How Stean Blog February 2016 Otters
Otters – Lutra lutra
We have only one species of otter in the UK; the sea otter is the same species as the one that inhabits our rivers and which visits How Stean Gorge, indeed probably lives there. Do you know of a holt, an otter’s home, in Upper Nidderdale? You need to be careful because at first otters can be confused with mink so here’s a few pointers. Otters have “milk chocolate brown fur (darker when wet) with a slightly pale underside, a long slender body and long thick tapering tail, and small ears on a broad head. Adults are often a metre or more in length. They swim low in water with the top of the head and back only just visible and a V-shaped bow wave. When walking/running on land they have a marked ‘hump-back’ appearance”. American mink Neovison vison on the other hand have “plain chocolate brown/black fur (black when wet) with a white chin. They have variable white patches on throat, chest and groin and a fluffy tail about half the length of the body. It is a similar size to a polecat but much smaller than the Eurasian otter, as it is only 60cm in length. A mink swims with about half the body above the water. Its face has a slightly pointed muzzle.” Download a printable field sign guide for otter and mink from The Mammal Society. It used to be said that mink displaced otters, now it is believed that the opposite is true and otters keep mink off their territory. You only have to look at the size differences to work out which is the most likely truth.
Otters’ main prey is fish and that provides some difficulties as unlike other mammals they can’t use smell as an aid because they have to keep their nostrils closed whilst underwater. One of the ways you can tell if they are around is by looking for spraints (piles of poo) which contain mainly fish shells, bones, shells of crustaceans, feathers or fur. Those with a keen sense of smell may be able to detect a fishy smell emanating from this tiny pile, although maybe a keen sense of smell isn’t the best attribute under the circumstances. Your chances of seeing an otter will increase if you go looking at dawn or dusk. Around this time of year male otters will get that urge to maintain the species and they can do this by climbing over the watershed to new territories. They follow the stream course as far as possible and what better route than to follow the stream through How Stean Gorge? They also need to eat on the way and their journey may well coincide with the time frogs come out of hibernation, so if you see what looks like the insides of an animal perhaps with uneaten spawn you may well have discovered the latest meal of a travelling otter.
I’m pleased to say that otter numbers have increased over recent years and it is probable that our waterways, especially lower down the dale, are nearing their maximum capacity and whilst that may not please all the fishermen, some of whom have had to resort to electric fences to keep the animals out of some lakes, seeing an otter is a delight for most folk and one good place to see them is Yorkshire Wildlife Trust’s Staveley Nature Reserve.
Yorkshire Wildlife Trust (YWT)
Nigel Heptinstall (Outdoors2015)