When they visit latrines, otters often defecate and urinate simultaneously [4] (fecaluria). Reproductive animals usually remained in their home range until death or disappearance (in 38 of 40 cases). 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. Is the Subject Area "Otters" applicable to this article? first recorded as cubs in the study area) and estimated-age otters (first recorded as transients or as group members). Inferred animals or groups are those which are assumed to have been in the population and study area in a given year when they were identified in both the previous and subsequent census, and were included in the analyses; in the case of groups for which there was a gap in data continuity, the number of individuals was estimated to be the average of group sizes in the years before and after that gap (provided key group members could be identified). 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]. Effective Protected Area design and broader wetland landscape management initiatives are therefore critical for the long term conservation of the species in Madre de Dios. If intruders invade the family's territory, the parents will defend it and their family members. The giant otter, an endangered apex predator in Amazon river ecosystems, was nearly driven to extinction because of demand for its fur. Female and male giant otters show similar traits with respect to average reproductive life-spans (female 5.4 yrs., male 5.2 yrs.) It lives only in the rivers and creeks of the Amazon, Orinoco, and La Plata river systems. In some of its range countries the populations are fairly stable but giant otters have gone extinct in some of their range countries. No, Is the Subject Area "Rivers" applicable to this article? Gestation lasts 65-70 days and the altricial young are born in late August until early October. The mean annual observability of resident groups was 85% (range 71–100%), while that of transients was 59% (range 0–100%). In 11 instances the breeding male disappeared and was replaced by an immigrant adult male. Its thick, velvety brown fur has characteristic white markings around the neck. As of now, 5000 giant otters are left in the world. The population of giant otters were decimated and only 12 where left by 1971. Driven by increasing gold prices and new road access, the extent of gold mining in the Madre de Dios region increased from less than 10,000 hectares in 1999 to more than 50,000 hectares in 2012. 0.5 yrs old, well after emergence from the den, which occurs at about 2 months. (2014) Demography of the Giant Otter (Pteronura brasiliensis) in Manu National Park, South-Eastern Peru: Implications for Conservation. The rate of expansion jumped from 2,166 ha per year before 2008 to 6,145 ha per year thereafter. Frankfurt Zoological Society, Frankfurt, Germany, Affiliation We therefore followed a similar approach to that adopted by Creel and Creel [13] for wild dogs. Currently, there are almost none in Argentina and Uruguay, and they are very rare in Paraguay. Observed litter size at time of census ranged from 1 to 5 with a mode of 2 (post-emergence mean = 2.2, SE = 0.04, n = 78). An average giant otter will weigh between 22 and 32kg (49-71lbs). In total, 172 cubs were observed in 78 litters between 1991 and 2006. Wildlife Conservation Research Unit, University of Oxford, Abingdon, Oxfordshire, United Kingdom, Affiliations For a large top-chain predator that does not live at high population densities, this was an unsupportable harvest rate. The breeding male could be identified by its behaviour, specifically that of intensive marking, and by its year-on-year permanence in the group (non-breeding males do not stay). Young are weaned at the age of 3-4 months. Observed census totals ranged from 33 animals in 1994 to 80 in 2005 (Table 1, Figure 2). Lobo de Rio (the River wolf), Los Lobos del Rio (Wolves of the River), Ariranha. It is also known as the Guiana flat-tailed otter, margin-tailed otter and winged-tailed otter. Reproductive suppression is likely to occur in giant otters, as only the dominant pair in each family breeds [4]. Successors were trained in census methodology in the field by the preceding census team, and the same field equipment was used. No, Is the Subject Area "Lakes" applicable to this article? The longest reproductive lifespan was 13 years for males and 11 years for females. For more information about PLOS Subject Areas, click Baseline demographic and reproductive variables, including survivorship; longevity; average age at dispersal; earliest and average age at primiparity; average litter size, frequency and seasonality; average reproductive lifespan; and variance in reproductive success are documented. Common name: Giant otter, giant Brazilian otter, giant river otter. spend significantly less time obtaining food than do smaller groups (5 inds. In areas of low human disturbance, such as Manu National Park, the characteristic behaviour of giant otter groups to investigate intruders ensures that the surveyor is usually not avoided, even by non-habituated groups (although transients are shy and more elusive). 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). The established territory is then marked by scent from the animals' anal glands. In that time, she experienced four pseudo-pregnancies [20], [28], [29]. In its lower stretches, the Manu is a lowland, white-water river, varying in width between 150 m and 200 m, with sandy beaches and frequent meanders. We studied population structure and genetic diversity of giant otters from Colombia’s Orinoco basin using analyses of … Next came the creation and implementation of large protected areas that contained remnant giant otter populations, including Manu. Ages were categorised as: ‘cubs’ up to 0.5 yr, ‘juveniles’ between 0.5 and 1.5 yr of age, ‘sub adults’ between 1.5 and 2.5 yr old, and ‘adults’ at and over 2.5 yr of age. Yes San Diego Zoo Global Peru, Department of Cusco, Cusco, Perú, Giant otters are towards the slow end of the fast-slow continuum in mammal life history strategies explored by Promislow & Harvey [35]. They do everything together and help each other to hunt food. First, a policy measure at the continental level was the 1975 listing of the giant otter in Appendix 1 of CITES. The total population of giant river otters in the wild could now be as low as 5,000. If typical, this suggests a pre census cub mortality of at least 30%. Each individual otter was noted as either resident (if already present in the study area in 1991 or 1999, or if born in the study area between 1991 and 2006) or immigrant, and labelled for each data point as positively identified, ID uncertain, or inferred. The family members clear an area beside a stream for their living quarters, of up to 50 sq meters, usually near feeding sites. Females are smaller at 1-1.5m (3.3-4.9ft). Individual reproductive success varied substantially and depended mainly on the duration of dominance tenure in the territory. As the river current erodes the bank, some meanders are cut off to form oxbow lakes, which can persist as distinct bodies of water for decades or centuries, but which remain connected to the parent river to varying degrees [32]. e106202. The average reproductive lifespan for adult females was 5.4 years (n = 30, SE 0.5, range 1.0–11.0), starting at age 3.0 which was the earliest recorded age of reproduction. In parallel with the recovery of some giant otter populations, however, protected areas such as Manu and other giant otter habitats of the Madre de Dios watershed have come under increasing pressure. Although some breeding occurs throughout the year, the peak of the breeding season is from late spring to early summer. This value of r implies a doubling time (derived from the equation for exponential growth Nt = No.ert by setting Nt/No = 2, and solving for t) of approximately 23 years, which is consistent with the overall trend observed in Figure 1. https://doi.org/10.1371/journal.pone.0106202.t003. Giant otters hunt opportunistically in non-ideal conditions, (for example, during the high-water period), or more selectively in optimal conditions [16], [24], [25]. The team’s studying several giant otter family groups both in a protected area, within Manu National Park, and areas outside the park that are … In Spanish, river wolf (Spanish: [lobo de río] error: {{lang}}: text has italic markup (help)) and water dog (Spanish: [perro de agua] error: {{lang}}: text has italic markup (help)) are used occasionally, though the latter has many other meanings) and may have been more … They can open their eyes after 1 month and start to regularly follow their parents out of the den. In order to identify individuals and classify them into age categories, we combined field observation of behaviour to establish status (whether cub, juvenile, sub adult, adult, or member of breeding pair), with subsequent review of video footage to establish ID and gender. Nature Services Peru, Department of Cusco, Cusco, Perú, The threats they face are numerous, and include habitat destruction, hunting for pelts, and conflict with fisherman, who often see the otter a… The area of lake encompassed by a territory predicts group structure: both the size of the groups and the fecundity of the breeding female are proportional to the total lake area within the group territory [unpublished]. PLoS ONE 9(8): At the time of censuses, cubs were aged approx. These are the longest recorded ages for free ranging giant otters. Thus, there has been a painfully gradual increase in the population of southern sea otters and according to a 2017 counting, these otters are numbered around 3,186. 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. From the life table (Table 3) we calculated the net reproductive rate Ro (∑lxmx), generation time T (∑xlxmx/Ro) and the intrinsic rate of increase r (ln (Ro)/T) for the Manu population, following Krebs [46] and Creel and Creel [13]. These otters are able to swim 330 feet (100 meters) in less than 30 seconds. As no surveys were conducted in 1997 and 1998, animals that were last seen in 1996 were assumed to have died in 1997. Unlike many other otter species, sexual dimorphism in giant otters is not pronounced: adult male total body length ranges between 1.5 to 1.8 m, while females are marginally smaller at 1.5 to 1.7 m. 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