Otters are members of the mustelid family, alongside stoats, weasels and badgers. They have existed for around 30 million years and are semi-aquatic, meaning that they live both on and off land. Male otters are known as dogs, females are bitches and the offspring are pups.
There are 13 different types of otter, including river, sea, giant, African clawless and hairy nosed otter. Giant river otters are huge at over 1.5 metres in length. They are native to the Amazon and are also known as river wolves. Sea otters have paler faces and appear more fluffy than other otter species. They are well known for lying on their backs in kelp beds and using favourite stones to crack open shellfish.
Otters mostly eat fish and shellfish swimming below the surface in a snake-like undulating fashion. If you're watching otters you can trace their progress underwater by watching out for streams of bubbles on the surface. Otters do also eat red meat too, sometimes taking small birds and rabbits.
In murky waters where vision can be very limited, otters use their highly sensitive whiskers to detect their prey and it is also thought that they can smell by blowing bubbles from their nose and inhaling them back in.
Otters used to be heavily hunted for their fur, while in the UK the otter population took a major hit due to the use of pesticides, and its subsequent leaching into river systems. Conservation is very important to help otters survive and recent efforts have seen populations increase.