Giant Otter
Pteronura brasiliensis
Silhouette: Margot Michaud · PhyloPic
- KingdomAnimalia (Animals)
- PhylumChordata (Chordates)
- ClassMammalia (Mammals)
- OrderCarnivora (Carnivorans)
- FamilyMustelidae (Mustelids)
- GenusPteronura (Giant Otters)
- SpeciesPteronura brasiliensis (Giant Otter)
In 3 days ~60% in a week ~90%
About the Giant Otter
The giant otter or giant river otter (Pteronura brasiliensis) is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, reaching up to 1.8 m (5 ft 11 in). Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.
The giant otter ranges across north-central South America; it lives mostly in and along the Amazon River and in the Pantanal. Its distribution has been greatly reduced and is now discontinuous. Decades of poaching for its velvety pelt, peaking in the 1950s and 1960s, considerably diminished population numbers. The species was listed as endangered in 1999 and wild population estimates are typically below 5,000. The Guianas are one of the last real strongholds for the species, which also enjoys modest numbers – and significant protection – in the Peruvian Amazonian basin. It is one of the most endangered mammal species in the Neotropics. Habitat degradation and loss is the greatest current threat. They are also rare in captivity; in 2003, only 60 giant otters were being held.
The giant otter shows a variety of adaptations suitable to an amphibious lifestyle, including exceptionally dense fur, a wing-like tail, and webbed feet. The species prefers freshwater rivers and streams, which are usually seasonally flooded, and may also take to freshwater lakes and springs. It constructs extensive campsites close to feeding areas, clearing large amounts of vegetation. The giant otter subsists almost exclusively on a diet of fish, particularly characins and catfish, but may also eat crabs, turtles, snakes and small caimans. It has no serious natural predators other than humans, although it must compete with other predators, such as the Neotropical otters and various crocodilian species, for food resources. Wikipedia →
Sounds
Alarm call0:14
Ecuador · 2026
© Simon Elliott · XC1092129 · CC BY-NC-ND 4.0
Alarm call0:14
Ecuador · 2025
© Marc Anderson · XC979833 · CC BY-NC-ND 4.0
Recording0:21
Peru · 2024
© Hubert Szczygieł · iNaturalist · CC BY-NC 4.0
Recent sightings of Giant Otter in Cuyabeno Wildlife Reserve
LIVEiNaturalistGlobal Distribution
Parks Where Found
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Parque Estadual Encontro das Águas | 🇧🇷 Brazil | |
| 2 | Yasuní National Park | 🇪🇨 Ecuador | |
| 3 | Manu National Park | 🇵🇪 Peru | |
| 4 | Tambopata National Reserve | 🇵🇪 Peru | |
| 5 | Cuyabeno Wildlife Reserve | 🇪🇨 Ecuador |
Zoos & Centres Where Found
Closest Relatives at Cuyabeno Wildlife Reserve
Before you go
What are the chances of seeing a Giant Otter in Cuyabeno Wildlife Reserve?
Possible
About 30% of wildlife watchers report a Giant Otter sighting in Cuyabeno Wildlife Reserve on a given day, based on 14 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 12th most-seen of the 19 mammals we can rate there. Over three days the chance rises to about 60%, and over a week to about 90%, if each day is a fresh chance.
When is the best time to see a Giant Otter in Cuyabeno Wildlife Reserve?
June and December
In those months about 40% of wildlife watchers report a Giant Otter in Cuyabeno Wildlife Reserve on a given day, against under 5% in July and September, the lowest months.
What time of day is best to see a Giant Otter?
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Giant Otter sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Is Cuyabeno Wildlife Reserve the best place to see a Giant Otter?
5th of 5
Of the 5 parks where we can rate Giant Otter sightings, Cuyabeno Wildlife Reserve ranks 5th at about 30%. The best odds are in Parque Estadual Encontro das Águas (Brazil, about 90%), Yasuní National Park (Ecuador, about 30%) and Manu National Park (Peru, about 30%). All parks ranked.
Where does the Giant Otter sighting chance come from?
GBIF citizen-science records
It is estimated from how often the Giant Otter is recorded against all the mammals logged in Cuyabeno Wildlife Reserve (14 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
