Researchers studying fish in the Amazon River recently discovered a new species — and it carries an oddly familiar marking.

It helped the Amazon’s largest fish escape risk of extinction and is ... the pirarucu — also known as arapaima — historically have proven resilient to drought and climate change.

It lives only in the rivers and creeks of the Amazon, Orinoco ... and nostrils and ears that close in the water. Fish make up most of the giant otter's diet. They hunt alone or in groups ...