At last count, there are thirteen living species of otter on the planet. Many of us will no doubt be already familiar with the charismatically playful North American River Otter (Lontra canadensis), the wide-ranging Eurasian Otter (Lutra lutra), and dangerously adorable Sea Otter (Enhydra lutris). However of all thirteen, the largest – as well as one of the most in danger of someday lowering the total species count to twelve – is the enormous and very appropriately named Giant River Otter (Pteronura brasiliensis).