Tuesday, May 11

Elusive mammals – otters

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RECENTLY, a British newspaper published an article entitled, ‘Elation over otter spotted in city river’. Such a rare occurrence at Adelphi Weir in Salford, Manchester delighted local residents and some conservationists rejoicing that British waterways are recovering from pollution. However, other conservationists and anglers were not happy to see such rapacious predators of fish, ducklings, and little birds so near to them.

The otter population in England fell sharply and steeply between the 1950s and 1970s owing to the use of pesticides on agricultural land leaching into streams as well as through hunting. It was but a few weeks ago, whilst walking my dog that I came across an otter hunt along the banks of my local river. My dog bristled and shook to see so many pack animals but to my relief they ignored her for they were on the scent of an artificially laid trail.

The hairy-nosed otter is one of the rarest and least observed of otter species.

I must admit that I feel guilty for in my possession is my late grandmother’s broach – none other than an otter’s paw mounted on a pure silver clasp! In late Victorian times my grandfather joined a Pembrokeshire otter hunt and gave the broach to my grandmother as a wedding present! In 1975, UK legislation brought a halt to otter hunting and subsequently the otter population has significantly increased.

 

European otter (Lutra lutra)

This otter is the largest British member of the weasel family. With its long, sleek, stream-lined physique, and tiny ears, a broad muzzle and a thick muscular tail, it is a formidable animal. It uses its tail as a rudder and with five webbed toes and close cropped chocolate brown waterproof coat which becomes spikey and charcoal grey when wet. It is a true river dweller of quintessential English waterways. When diving for fish, it can shut its ears and nostrils. Estuarine otters have to frequently move upstream to renew the oil in their fur.

An otter grows in bodily length to 0.8 metres and a tail-length of 0.51metres. Their decline was carefully documented in the 1950s and 1960s through habitat loss and the use of organochlorine pesticides together with the work of river authorities in removing riverside vegetation to increase water-flow, thereby depriving otters of suitable places for their holts.

 

Distribution

A European otter takes a break on a rock.

Otters are common occupants in rivers in Southwest England, East Anglia, Northwest England, Wales, and Scotland and are travellers over many kilometres. It is sometimes forgotten that otters live also in coastal estuaries such as the one that my grandparents lived in Pembrokeshire, Southwest Wales. In such locations they feed on coarse fish such as eels, salmon, trout, and other sea fish. They have a particular penchant for crayfish, crabs, and small mammals, frogs, and very small waterfowl.

Near to my home in Somerset, the River Otter rises in the Blackdown Hills and meanders its way to the sea through the villages of Otterford, Ottery St Mary, Upottery, and Venn Ottery.

 

Breeding

There is no definite breeding season and two to four cubs can be born in any month of the year in a breeding nest or holt. A holt is but a tunnel amongst tree roots, a hole in a riverbank, or a hollow in a fallen tree. Usually, one litter occurs annually and the bitch stays with her young until the next mating season. Both the dog and the bitch make excellent parents and enjoy playing with their cubs. The parents’ partnership is but temporary, for as soon as the cubs are old enough to look after themselves the dog otter takes off to live by himself.

 

Clues to otter territories

Tracks and droppings (spraits) are the best clues that otters are around. The tracks of their presence are marked by four-toed lopsided imprints in the mud and sand whereas their spraits are deposited in carefully selected spots, which will be seen by other otters. These act as ‘keep out’ territorial warnings and are left on boulders or in sheltered places not to be destroyed by the sun or rain or on sandcastles scrapped up by the otter.

 

Threats to humans

Often they are found near lakes and reservoirs stocked with fish. Otters bred in captivity and then released into the wild are a great threat to trout and salmon fisheries and in one reported instance a high percentage of organically reared trout were destroyed by this voracious mammal’s appetite. Humans are, however, a greater threat to otters’ habitats.

 

Hairy-nosed otter (Lutra sumatrana)

This mammal, living in selected places in Southeast Asia, is one of the rarest and least observed of otter species. With short brown fur which becomes paler on its underside, it has a white upper lip and chin and prominent and webbed claws. Its cheek areas are covered with short hairs or whiskers and its bodily length averages 0.7 metres and its tail length of 0.43 metres and weighs, on average, 6.5kg.

 

Whereabouts

The hairy-nosed otter ranges throughout Southeast Asia from Cambodia, Malaysia, Sumatra and Kalimantan in Indonesia, southern Vietnam, and Thailand. Several individual sightings have been reported in the Tabin Wildlife Reserve in Sabah. Its habitats vary from estuarine locations to larger inland rivers, feeding on walking catfish, snakehead water snakes, climbing fish, crustaceans, and molluscs. Owing to climate change, its main source of food is through foraging and thus these otters may be found closer to kampungs.

 

Rarest otter species in Asia

This species is verging on extinction mainly due to the loss of its lowland wetland habitats, hunting for otter skins as well as accidental trapping in fishermen’s nets. It remains on the International Union for Conservation of Nature (IUCN) Red List of Endangered Species. So very little is actually known about this very elusive creature.

Sea otters are quite a different kettle of fish-if you will excuse the pun – and another article will be devoted to them. Rest assured, otters are very elusive and should you come across a sighting and even photograph one, do let your local wildlife experts know. In this way we can keep track of these precious animals before they become extinct or through legislation, continue to fascinate us.