Found only in South America, Giant otters, or Pteronura brasiliensis, are the largest otters in the world, with some as long as 6 feet. They are also the rarest otters in the world, with only a few thousand believed to be surviving in the wild. Sometimes known as the “river wolf,” their fur is chocolatey brown and extremely soft. They also have a creamy white patch on their throat that is unique to each otter, Meg Symington, managing director of the Amazon for WWF, told Business Insider.
“They are extremely smart animals, and sort of like wolves or lions, they can be cooperative hunters. They live in groups and they hunt fish together as a group, herding the fish,” she said. “They’re active during the day, so they’re actually a large mammal that you can see easily in the Amazon, which is unusual since a lot of large animals are hard to see in the jungle.”
Historically, giant otters were hunted for their pelts, causing a huge decline in their numbers. While they are no longer hunted today, they remain endangered because many of their aquatic habitats (rivers and lakes) have been degraded and destroyed, causing the fish populations they rely on for food to dwindle. They are many times viewed as nuisances by humans, especially by fishermen. They are also threatened by gold-mining in the region, which leads to mercury poisoning. “Because they are an apex predator, they accumulate mercury because they eat so much fish,” Symington explained.
(Photo by Mark Newman via Getty Images)