The River Wolf

_KS_4454As mentioned in the previous post, Lake Sandoval is an oxbow lake that was formed from the Madre de Dios River untold decades ago.  The creation of Lake Sandoval also provided the perfect habitat for one of the most endangered and rarest creatures of the rainforest, the Giant River Otter.  Originally, this was a common species but now there are only 5,000 Giant River Otters left in the wild throughout South America after decades of being hunted, deforestation and generally being disturbed by human activity.  Peru is a world leader in designating protected areas for their extraordinary biological diversity and includes the Tambopata National Reserve which is one of the few accessible places on earth where the Giant River Otters can be observed in their natural habitat.

The Giant River Otter is also known as a river wolf and water dog although these names were more commonly used in the reports of explorers from the 19th and 20th century.  They are the largest of the Mustelidae family of mammals which includes badgers, ferrets,  martens, otters, weasels, and wolverines and typically reach a length of five feet or more than one and a half meters.

Their cream-coloured throat patch is unique to each otter and is how scientists can differentiate each individual mammal.  The Otters can often be ‘periscoping’ by sticking and it is believed that this not only allows them to see potential danger but also identify other Otters by their throat patch.


Giant River Otters are expert fishers and eat a wide variety of fish and as you can see in the images, eels as well.  Giant Otters are very social and will do almost everything together including fishing and playing.  They also have webbed feet, water-repellent fur to keep them dry and warm, and nostrils and ears that close in the water.  The Giant River Otter also has highly sensitive whiskers which allow the animal to track changes in water pressure and currents, which in turn aids in detecting prey.

Lounging on a log - great view of webbed feetLounging on a log - view of teeth and feetFamily shotFamily shot 2You looking at me?Side viewAnother sideviewNuzzlingReturn nuzzleFinishing off lunchOut for a swimEatingMore eatingChomping on an eel 1Chomping on an eel 2Chomping on an eel 3May I have some too?

It is not always a guarantee to see the Otters of Lake Sandoval since the lake is fairly large and they use its entirety to hunt, fish and play.  However, on one of our early morning excursions, we were most fortunate to spend some time with them in their daily activities.  I trust that you will enjoy the images and maybe one day see them for yourself.


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  1. Andy Stinnissen December 11, 2013 at 5:10 pm #

    The “lounging on a log” photo also shows the webbed feet and flattened tail of this rare species. Great pictures Arni – thanks for sharing them with us.

    • Arni December 11, 2013 at 9:29 pm #

      Thanks Andy, those feet are quite incredible and no wonder fish don’t stand a chance. It was quite a thrill to spend some time watching them.

  2. Scott Martin December 14, 2013 at 12:46 am #

    Thanks for such an informative post about the River Wolf Arni, which I’m sure you were thrilled to see from such close range. My favourite image is 2/17, where he is posing like the River King showing off his tail, webbed feet and sharp teeth. Its nice to see that such a tough looking animal has a softer side that you’ve captured perfectly in 9/17. Superb work as always Arni.

    • Arni December 15, 2013 at 7:15 pm #

      It was quite something to see the Giant River Otters for sure. We saw them twice and we were able to view them for about 20 minutes each time. As for your favourite image, one of the adults climbed on that log for just a few minutes and only once. We were a fair distance away and I was able to get the shot with the 5DMKIII and 70-200 so cropping wasn’t a problem 😉