because many cubs could not be sexed. In some of its range countries the populations are fairly stable but giant otters have gone extinct in some of their range countries. Since paternity is thought to be known and only the dominant pair in the group breeds, we divided cub production equally between the sexes and calculated ‘mx’ as half the total number of offspring for each parent. This means that changes in this specific habitat, or impacts there-in, will have severe effects even if only a fraction of the overall area is affected. We estimated the ages of 30 transient and reproductive immigrants to the Manu system using our known-age population and distributed these individuals amongst the cohort and fecundity age classes as accurately as possible according to their sex (male, female, unknown); this has the consequence of extending the life-spans of some dispersers and breeding animals, rather than assuming they all died on disappearance. https://doi.org/10.1371/journal.pone.0106202.s002, https://doi.org/10.1371/journal.pone.0106202.s003. Habitat fragmentation and loss, as well as pollution are the current major threats to the Giant otter, as the areas where they live are degraded and destroyed by logging, mining and damming. following the predecessor’s death). However, sexing was more difficult in adult females that had not lactated, or in cubs, juveniles and sub adults of both sexes. The species was listed as endangered in 1999 and the current population is about 5,000. Giant otter population sizes were estimated to illustrate population trends for two different contexts of observed den density representing the pre- and post-filling phases of the reservoir. Delayed implantation, suggested by Sykes-Gatz [20] for giant otters in captivity, was confirmed by Corredor and Muñoz [29] at Cali Zoo. Of 41 reproductively mature females, 11 (27%) were not recorded to produce a single litter, 17 (41%) produced only one or two litters, and 13 (32%) produced three litters or more. As no single protected area in the Madre de Dios region is close to harbouring a demographically viable population (Ne ≥50), interchange of individual otters between the sub-populations is necessary if we are to lower the probability of immediate risk of local extinction in the face of future threats. 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