WRW #22: Spot the Otter!?
The cache is hidden at the sculpture of this wonderful 'weasel of the water' which, if you keep your eyes peeled, you may be lucky to spot as you walk along the river trails as, although elusive, they are regularly seen along the banks.
***Please replace carefully - do not push too far in - lid level with the concrete base edge - and use the stickoflage to hold it in place - thanks!***
To reach the cache location: park in the parking area @ N 53 56.874 W 1 52.595 then head north following the Dales Way path into and through the Olicana cottages & mobile home site where the sculpture is located. Thanks are due to the management for kind permission to place the cache.
The common or Eurasian (river) otter (Lutra lutra) is a semiaquatic mammal native to Eurasia. It is a mustelid and the widest distributed member of the otter subfamily (Lutrinae) of the weasel family (Mustelidae). It is endangered in parts of its range, but recovering in others.
It is very well adapted to the aquatic environment, with short strong limbs, webbed feet and claws, and highly sensitive whiskers ('vibrissae'), enabling it to detect prey in murky waters. Its sense of sight, smell and hearing is acute. The position of the eyes high on the head allow it to see out of the water whilst the rest of the body is below. The thick fur is made up if 2 layers, a thick outer waterproof one protecting a warm inner one. The fur traps a layer of air to enable insulation.
When underwater the otter can close its ears and nose. Although it is an excellent swimmer and hunter of fish, it can only hold its breath for a short time, most dives average at about 30 seconds. As the cubs are not natural swimmers, hindered by their fluffy coats, they are often dragged to the water by the mother at about 16 weeks of age, after which their swimming and hunting skills develop rapidly.
Its vocalisations include a high-pitched whistle between a female and her cubs, and various twittering noises.
It is 57-95cm plus a tail of 35–45cm with the female shorter than the male. It weighs 7-12kg but old males 
may reach 17 kg or more. Typical lifespan is 17 years.
Their varied and adaptable diets mean they may inhabit any unpolluted body of fresh water, including lakes, streams, rivers, and ponds, as long as the food supply is adequate. They may also live along the coast, in saltwater, but require regular access to freshwater to clean their fur.
It eats mainly fish but during winter and in colder environments, consumption is much lower and it eats other food including amphibians, crustaceans, insects, birds and sometimes small mammals!
It is very territorial and lives mostly alone. Its territory is between 1-40km long (average ~18 km) depending on the density of food available and the width of the water suitable for hunting (it is shorter on coasts, where the available width is much wider, and longer on narrower rivers).
It uses its feces, spraints, to mark its territory and prioritize the use of resources to other group members. Mating takes place in water and can occur at any time of the year - most likely determined reproductive maturity and physiological state.
Female otters become sexually mature between 18-24 months old and the average age of first breeding is found to be 30 months. Gestation takes 60-64 days with the litter (1-4 pups) weighing about 10% of the female body mass and dependent on the mother for about 13 months.
The male plays no direct role in parental care, although the territory of a female with her pups is usually entirely within that of the male. Hunting mainly takes place at night, while the day is usually spent in the holt (den) – usually a burrow or hollow tree on the riverbank which can sometimes only be entered from underwater.
Though long believed hunt by sight and touch only, they may also be able to smell underwater!
It declined across its range in the second half of the 20th century, mainly due to pollution from pesticides 
such as organochlorine and polychlorinated biphenyls. Other threats included habitat loss and hunting, both legal and illegal.
Populations are now recovering in many parts of Europe. In the United Kingdom, the number of sites with an otter presence increased by 55% between 1994 and 2002. In August 2011, the Environment Agency announced that otters had returned to every county in England since vanishing from every county except the West Country and parts of Northern England.
Recovery is partly due to a ban on the most harmful pesticides that has been in place across Europe since 1979, partly to improvements in water quality leading to increases in prey populations, and partly to direct legal protection under the European Union Habitats Directive and national legislation in several European countries.
For more information see here. See short videos here, here, here (eating a chick), here (series of short clips and here (cubs playing in water).