Reproductive behavior has largely been documented by observations of captive animals. including years when a group was resident but no cubs emerged), was 1.5 (n = 117 group years). Giant otters are towards the slow end of the fast-slow continuum in mammal life history strategies explored by Promislow & Harvey [35]. 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. https://doi.org/10.1371/journal.pone.0106202.s002, https://doi.org/10.1371/journal.pone.0106202.s003. 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. Frankfurt Zoological Society, Frankfurt, Germany, Affiliation One of the few strongholds of giant otters now lies in the Cantao state park wetlands that nestle between the Amazon rainforest and the … Giant otters produce 9 different vocalizations and are very loud. Incest was never recorded. 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]. Only 11.3% were born during the wet season (first and fourth quarters combined). This species was excessively hunted up until the late 1970s for its valuable fur. 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. In two cases, however, dominant females were displaced by another female in the group (a sister and a daughter). One of the attributes of life history variation affecting individual fitness is breeding tenure. Gestation lasts 65-70 days and the altricial young are born in late August until early October. Observed group size ranged from 2 to 13, with a mean of 6.0 (n = 117). 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. The otter is lithe and slender with short legs, a strong neck, and a long flat tail that helps propel it gracefully through water. The 1990 IUCN Action Plan for Latin American Otters [12] stated that: “The giant otter’s range has been greatly reduced and its diurnal, social habits, along with its size (and consequent pelt value) make it exceptionally vulnerable; the species is severely threatened” and continued to specify that, for Peru, a conservation priority was to “Monitor closely the main identified populations, particularly the giant otters of Manu National Park…” and to “Develop techniques for accurate census-taking….” This study was initiated to respond to these needs. 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]. Giant otters were very nearly extinct by the 1970s. The species is also found in Bolivia, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname and Venezuela. 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]. It is also known as the Guiana flat-tailed otter, margin-tailed otter and winged-tailed otter. Yes They can open their eyes after 1 month and start to regularly follow their parents out of the den. We present data on 30 adult females (15 known-age, 15 estimated-age) and 31 adult males (10 known-age and 21 estimated-age) which reproduced successfully, i.e., producing at least one litter to age 0.5 years. Observations of wild and captive otters suggest that giant otters are weaned at approx. Two species are marine; the others live mostly in fresh water. We compared changes in habitat area and estimated giant otter population size between the reservoir pre- and post-filling stages. Each year, therefore, several dominant females failed to raise a litter to 0.5 years. 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. Becoming an extra-group breeder was not observed. 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. 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. spend significantly less time obtaining food than do smaller groups (5 inds. 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. 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. 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. They take a nap at mid-day during really warm weather. Citation: Groenendijk J, Hajek F, Johnson PJ, Macdonald DW, Calvimontes J, Staib E, et al. Pseudo-pregnancies are common in captivity [20]; for example, in Cali Zoo, Colombia, the reproductive activity of a pair was monitored for 5 years with the female giving birth to nine litters. Wildlife Conservation Research Unit, University of Oxford, Abingdon, Oxfordshire, United Kingdom, If giant otters seen in an earlier census were not observed in subsequent surveys, they were considered dead. The IUCN Red List classifies the giant river otter as endangered, with its population still decreasing. 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). Of the 17 cubs involved, 12 were subsequently recorded during the annual census. The primary cause for this population decline was poaching for otter pelt. Analyzed the data: JS FH PJ. Between 1950 and 1970, Peru alone exported 20,000 pelts, and in the 1960s, 20,000 pelts were exported from Brazil. Gold mining in the area has also been shown to affect giant otters as mercury was found in many of their bloodstreams (mercury is a byproduct of gold mining). On average, breeding females produced 6.9 cubs per lifetime (se 1.17). Sizeable burrows are then built under fallen logs. As a norm, the dominant female of a giant otter group produced one litter per year. Despite this, almost two decades later, in 1993, the species was upgraded from ‘Vulnerable’ to its current ‘Endangered’ IUCN Red List status [11]. The IUCN Red List has no current estimate for the total Giant otter population. Partner compatibility (i.e. 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 … Approximately 50% of the Manu population consisted of cubs and juveniles and this varied little over time (Figure 4). If intruders invade the family's territory, the parents will defend it and their family members. The number of litters produced annually in the study area increased significantly over the study period (Pearson’s r = 0.63, P = 0.01) (Figure 5). Its thick, velvety brown fur has characteristic white markings around the neck. The threats they face are numerous, and include habitat destruction, hunting for pelts, and conflict with fisherman, who often see the otter a… In that time, she experienced four pseudo-pregnancies [20], [28], [29]. This species is a native of South America (except for Chile), east of the Andes. 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 … In 11 instances the breeding male disappeared and was replaced by an immigrant adult male. The giant otters are mostly found in South America and are common along the Amazon River. first recorded as cubs in the study area) and estimated-age otters (first recorded as transients or as group members). Although widely distributed on a continental scale, overall they may occupy less than 5%, often less than 1% of a given watershed. Endangered giant otters, Pteronura brasiliensis, are found along the Amazon and Orinoco rivers and most of their tributaries. Annual mean resident group size increased slightly over the study period; this was statistically significant (Pearson’s r = 0.56, P = 0.03) (Figure 3). Breeding males produced a mean of 6.7 cubs per lifetime (SE 1.08). San Diego Zoo Global Peru, Department of Cusco, Cusco, Perú, 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). These otters are able to swim 330 feet (100 meters) in less than 30 seconds. The established territory is then marked by scent from the animals' anal glands. 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. Giant otters are Of 50 reproductively mature males, 19 (38%) were not recorded to produce a single litter, 16 (32%) produced only one or two litters, and 15 (30%) produced three litters or more. At 9-10 months they can hunt independently and look just like their parents. It lives only in the rivers and creeks of the Amazon, Orinoco, and La Plata river systems. Transient group size ranged from 2 to 5, with a mean of 2.9 (n = 16, se = 0.22). Frankfurt Zoological Society, Frankfurt, Germany, Affiliations 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). Immigrants were only recruited into a resident group if they claimed the dominant breeding status. As of now, 5000 giant otters are left in the world. 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