The Eurasian Otter Of Mainland, Orkney Islands, Scotland (Lutra lutra)
- The Persaud Foundation
- 2 days ago
- 8 min read
This month’s article series is going to be discussing the gorgeous & serene island of Mainland, also known as Hrossey or Pomona, located in the Orkney Archipelago of Scotland.
Mainland is an island located in the Orkney Islands Archipelago approximately 6 miles off the coast of Scotland. It is the largest island in the Orkney Archipelago, & the tenth largest island in the British Isles, at approximately 202 square miles. It holds the bulk of Orkney's population in its main settlement, Kirkwall, with a population of 10,020.
Known for its vast biodiversity of both terrestrial & marine life, peaceful coastal communities, & rolling green hills, Mainland is a picturesque island. One of the wonderful creatures that calls Mainland home, is the elusive Eurasian Otter.
The Eurasian Otter, also known as the European or Common Otter, is a species of otter distributed throughout Europe, Asia, & Northern Africa. It is the only otter distributed throughout Europe, making it rather distinctive. Individuals are often found near sources of water, such as estuaries, coastlines, creeks, & lakes. Fierce as they are, they are frequently seen catching fish & other underwater animals to consume, or occasionally birds, birds' eggs, other small mammals, & insects.
In today's article, we are going to be discussing the discovery & life of the Eurasian Otter, the mating strategies of the Eurasian Otter, the distribution of the Eurasian Otter, & the scientific details of the Eurasian Otter. With that being said, let us delve into this fascinating creature.
The Discovery & Life Of The Eurasian Otter
The Eurasian Otter was first described in 1758 by Carl Linnaeus in his book Systema Naturae. It is unclear how long this species has existed. With a total length of 40.2 to 54.2 inches (102 to 138 centimeters), a tail length of 12.6 to 22 inches (32 to 56 centimeters), & a weight of 8.1 to 24.3 pounds (4 to 11 kilograms), they are roughly comparable in size to a Borzoi puppy in weight. Their lifespan ranges from 3 to 10 years in the wild, to up to 22 years in captivity.
Eurasian Otters are rather intelligent, cunning, & nimble creatures. Unfortunately, there are no studies on the subject of Eurasian otter intelligence, in the wild, they are known to exhibit curiosity, inventiveness, & even use tools such as rocks to bash open shellfish. Their paws are surprisingly dexterous, & able to somewhat grip things.
As with most otter species, the Eurasian otter has a mild temperament, as they can be playful, as well as curious, yet also aggressive, & fiercely territorial. Individuals tend to be solitary, & prefer hunting alone as opposed to hunting in groups. When attempting to communicate with one another, they will use a wide range of clicks, chirps, squeaking, & whistling sounds. They will operate in 18 to 40 square kilometer areas (6.95 to 15.44 square miles), & will be fiercely protective of these lands. In these lands, they are known to build dens known as “holts”, in small cavities around riverbanks such as caves, rock spaces, tree roots, & similar locations. These holts often extend underground, & are lined with plant matter such as leaves. There may be one, or more in a single otter territory. In order to differentiate whose property is whose, they will mark their territory with the scent gland at the base of their tail, as well as their feces.
In the wild, they tend to be rather skittish, & not interact with people unless necessary. If humans are kayaking, swimming, boating, or otherwise occupying an area of water, they tend to stay away from said area. The fur industry values the Eurasian Otter for its pelt, showing they are of economic importance to humans. Unfortunately, as Eurasian otters will compete with fishermen, the Swiss Government historically put a bounty on them, with money distributed per individual killed. These bounties have since been lifted.
Eurasian otters are powerful swimmers, & have a swimming speed of approximately 6 to 7.5 miles per hour (10 to 12 kilometers per hour)! They swim by undulating their strong tail underwater, & using their hind legs as rudders, allowing them to propel themselves forward. They are very agile. As they are semiaquatic, & spend a fair amount of time on land, their running speed is up to 12 miles per hour.
During the day, or in some cases during the night, the Eurasian otters will sleep by curling up in their land-based holts, similar to a cat. It is not clear how they sleep on a biological level, or how long they sleep for each sleep cycle.
Eurasian otters are piscivores, meaning they primarily consume fish. Their diet consists of 80% fish, molluscs, crustaceans, amphibians, birds, & small mammals. They are usually nocturnal or crepuscular, though some populations in Scotland are known to be active during the day. To maintain their weight, they must consume an average of 1 kilogram (2.2 pounds), of food per day. They utilize their whiskers, also known as vibrissae, as sensing organs to monitor the movements of their prey, before striking. They are formidable predators. Natural predators include wolves, birds of prey, lynx, crocodiles, & sea eagles.
Individuals have dark brown fur covering their backs, legs, & head, & cream coloured stomachs. They have 2 layers of fur, one being a thick waterproof outer layer, which enables them to swim, & a second layer of warm inner fur. They are recognizable through their characteristic small eyes, rounded ears, dark snouts, webbed feet, & thick, strong tails.
Their last assessment by the IUCN Red List was on January 31st, 2020. Their status is currently listed as Near Threatened, with their population trend listed as decreasing. As of 2026, their number of mature individuals is estimated between 57,880, & 361,140.
The Reproductive Strategies Of The Eurasian Otter
The reproductive system of the Eurasian otter is polygamous. Individuals engage in sexual reproduction, & are not capable of asexual reproduction. They are not hermaphroditic, & exhibit gonochorism.
The average age of sexual maturity is 1.5 to 2 years, however, most Eurasian Otters will hold off mating until 2.5 to 3 years of age. Upon reaching the age of maturity, individuals will leave their parents’ territories to find their own. Males & females will communicate with one another via scent, through a communication center known as a latrine. Once a female & male have found one another, they will have an extended courtship. Once the time is right, they will copulate in the water, or occasionally on land. Mating seems to occur throughout the year.
After copulation, males will cease to have any involvement in the pups' lives. The female will gestate her young for 60 days, & give birth to a litter of 1 to 5 pups. The children are fluffy cream coloured, lack the ability to swim, & weigh approximately 100 grams. She will give birth in her holt, & will not allow her children to leave for 8 weeks. Her children will be nursed for these first few weeks, & at 8 weeks, she will begin weaning them on Upon their first venture outside of the holt, they will begin to acclimate themselves to the world around them. Eurasian otter pups tend not enjoy water on their first swimming attempt, which is likely due to their fluffy fur not being the best suited for swimming, & not being waterproof. Their waterproof coat begins growing in at 12 weeks, at which point they will become more comfortable with water.
The mother will lovingly tend to her pups for approximately 1 year, teaching them valuable skills in the process such as hunting, swimming, fishing, & bashing open shellfish. At this point, the pup will go off into the world to find its own territory, & become independent.
The Distribution Of The Eurasian Otter
The Eurasian Otter is a widely distributed species of Otter, from the Scottish Highlands to South Korea. They are commonly found in Europe, North Africa, & North Asia. Areas with streams, rivers, lakes, or coastlines, are appealing to them. In Europe, they are commonly found in Norway, western Spain, Portugal, southern Italy, Great Britain, & Ireland. In Asia, they are commonly found in the mountains of Syria, western India, the Himalayas, & western Nepal.
Unfortunately, due to their competition with fishermen, many viewed them as a nuisance, & they were driven extinct in Belgium, Switzerland, & the Netherlands. Thankfully, due to conservation efforts, populations have been expanding, & they are no longer extinct in these locations.
The Scientific Details Of The Eurasian Otter
Of all otter species, Eurasian otters are associated with having the most parasites, being associated with 184 species. One of the most common parasites is helminth worms.
Their phylum is Chordata, meaning that they developed these 5 characteristics all species under the phylum of chordata develop 5 similar characteristics either in adulthood or as juveniles. The characteristics that they develop include, a notochord, dorsal hollow nerve cord, endostyle or thyroid, pharyngeal slits, & a post-anal tail.
Their class is Mammalia. Mammalia is classified by the production of milk by the mother for their child to nurse, a neocortex which is a region of the brain, some capacity of fur or hair, & three middle ear bones. There are currently 6,400 species categorized under the class of Mammalia.
Their order is Carnivora, an order of mammals dedicated to carnivores. It is the sixth largest order for mammals at the time of publishing, with approximately 279 species. They are distributed across every major land mass.
Their family is Mustelidae, a family containing weasels, polecats, stoats, ferrets, ermines, martens, minks, wolverines, grisons, badgers, & otters.
Their genus, Lutra, is a genus of otters. Their binomial name is Lutra lutra.
Directories / Credits
Citation 1: “Lutra lutra”, Written by Susan Kennedy, & Published in 2003. Published by the Animal Diversity Web.
Citation 2: “Lutra lutra”, Written by Unknown, & Published at an unknown date. Published by the Otter Specialist Group.
Citation 3: “European otter”, Written by Unknown, & Published at an unknown date. Published by The Wildlife Trusts.
Citation 4: “Eurasian Otter (Lutra lutra)”, Written by Unknown, & Published at an unknown date. Published by the International Otter Survival Fund.
Citation 5: “Eurasian Otter Overview”, Written by Unknown & published at an unknown date. Published by the South Wales Otter Trust.
Citation 6: “European otter”, Written by Unknown, & Published at an unknown date. Published by Wildlife Online.
Citation 7: “Eurasian otter”, Written by Unknown & Published at an unknown date. Published by Animal Spot.
Citation 8: “Eurasian Otter”, Written by Loy, A., Kranz, A., Oleynikov, A., Roos, A., Savage, M. & Duplaix, N., & Last Updated on January 31st, 2026. Published by the International Union for the Conservation of Nature. https://www.iucnredlist.org/species/12419/218069689
Citation 9: “Reproduction”, Written by Unknown, & Published at an unknown date. Published by Otter Spotter.
Citation 10: “A systematic review of parasitic diseases of otters”, Written by Stacy R. Cotey, & Mason V. Reichard. Published by Frontiers.
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