Sea otter mother and pup, Monterey Bay, California, USA

© Suzi Eszterhas/Minden Picture

Info. Sea otter mother and pup, Monterey Bay, California, USA

We’re in California's Monterey Bay, where a sea otter mother gives her three-day-old pup a place to snuggle and provides us with a very cute picture. The pups are totally dependent for about six months, so mum will carry them around on her stomach like you see here. When the little one does go into the water on its own, mum will rub the pup to fluff its coat, which causes the fur to retain air bubbles, insulating it from chilly water and causing the youngster to float like a cork.

That fur is remarkable – it's believed to be the thickest of any mammal on Earth, with around 100,000–400,000 hairs per square centimetre. After about four weeks, sea otter pups will start swimming and eating on their own – at six weeks they'll start diving by themselves, too. Until then, mum keeps them close. When she does have to leave a pup in search of food, she'll sometimes wrap the little one in kelp, which keeps it from floating away while she looks for dinner.