Two species are marine; the others live mostly in fresh water. 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. The size of litters when at least one cub emerged averaged 2.1 (SE = 0.10, n = 14), and there was no evidence for a temporal trend (Pearson’s r = −0.26, P = 0.36, n = 14). In Brazil it is known as ariranha, from the Tupí word ari'raña, meaning water jaguar ((Template:Lang-pt). Gestation lasts 65-70 days and the altricial young are born in late August until early October. High dispersal mortality, especially among transient males, has also been documented in this study. No, Is the Subject Area "Peru" applicable to this article? The Giant otter, living in South America, and the largest of the otters in its total length, is the cousin of the sea and river otters in North America, Europe and Africa. Gestation is between 64 to 77 days [20], [26], [27], [28]. 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. Present demographic data from the first 16 years of a giant otter research and conservation project conducted in Manu National Park, south-eastern Peru. [41] found that total mercury levels in 68% of fish muscles exceeded the tolerable level for the European otter (Lutra lutra) and 17.6% exceeded 0.5 mg kg−1 fresh weight, the common standard for human consumption. Male giant otters can attain a length of 1.5-1.7m (4.9-5.6ft). 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. The species was listed as endangered in 1999 and the current population is about 5,000. These are the longest recorded ages for free ranging giant otters. Family groups are generally composed of a monogamous breeding pair and their offspring of several years, numbering 2–16 individuals [4], [5], [16], [18]. One of the attributes of life history variation affecting individual fitness is breeding tenure. As all suitable territories in Manu have now been occupied by resident groups and there are more non-breeding transients in the system, intraspecific competition is likely to increase in the future, with a consequent decrease in r. Male and female giant otters show very similar traits with respect to average ages at first litter (female 4.4 yrs, male 4.6 yrs. It is also known as the Guiana flat-tailed otter, margin-tailed otter and winged-tailed otter. ), average reproductive life-spans (female 5.4 yrs., male 5.2 yrs. The recovery of the Manu giant otter population has been assisted by a suite of conservation measures, acting at three spatial scales over the four decades. Because of their size and speed of swimming, Giant otters are successful competing for fish with Black caimans and jaguars. When members of a breeding pair of a similar, young age occupy a high quality territory, they have the potential for high reproductive success: the five most productive breeding pairs (defined as producing 10 or more cubs during their shared breeding tenure) produced at least 10, 11, 19, 21 and 25 cubs within their respective territories. Reproductive success is greater in territories with large areas of lake, where more young are produced, and are guarded and provisioned by non-breeding adults. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to 1.7 metres (5.6 ft). Unfortunately, this has become the most pressing question regarding the giant river otter. On average, breeding females produced 6.9 cubs per lifetime (se 1.17). Following the banning of fur trade, giant otter populations have recovered across South America. It lives only in the rivers and creeks of the Amazon, Orinoco, and La Plata river systems. The observed mean number of cubs born per resident group year (i.e. Entire litters could have been missed from the census if all their members died earlier. Inferred census totals ranged from 42 individuals in 1994 to 88 individuals in 2004 (Table 2). When they visit latrines, otters often defecate and urinate simultaneously [4] (fecaluria). Water pollution in the area due to mining has also significantly affected the giant otter population. One or two oxbow lakes form the core area or territory within each home range, maintained through defense and/or scent marking activities, and which hold resources critical to ensure successful reproduction. 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). Mortality is highest for cubs and for dispersing age classes. Breeding males produced a mean of 6.7 cubs per lifetime (SE 1.08). The babies are born blind and don’t start swimming until they are about 12 weeks old. https://doi.org/10.1371/journal.pone.0106202.g007, https://doi.org/10.1371/journal.pone.0106202.g008, https://doi.org/10.1371/journal.pone.0106202.g009. Hunting in the mid-1970s pushed giant otter populations to the brink of extinction. A further 13 cubs in 9 litters were inferred because they were identified as juveniles in the subsequent census. 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. A family has a home range of 12 sq. They can open their eyes after 1 month and start to regularly follow their parents out of the den. Partner compatibility (i.e. Lobo de Rio (the River wolf), Los Lobos del Rio (Wolves of the River), Ariranha. No invasive sampling methods were used and no giant otters were captured. Unfortunately, due to habitat destruction from logging, farming, and mining, the Giant Otter is near extinction, with a wild population … here. Although some breeding occurs throughout the year, the peak of the breeding season is from late spring to early summer. Yes The giant otter (Pteronura brasiliensis) is an endangered semi-aquatic carnivore of South America. first recorded as cubs in the study area) and estimated-age otters (first recorded as transients or as group members). The giant river otter ( Pteronura brasiliensis) is the largest member of the mustelid family, which includes otters, weasels, and ferrets, and are by far the loudest member of the group. The Madre de Dios floodplain is also a natural corridor through which giant otters of the Manu, Los Amigos, Heath and other tributaries could disperse. Brazil comprises roughly 3 quarters of the giant otter’s entire range. 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. Giant otters feed almost exclusively on fish [4], [6], [7], [16], [23]. The rate of expansion jumped from 2,166 ha per year before 2008 to 6,145 ha per year thereafter. These individuals probably died, since they were never seen again in the study area. This does not alter the authors’ adherence to PLOS ONE policies on sharing data and materials. In none of these cases was the male partner related to the philopatric female. The primary objective of the censuses was to count, identify, and record the status of all giant otters within the floodplain of the Manu River in order to determine population size and collect demographic data. Furthermore, in Manu National Park, lakes comprise a crucial and patchily distributed resource-rich habitat within a giant otter territory. broad scope, and wide readership – a perfect fit for your research every time. PLOS ONE promises fair, rigorous peer review, 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. The vulnerability of the Manu giant otter population to anthropogenic disturbance emphasises the importance of effective protection of core lake habitats in particular. 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. This species does not store food. The otter is lithe and slender with short legs, a strong neck, and a long flat tail that helps propel it gracefully through water. We therefore followed a similar approach to that adopted by Creel and Creel [13] for wild dogs. The data analysis for this paper was generated using [SAS/STAT] software, Version 9.12 of the SAS System for Windows 7, copyright 2002–2008. Yes 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. Yes Once otters become reproductively dominant, individual differences in breeding success depend principally on the duration of dominance tenure (Table S2), although breeding route may also play a role. The giant otter is the longest of the otter species but shares a similar weight with the sea otter. Hence, extrinsic factors such as territory quality and distribution may also limit r and explain why protected giant otter populations in Manu and elsewhere have taken decades to recover from the crash induced by over-hunting. Observations of captive individuals suggest that giant otters of both sexes reach sexual maturity at between 2 and 3 years of age [20], [22]. Females start dispersing as young as 1 year old but may stay on in their natal territories up to two years longer than males (6.5 years). … 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. In all cases (n = 11) when vacancies arose for a reproductively dominant female, it was a subordinate female otter from the oldest cohort that inherited the position, though she was not necessarily the only female in that cohort. They are seen within the Amazon, Orinoco and La Plata River systems and are found in slow-moving streams and rivers, lakes, swamps, and marshes, as well as flooded forest during the rainy season. The current total population is estimated to be somewhere between 1000-5000 individuals. Giant Otter was listed as endangered in 1999 and has a current population of about 5,000. Censuses were coordinated by Staib and Schenck between 1991 and 1996, by Groenendijk and Hajek between 1999 and 2005, and by Calvimontes in 2006. Frankfurt Zoological Society, Frankfurt, Germany, Affiliation Copyright: © 2014 Groenendijk et al. https://doi.org/10.1371/journal.pone.0106202, Editor: Alexander J. Travis, Cornell University College of Veterinary Medicine, United States of America, Received: April 16, 2014; Accepted: July 28, 2014; Published: August 27, 2014. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Citation: Groenendijk J, Hajek F, Johnson PJ, Macdonald DW, Calvimontes J, Staib E, et al. However, this study confirmed the existence of transient groups, fluid single- or mixed-sex associations of multiple non-breeding otters (up to 5 observed) that have not yet secured a territory and … the Manu floodplain is assumed to be neither a source nor sink population within the wider Upper Madre de Dios river ecosystem). Furthermore, of the giant otter reproductive pairs that produced litters, almost all did so only once per year, producing relatively small litters in those years when any cubs emerged (mean size = 2.1). 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). 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. Over all years, 67.9% of litters were born in the second quarter (beginning of the dry season) and 20.8% in the third quarter (end of the dry season). In total, northern La Paz Departmentis estimated to hold around 150 and 200 individuals, representing –together with giant otter populations in neighboring southwestern Pando Department and southeastern Peru- a population stronghold of regional importance for the conservation of this endangered species. These have focused on reducing human pressure on key habitats of the species, with the objective of maintaining habitat quality and maximizing giant otter reproductive success. Finally, regional and local habitat management measures such as Protected Area zoning and oxbow lake management plans have been implemented in Madre de Dios since 1990 [18]. However, in 2001, the same female in Cocha Salvador produced two litters (1+5 cubs) in one year. Frankfurt Zoological Society, Frankfurt, Germany, Affiliation Other studies [18], [33] suggest that the Madre de Dios River itself, twice as wide as the Manu River, provides the highest quality habitat for the species; its large oxbow lakes and wetlands could support large giant otter groups with high reproductive output and, potentially, the largest sub-population of the watershed. The dominant pair in each family produces a litter once a year and other adults do not breed [16], [18]. 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. Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The IUCN Red List has no current estimate for the total Giant otter population. (2014) Demography of the Giant Otter (Pteronura brasiliensis) in Manu National Park, South-Eastern Peru: Implications for Conservation. 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. San Diego Zoo Global Peru, Department of Cusco, Cusco, Perú, Yes Next came the creation and implementation of large protected areas that contained remnant giant otter populations, including Manu. Over the study period, the number of resident giant otter groups increased from a low of 7 in 1991 to a high of 12 in 2005. The population of giant otters were decimated and only 12 where left by 1971. The majority of the data analysed here were collected during 14 annual dry season censuses in Manu National Park between 1991 and 2006 (excepting 1997 and 1998). 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. We compared changes in habitat area and estimated giant otter population size between the reservoir pre- and post-filling stages. 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. 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]. Reproductive behavior has largely been documented by observations of captive animals. Reproductive suppression is likely to occur in giant otters, as only the dominant pair in each family breeds [4]. PJ received support from the Whitley Wildlife Conservation Trust (http://www.wwct.org.uk/) and the John Ellerman Foundation (http://ellerman.org.uk/). begging), sub adults and adults are more difficult to distinguish from each other. Routes to breeding are as follows: females can either inherit the dominant position in their natal group or they can form a new breeding group elsewhere. https://doi.org/10.1371/journal.pone.0106202.t002. No, PLOS is a nonprofit 501(c)(3) corporation, #C2354500, based in San Francisco, California, US, https://doi.org/10.1371/journal.pone.0106202. including years when a group was resident but no cubs emerged), was 1.5 (n = 117 group years). The giant otter has a handful of other names. Of the 17 cubs involved, 12 were subsequently recorded during the annual census. They build large dens in riverbanks and give birth to 1-5 babies at a time. All males have left their natal groups by age 4.5. Where more than one subordinate female was present in the oldest cohort, we could not determine the factor(s) that influenced which of the siblings became dominant. No, Is the Subject Area "Lakes" applicable to this article? Estimates have been provided for the following countries: 60 animals in Bolivia in the northwest in the Madre de Dios-Beni sub-basin; 50 individuals in 118,031 km² of the Pantanal (Paraguay river sub-basin), and 600 animals in the in 186,460 km² of the northeast (Itenez sub-basin), totaling an estimated 700 individuals; less than 250 animals in Ecuador; at least 200 animals in French Guiana; and 24-32 animals in Paraguay. Thus, the combination of (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 a pre-census cub mortality of 30%, (4) a further 50% mortality up to age of dispersal as well as high mortality amongst dispersers (especially males), (5) plus the influence of breeding pair compatibility, all help to explain the low intrinsic rate of increase of the population, slowing its ability to recover from the pelt trade in the past or possible future disease outbreaks. Mean annual observability for both resident and transient otters was calculated by dividing the observed census total by the inferred total for that year. 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. Adult males weigh between 23 and 32 kg and females between 20 and 29 kg [4], [7], [19]. Although widely distributed on a continental scale, overall they may occupy less than 5%, often less than 1% of a given watershed. 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. Between 1950 and 1970, Peru, Suriname and Venezuela duration of dominance tenure in the wild per group... Promises fair, rigorous giant otter population review, broad scope, and the population. And anacondas your research every time [ 28 ] pets, and have higher fish capture rates 16! Been documented with distinct sounds indicating aggression, alarm and reassurance Conservation Trust ( http: //www.wwct.org.uk/ and! Argentina and Uruguay, and La Plata river systems its fur predator in river. 13 years for males and 11 years for males and 11 years for and... 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