Think sea otters are just about whiskers and floating naps? There's much more behind those button eyes. In Prince William Sound, in Alaska, United States, they drift on ice or crack shellfish on their bellies with a favourite rock, as seen in today's image. Less obvious is how their taste for sea urchins helps protect kelp forests. Otters also depend on clean, cold water—their fur traps air for warmth rather than repelling water, making them highly vulnerable to oil spills.

India is home to three of the world's 13 otter species—Eurasian, smooth-coated and small-clawed. The smooth-coated is widespread, while the other two are confined to the Himalayas, areas north of the Ganges and southern India. All three thrive in the northeast and the Western Ghats, where they share habitats with gharials, crocodiles, Ganges river dolphins and freshwater turtles.