It is no surprise that an isolated island group like Shetland has a very restricted terrestrial mammal list - approximately a quarter of the number of species found on Mainland Britain have been recorded in Shetland. All of these have been introduced by humans at some time in the past - indeed the only native Shetland mammals are the Grey and Common Seal. The following are accounts of all known species of terrestrial mammals to have occurred in Shetland. The records are as complete as possible but details of any omissions or additions would be welcomed.
Hedgehog (Erinaceus europaeus)
A relatively recent Introduction to Shetland recorded by both Harvie-Brown (1892 & 1893) and Evans & Buckley (1899) who indicate that the species was introduced in about 1860, or slightly earlier by the farmer at Veensgarth, Tingwall (central Mainland). Any subsequent introductions are unrecorded as the species apparently spread rapidly from the initial introduction and is now widespread on Mainland and most of the inhabited islands except Out Skerries. Hedgehogs were also introduced onto Fair Isle and Foula but are now thought to be extinct on former.
Rabbit (Oryctolagus cuniculus)
The date of introduction into Shetland of this species is not known although the first mention of the species in the literature reports that Rabbit warrens were present on the West Isle, Burra (at the holes of Minn and at the Links of Meal), and on the isles of Oxna, Hildasay and Papa Little in 1654 (Leigh 1908). Thereafter it was reported as widely established on links and holms in Shetland by about 1680 and Evans and Buckley say that the species was introduced on Foula in about 1879. Today the Rabbit is widespread and numerous on Mainland and most inhabited islands as well as the majority of uninhabited islands.
Brown Hare (Lepus capensis)
The species was introduced to Shetland at Cunningsburgh (south Mainland) in about 1830 by the MP Samuel Laing. By the 1890's they had spread (thinly) over much of the south and east side of Mainland and a few were reported to have reached the west Mainland. Small numbers were also released at Reafirth and Windhouse on Yell in 1882 by J. Harrison but these apparently quickly disappeared from the island. The species appears to have survived reasonably well on Mainland during the early 1900's but they apparently caused 'considerable damage to the crops' and were widely and enthusiastically persecuted. Several were apparently still present in the Lunna area in 1935 although the last record of the species alive in Shetland is of two trapped in a turnip rig at Spiggie in 1937. There have been no records since that time.
Mountain Hare (Lepus timidus)
Mountain or 'Blue' Hares were introduced into Shetland by Mr. Anderton from Perthshire who introduced two pairs to Vaila (an island off the west Mainland) in about 1900. In addition, Dr. Munro brought individuals from Scotland to the Kergord estate in about 1907. The species is now widespread throughout Mainland and is apparently still surviving on Vaila.
Field or Hill Mouse (Apodemus sylvaticus)
Thought to have been introduced from Norway by Norse settlers although Venables & Venables (1955) considered this species to be a likely indigenous species to Shetland, indeed the only likely indigenous land mammal, and a possible subspecies of A.sylvaticus. It is ubiquitous throughout Shetland although is apparently absent from Out Skerries. Separate races have been described - for Yell and possibly Mainland (A.s.granti - Hinton 1914), Foula (A.s.thuleo - Hinton 1919) and Fair isle (A.s.fridariensis - Kinnear 1906).
House Mouse (Mus musculus)
Presumably introduced into Shetland by Norse settlers, this species is ubiquitous throughout Mainland and the inhabited islands.
Black or Ship Rat (Rattus rattus)
Introduced from ships with the earliest recorded occurrence either immediately prior to, or sometime between 1654 and 1680. The only documented localities were at Lerwick Harbour and and on Whalsay. The Whalsay colony was apparently discovered in 1904 and was known to have been still in existence in 1951.The species is almost certainly now extinct in Shetland and there have been no certain occurrences since at least 1990 although it has been known to be on some visiting vessels, e.g. klondykers.
Brown Rat (Rattus norvegicus)
This species was originally Introduced to Shetland from visiting vessels but its place of origin and date of introduction are unknown although Venables & Venables suggest that it may have been in about 1730. It has been reported on all the large inhabited islands except Yell (where it has been extinct within living memory) and Fetlar, although it appears to also be absent from most of the west Mainland.
Fox (Vulpes vulpes)
Apparently a single individual was introduced in Shetland the 1860s (locality unknown) but it was shot. From about 1990 onwards there have been rumours of sightings of a fox in the Sullom, Voe and Delting areas. On the 31st August 1996 a dog fox was found dead on the road at Olna between Voe and Brae, apparently shot at close range. However rumours of others have persisted in the same area. It appears a few animals have been brought in to Shetland and let loose deliberately or possibly even transported here as carcasses, possibly for some time. An 'Arctic type' individual was also found dead at Voe on the 14th February 1997. The animal was a fully-grown, adult male and was in very good condition, seemingly well-fed and with long claws, suggesting that it had not been fending for itself in the wild. There are no records of breeding.
Stoat (Mustela erminea)
Probably introduced in the late 1600s in the Dunrossness area (Venables & Venables). seventeenth century. Currently they are widespread throughout Mainland but apparently absent from the main isles (Yell, Unst, Fetlar, Whalsay), although they were introduced on Whalsay around 1900 to 'destroy rats and rabbits' but they subsequently became extinct.
Ferret-polecat (Mustela putorius x Mustela furo)
This widely kept hybrid was introduced to the isles through accidental or deliberate release in the 1980s. It has been the subject of an eradication programme since that time as the species causes considerable damage to ground nesting birds. Unfortunately it is now feral throughout Mainland although absent from all other islands.
Mink (Mustela vison)
Individuals were accidentally released from Mink farms in Shetland in the 1960s and 1970s. Although some of the individuals survived for a time there have been no recent sightings and they are now thought to be extinct.
Otter (Lutra lutra)
Although abundant in Shetland, the otter is one of the most threatened mammals in Europe where it has disappeared from large areas and become rarer in others. It was once thought to be indigenous to Shetland but is now presumed more likely to have been introduced, at least from Viking times, but actual origin and date of introduction are unknown.
About 14% of the total UK otter population is found in Shetland (approximately 900 - 1000 individuals) - it forms a very important part of the European total and is of national and international importance. As Shetland otters are isolated from those elsewhere in their range, they may also be a genetically distinct race - they are smaller and have more clearly marked white throat patches.
Otters are found in coastal areas throughout Shetland but one of the greatest concentrations occurs in the area around Yell Sound. They prefer low rocky coastlines with shallow water, feeding mainly around kelp beds on inshore fish such as eelpout, rockling and butterfish. Their holts (hadds) are usually dug out of soft peaty banks near the shore. Although Shetland otters spend many of their active hours in and around the sea, their coats are not designed for prolonged immersion in seawater. To keep their fur waterproof they must regularly bathe in fresh water burns, pools or lochs.