They are one of the most adaptable creatures in the animal kingdom. How many of you have opened your eyes underwater and not been able to see a thing other than a blurred mess. Not so with Otters, they can see out of the water and as soon as they jump into the murky depths a muscle behind their eye lens tenses and changes the focus of their eyes so they can see perfectly under water. Clever little things. They are actually members of the weasel family which also includes badgers, minks, polecats and wolverines but, needless to say, none of them can focus their eye-sight under water in the same way.
The programme we saw was called Supercharged Otters and is on BBC iPlayer until the 20th August if you want to watch it. The programme features cameraman Charlie Hamilton James who has been captivated by otters for the last 25 years. He’s filmed them more than anyone else and now, through the eyes of three orphaned river otters, a set of ground breaking experiments and some incredible wild encounters, Charlie reveals their survival secrets and exactly why he believes they’re so special.
A new-born pup is not just cared for by the mother but the whole family. The mum, the dad and even older offspring all help out. Female otters reach sexual maturity at approximately two years of age and males at approximately three years. The home (a holt) is built under tree roots or a rocky cairn, more common in Scotland. It is lined with moss and grass. After one month, the pup can leave the holt and after two months, it is able to swim. The pup lives with its family for approximately one year. Otters live up to 16 years; they are by nature playful, and frolic in the water with their pups. Its usual source of food is fish, and further downriver, eels, but it may sample frogs and birds too.
They have long, slim bodies and relatively short limbs. Their most striking anatomical features are the powerful webbed feet used to swim, and their seal-like abilities holding breath underwater. Most have sharp claws on their feet and all except the sea otter have long, muscular tails. The thirteen species range in adult size from around two foot to around six feet in length and from around two-and-a-half pounds up to around a hundred pounds in weight. The Asian small-clawed otter is the smallest otter species and the giant otter and sea otter are the largest. They have very soft, insulated underfur, which is protected by an outer layer of long guard hairs. This traps a layer of air which keeps them dry, warm and somewhat buoyant under water. It is the thickest fur in the animal kingdom with around a million hairs per square inch!
Several otter species live in cold waters and have high metabolic rates to help keep them warm. European otters must eat 15% of their body weight each day, and sea otters 20 to 25%, depending on the temperature. In water as warm as 10°C, an otter needs to catch 3.5oz of fish per hour just to survive. Most species hunt for three to five hours each day and nursing mothers up to eight hours each day.
For most otters, fish is the staple of their diet. This is often supplemented by frogs, crayfish and crabs. Some otters are experts at opening shellfish, and others will feed on available small mammals or birds. Prey-dependence leaves otters very vulnerable to prey depletion. Sea otters are hunters of clams, sea urchins and other shelled creatures. Their ability to use stones to break open shellfish on their stomachs does not come naturally and the skill must be learned by the young.
Otters are active hunters, chasing prey in the water or searching the beds of rivers, lakes or the seas. Most species live beside water, but river otters usually enter it only to hunt or travel, otherwise spending much of their time on land to prevent their fur becoming waterlogged. Sea otters are considerably more aquatic and live in the ocean for most of their lives.
Otters are playful animals and appear to engage in various behaviours just for sheer enjoyment, such as making waterslides and then sliding on them into the water. They may also find and play with small stones. Different species vary in their social structure, with some being largely solitary, while others live in groups – in a few species these groups may be fairly large and include many members of the same family.
For many generations, fishermen in southern Bangladesh have bred smooth-coated otters and used them to catch fish. Once a widespread practice, passed down from father to son throughout many communities in Asia, this traditional use of domesticated wild animals is still in practice in the district of Narail, Bangladesh.
Here at Jammy Toast we have become admirers of otters and if you watch Supercharged Otters on BBC iPlayer I am sure you will do too.