View source for North Ronaldsay sheep

{{short description|Breed of sheep from Scotland}}
{{Use dmy dates|date=April 2022}}
{{featured article}}
{{use British English|date=February 2017}}
{{Infobox sheep breed
| name          = North Ronaldsay sheep
| image         = North ron sheep.jpg
| image_size    =
| image_alt     =
| image_caption =Two sheep on the shoreline of North Ronaldsay
| status        = {{ubl|[[FAO]] (2007): Endangered<ref name=barb>Barbara Rischkowsky, Dafydd Pilling (editors) (2007). [https://web.archive.org/web/20200623201209/http://www.fao.org/3/a1250e/annexes/List%20of%20breeds%20documented%20in%20the%20Global%20Databank%20for%20Animal%20Genetic%20Resources/List_breeds.pdf List of breeds documented in the Global Databank for Animal Genetic Resources], page 138; annex to: [https://web.archive.org/web/20170110125634/http://www.fao.org/3/a-a1250e.pdf ''The State of the World's Animal Genetic Resources for Food and Agriculture'']. Rome: Commission on Genetic Resources for Food and Agriculture, Food and Agriculture Organization of the United Nations. {{isbn|9789251057629}}. Archived 23 June 2020.</ref> | [[Rare Breeds Survival Trust|RBST]] (2017): Category 3<ref name=rbst2>{{cite web|url=https://www.rbst.org.uk/Handlers/Download.ashx?IDMF=377bb88e-8e0b-4fbc-a47d-7abc65f4ccf5 |title=Watchlist 2017–18 |location=Stoneleigh Park, Warwickshire |publisher=Rare Breeds Survival Trust |access-date=30 April 2022}}</ref>}}
| altname       =
| nickname      =
| country       = [[Scotland]]
| distribution  =
| standard      =
| use           = meat, wool
| maleweight    ={{convert|30|kg|lb|round=5|abbr=on}}
| femaleweight  ={{convert|25|kg|lb|round=5|abbr=on}}
| maleheight    ={{convert|41|cm|in|abbr=on}}
| femaleheight  ={{convert|41|cm|in|abbr=on}}
| skincolour    =
| type          =
| woolcolour    = white, grey, brown, black
| facecolour    =
| horns         = horned
| note          =
}}

The '''North Ronaldsay''' or '''Orkney''' is a [[List of sheep breeds|breed]] of [[sheep]] from [[North Ronaldsay]], the northernmost island of [[Orkney]], off the north coast of [[Scotland]]. It belongs to the [[Northern European short-tailed sheep]] group of breeds, and has evolved without much [[cross-breeding]] with modern breeds. It is a smaller sheep than most, with the rams (males) horned and ewes (females) mostly [[polled livestock|hornless]]. It was formerly kept primarily for wool, but now the two largest flocks are [[feral]], one on North Ronaldsay and another on the Orkney island of [[Auskerry]]. The [[Rare Breeds Survival Trust]] lists the breed as a priority on its 2021–2022 watchlist, and they are in danger of [[rare breed|extinction]], with fewer than 600 registered breeding females in the United Kingdom.

The semi-feral flock on North Ronaldsay is the original flock that evolved to subsist almost entirely on [[seaweed]] – they are one of few mammals to do this. They are confined to the foreshore by a {{convert|1.8|m|ft|0|abbr=on}} early 19th century [[dry stone|drystane dyke]], which completely encircles the island, forcing the evolution of this unusual characteristic. The wall was built as [[kelping]] (the production of soda ash from seaweed) on the shore became uneconomical. Sheep were confined to the shore to protect the fields and [[Crofting|crofts]] inside, and afterwards they subsisted largely on seaweed.

This diet has caused a variety of adaptations in the sheep's digestive system. These sheep now extract the trace element copper far more efficiently than other breeds as their diet of seaweed has a limited supply of copper. This results in them being susceptible to [[copper toxicity]] if fed on a grass diet, as copper is toxic to sheep in high quantities. Grazing habits have also changed to suit the sheep's environment. They graze at low tide when the seaweed is exposed and then [[Ruminant|ruminate]] at high tide.

A range of [[Wool|fleece]] colours is exhibited, including grey, brown and red. Meat from the North Ronaldsay has a distinctive flavour, described as "intense" and "gamey",<ref name="Hollweg"/> possibly in part due to the high iodine content in their diet of seaweed.

== History ==
=== Origin ===
[[File:Sheep and seals, Nouster Bay, North Ronaldsay - geograph.org.uk - 710686.jpg|alt=A white sheep, pictured with two lambs on the seaweed covered beach, next to seals lying in the sand.|thumb|240x240px|A North Ronaldsay sheep with twin lambs on the beach, with seals in the background]]

The sheep are descended from the [[Northern European short-tailed sheep]]. Their arrival onto North Ronaldsay is not known precisely but it may have been as early as the [[Iron Age]],<ref>{{cite book|url=https://books.google.com/books?id=7YC3cYhGMOcC |title=Introduced Mammals of the World: Their History, Distribution and Influence |last=Long |first=John L. |publisher=CSIRO Publishing |year=2003 |isbn=9780643099166 |pages=527 |via=[[Google Books]]}}</ref> or possibly even earlier,<ref>{{cite journal|last1=Balasse |first1=Marie |last2=Tresset |first2=Anne |last3=Obein |first3=Gaël |last4=Fiorillo |first4=Denis |last5=Gandois |first5=Henri  |title=Seaweed-eating sheep and the adaptation of husbandry in Neolithic Orkney: new insights from Skara Brae |journal=[[Antiquity (journal)|Antiquity]] |year=2019 |volume=93  |issue=370 |pages=919–932 |doi=10.15184/aqy.2019.95|s2cid=202375768 |url=https://hal.archives-ouvertes.fr/hal-02304703/file/Balasse%20et%20al.%202019%20Antiquity-HAL.pdf }}</ref><ref>{{cite journal|last1=Blanz |first1=Magdalena |last2=Balasse |first2=Marie |last3=Card |first3=Nick |last4=Ascough |first4=Philippa |last5=Fiorillo |first5=Denis |last6=Taggart |first6=Mark |last7=Feldmann |first7=Jörg |last8=Mainland |first8=Ingrid |year=2022 |title=Life, Death and Teeth of Late Neolithic Sheep and Red Deer Excavated at Ness of Brodgar, Orkney Islands (UK) |journal=[[Environmental Archaeology]] |pages=1–13 |doi=10.1080/14614103.2022.2146320|s2cid=253602610 |doi-access=free }}</ref> which would make them potentially the earliest ovines to arrive in Britain. Because of their isolated location, they have evolved without much [[Crossbreed|admixture]] from imported Roman and European breeds.<ref name="porter">{{cite book|chapter-url=https://books.google.com/books?id=2UEJDAAAQBAJ |title=Mason's World Encyclopedia of Livestock Breeds and Breeding |last=Alderson |first=Lawrence |publisher=CAB International |editor-last1=Porter |editor-first1=Valerie |editor-last2=Alderson |editor-first2=Lawrence |editor-last3=Hall |editor-first3=Stephen J. G. |editor-last4=Spoonenberg |editor-first4=Phillip |year=2016 |isbn=9781845934668 |volume=2 |pages=872–74 |chapter=Sheep |via=[[Google Books]]}}</ref><ref name=":1">{{cite book|url=https://books.google.com/books?id=WJCTL_mC5w4C&q=ronaldsay |title=The Encyclopedia of Historic and Endangered Livestock and Poultry Breeds |last=Vorwald Dohner |first=Janet |publisher=[[Yale University Press]] |year=2001 |isbn=9780300138139 |pages=96–98 |via=[[Google Books]]}}</ref> They share some characteristics, including their colour range and short tails, with [[Scandinavia]]n sheep introduced when the islands were under [[Norsemen|Norse]] control, between the 9th and 15th centuries.<ref>{{cite journal|last=Ryder |first=M. L. |year=1981 |orig-year=1978 |title=A survey of European primitive breeds of sheep |journal=Annales de Génétique et de Sélection Animale |volume=13 |issue=4 |pages=381–418 |doi=10.1186/1297-9686-13-4-381 |pmc=2718014 |pmid=22896215 |doi-access=free }}</ref>

=== Enclosure ===
In 1832, a [[dry stone|drystane dyke]] was erected on the island. Its construction was part of the response to the collapse of the kelping industry, which was the production of [[soda ash]] by the burning of seaweed. To provide a livelihood for those previously employed in kelping, the inland farmlands were reorganized, and the sheep kept away from the fields or [[Crofting|crofts]].<ref name=OSF>{{cite web |title=The Dyke: Origin |url=http://www.theorkneysheepfoundation.org.uk/the-dyke-origin/ |publisher=[[Orkney Sheep Foundation]] |access-date=21 February 2018 |archive-date=21 February 2018 |archive-url=https://web.archive.org/web/20180221161409/http://www.theorkneysheepfoundation.org.uk/the-dyke-origin/ |url-status=dead }}</ref> Since then, the flocks on the island have been [[Feral animal|feral]].<ref>{{cite book|title=The Encyclopedia of Historic and Endangered Livestock and Poultry Breeds |last=Vorwald Dohner |first=Janet |publisher=[[Yale University Press]] |year=2001 |isbn=9780300138139 |pages=96–97 }}</ref><ref name="Native">{{cite web |url=http://www.sheep-isle.dk/Ronaldsay/native.htm |work=The Native Sheep of North Ronaldsay |title=A historic Introduction |publisher=Sheep-Isle |access-date=23 April 2009 |archive-date=9 March 2013 |archive-url=https://web.archive.org/web/20130309010725/http://www.sheep-isle.dk/Ronaldsay/native.htm |url-status=dead }}</ref><ref>{{cite web|url=http://www.dailyrecord.co.uk/news/scottish-news/scots-islanders-battle-stop-flock-6619224 |title=Dyke under threat |last=Duke |first=Charile |date=12 October 2015 |website=[[Daily Record (Scotland)|Daily Record]] |access-date=2 December 2016}}</ref><ref name=":5" /> The wall also unintentionally reduced the chances of crossbreeding, which would have diluted the [[gene pool]] of an already vulnerable breed.<ref>{{cite news|url=https://www.pressandjournal.co.uk/fp/news/islands/orkney/914682/seaweed-eating-sheep-get-their-own-special-festival/ |title=Seaweed Sheep get their own festival |date=11 May 2016 |work=Press and Journal |access-date=2 December 2016}}</ref> The wall circles the entire coast of the island, {{convert|19|km|mi|0|abbr=on}}, and is {{convert|1.8|m|ft|0}} high, making it one of the largest [[dry stone]] walls in the world. In 1999, [[Historic Scotland]] described it as a "unique and important structure" and designated it an 'A'-list site requiring conservation.<ref name="buildingsatrisk">{{cite web|url=http://www.buildingsatrisk.org.uk/details/910565 |title=North Ronaldsay Dyke Information |website=Buildings At Risk Scotland |access-date=2 December 2016}}</ref><ref name=":6">{{cite web|url=http://portal.historicenvironment.scot/designation/LB46400 |title=North Ronaldsay, Sheep Dyke and Associated Punds – Listing |website=[[Historic Scotland]] Portal |access-date=1 January 2017}}</ref> This status affords it special protection; any development has to be approved with conservation in mind.<ref>{{cite web|url=https://www.historicenvironment.scot/advice-and-support/listing-scheduling-and-designations/listed-buildings/what-is-listing/#listing-and-development_tab |title=What is listing? |website=[[Historic Scotland]] |access-date=1 January 2017}}</ref>

Since the wall was erected, the human population of North Ronaldsay has fallen from 500 to around 50, and current residents lack the manpower to maintain the wall.<ref>{{cite news|url=https://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-34504358 |title=Plans considered to preserve North Ronaldsay sheep dyke |date=12 October 2015 |access-date=10 January 2017 |newspaper=[[BBC News]]}}</ref> Successive storms, the most damaging of which was in December 2012, have created large holes in the structure. The cost of repairs has been estimated at several million pounds. In 1902, it cost only [[Pre-decimal British Coinage|4 pence]] per hour to repair the wall, using stone taken from the shore.<ref name=":8">{{cite book|chapter-url=https://books.google.com/books?id=4vEEAAAAMAAJ |title=Studies in Folk Life (RLE Folklore): Essays in Honour of Iorwerth C. Peate |last=Fenton |first=Alexander |publisher=[[Routledge]] |year=2015 |isbn=9781317549901 |editor-last=Jenkins |editor-first=G. |pages=208 |chapter=Sheep in North Ronaldsay |via=[[Google Books]]}}</ref> In 2015, Orkney Islands Council reported that some {{convert|4.7|km|mi|abbr=on|0}} of the wall was in need of work, and that the rate of damage exceeded that of repair.<ref name="buildingsatrisk" />

=== Punds ===
[[File:North Ronaldsay sheep pund - geograph.org.uk - 176506.jpg|alt=An area surrounded by dry stone walling with a gate at one end to keep sheep enclosed.|thumb|An example of a pund]]
The [[Animal pound|punds, or pound]]s, also listed with Historic Scotland,<ref name=":6" /> are nine small enclosures situated across the island to contain the sheep for [[Sheep shearing|shearing]], counting, [[Domestic sheep reproduction|lambing]] and slaughtering.<ref>{{cite book|last=Fenton |first=A. |chapter=Sheep in North Ronaldsay, Orkney |title=Studies in Folk Life |editor-last=Jenkins |date=1969 |pages=210 |location=London |publisher=[[Routledge]]}}</ref> The sheep are herded inside these punds twice a year, the only time they have access to grass feed. Between February and August, the sheep are brought into the punds, once for lambing and once for shearing.<ref name=":5" /> The lambs are born on the grass between February and May. At this time, the sheep are counted, lambs are given [[ear tag]]s, and records are entered with the island's sheep court to record ownership.<ref name=Vorwalk97>Vorwald Dohner, ''Encyclopedia'', p. 97.</ref><ref name=":10">{{cite book|url=https://books.google.com/books?id=M_JVZlgM0N8C |title=The Land That Thyme Forgot |last=Black |first=William |publisher=[[Random House]] |year=2006 |isbn=9780552152099 |pages=155 |via=[[Google Books]]}}</ref> Shearing takes place in July and August, and the whole island community is involved in herding and shearing the sheep.<ref name=":9">{{cite book |url=https://books.google.com/books?id=dSUqAzuwS2QC&q=north+ronaldsay+sheep+punds&pg=PA176 |title=The Fleece & Fiber Sourcebook: More Than 200 Fibers, from Animal to Spun Yarn |last1=Ekarius |first1=Carol |last2=Robson |first2=Deborah |publisher=Storey Publishing |year=2011 |isbn=9781603427647 |pages=176–177 |via=[[Google Books]]}}</ref> Slaughtering takes place only in winter when the meat is needed, and when the animals are fatter and yield more meat, since seaweed is more abundant in winter.<ref name=Vorwalk97/>

=== Sheep court ===
In 1839, just after the wall was erected, the North Ronaldsay Sheep Court was created. A group of eleven appointed islanders were responsible for the maintenance of the wall, the health of the sheep flock, and recording ownership of the sheep.<ref>Black, ''Land That Thyme Forgot'', p. 155.</ref><ref>{{cite book|url=https://books.google.com/books?id=hwSypkGEg4EC&q=north+ronaldsay+sheep+court&pg=PT364|title=Bird Observatories of the British Isles |last1=Archer |first1=Mark |last2=Grantham |first2=Mark |last3=Howlett |first3=Peter |last4=Stansfield |first4=Steven |publisher=[[Bloomsbury Publishing|Bloomsbury]] |year=2010 |isbn=9781408139066 |via=[[Google Books]]}}</ref> Today, the Sheep Court remains the regulatory body responsible for organising ownership of the sheep.

=== Conservation ===
The North Ronaldsay Sheep Fellowship is one of several organisations concerned with the survival of the breed. They maintain the [[Breed registry|flock book]], established in 1974, which is the breed registry containing all [[Purebred|purebred animals]].<ref name=":4" /> This book reports that there are fewer than 600 breeding females and roughly 3700 sheep in total.<ref>{{Cite web |last=Moody |first=Kevin |date= |title=North Ronaldsay Sheep Breed Fellowship |url=https://northronaldsaysheepfellowship.com/ |url-status=live |archive-url=https://web.archive.org/web/20161203123734/http://nrsf.moonfruit.com/breed-profile/4514127070 |archive-date=3 December 2016 |access-date=2 December 2016 |website=northronaldsaysheepfellowship.com |publisher=North Ronaldsay Sheep Fellowship}}</ref><ref name=":11" /> The [[Rare Breeds Survival Trust]] (RBST) lists the North Ronaldsay as "vulnerable".<ref name=":11">{{Cite news|url=http://www.rbst.org.uk/Our-Work/Resource-Library/RBST-Publications/The-Ark|title=Watchlist 2014|date=Spring 2014|work=The Ark|publisher=[[Rare Breeds Survival Trust]]|access-date=28 February 2017|archive-date=1 March 2017|archive-url=https://web.archive.org/web/20170301180510/http://www.rbst.org.uk/Our-Work/Resource-Library/RBST-Publications/The-Ark|url-status=dead}}</ref>

Other island-based organisations include The North Ronaldsay Trust and the Orkney Sheep Foundation, who run an annual Sheep Festival (SheepFest) inviting volunteers to the island for a fortnight of sheepdyke rebuilding.<ref>{{cite web |title=North Ronaldsay Sheep Festival |url=https://www.nrsheepfestival.com/ |access-date=26 April 2023}}</ref>

There are only two main populations of the breed. The primary one is on the island of North Ronaldsay itself; the other is on the island of Auskerry, which was established in 1983 by Teresa Probert and Simon Brogan.
Modern [[DNA]] [[DNA profiling|analysis]] has shown little crossbreeding with other sheep breeds from mainland Britain. Testing carried out under the National [[Scrapie]] Plan looked for the ARQ [[allele]], which protects against the scrapie disease and is present in modern [[Selective breeding|selectively bred]] sheep, and found it in only 1.3 per cent of North Ronaldsay sheep.<ref name="Alderson873" /><ref>{{Cite web|url=http://www.soayfarms.com/scrapie.html|title=The Case for Exempting Primitive Sheep from the National Scrapie Plan|last=Morris|first=June|date=September 2000|publisher=Soay Farms|access-date=4 January 2016}}</ref><ref>{{Cite journal|last1=Townsend|first1=S. J.|last2=Warner|first2=R.|last3=Dawson|first3=M.|year=2005|title=PrP genotypes of rare breeds of sheep in Great Britain|url=http://veterinaryrecord.bmj.com/content/156/5/131|journal=Veterinary Record|volume=156|issue=5|pages=131–34|doi=10.1136/vr.156.5.131|pmid=15715003|s2cid=43625862|access-date=1 March 2017|archive-date=6 November 2018|archive-url=https://web.archive.org/web/20181106142056/https://veterinaryrecord.bmj.com/content/156/5/131|url-status=dead|url-access=subscription}}</ref>

Further DNA studies comparing the bones of the North Ronaldsay with remains of North European short-tailed sheep found on a [[Skara Brae]] site dating from around 3000 BCE have shown a very close match, suggesting that the North Ronaldsay has not genetically mixed with other breeds.<ref name=":2" />

== Characteristics ==
=== Physical ===
North Ronaldsays are very small sheep, an adaptation to the harsh, cold environment. Rams typically weigh around {{convert|30|kg|lb|round=5|abbr=on}}, and ewes rarely exceed {{convert|25|kg|lb|abbr=on}}, both standing around {{convert|41|cm|in|abbr=on}} high at the [[withers]] (shoulders).<ref name=Alderson873>Alderson, "Sheep", p. 873.</ref> The sheep are slow-growing and a full-size carcass<!--is this a "dressed" ([[Dressed weight]]) carcass?--> may weigh only {{Convert|13.6|kg|lb|0}}.<ref name="hall">{{cite journal |last=Hall |first=Stephen J. G. |date=1975 |title=Some recent observations on Orkney Sheep |url=https://www.researchgate.net/publication/229820930 |journal=[[Mammal Review]] |volume=5 |issue=2 |pages=59–64 |doi=10.1111/j.1365-2907.1975.tb00187.x}}</ref>

The North Ronaldsay is a descendant of the primitive European short-tailed sheep breed. As the name of the descent parent would suggest, they have naturally short tails. Their bones are finer than other breeds and their head is dished (sloping inwards).<ref name=Alderson873/> Rams are all horned; these horns are typically ridged and spiraled.<ref name=":4">{{Cite web|url=http://dad.fao.org/|title=FAO Livestock Database|website=fao.org|publisher=[[United Nations Food and Agriculture Organization]]|access-date=3 December 2016}}</ref> Only 20 per cent of the ewes are horned; the rest are [[Polled livestock|polled]] (hornless).<ref name=Vorwalk97/>

=== Diet ===
North Ronaldsay sheep have a highly unusual diet consisting almost solely of seaweed. This has evolved due to their unique location, confined to the shoreline by a {{convert|1.8|m|ft|0|abbr=on}} dry stone wall, leaving only seaweed for food. Apart from the [[marine iguana]], native to the [[Galapagos Islands]], it is the only land animal known to have such a diet.<ref name=":5">{{cite web|url=https://www.bbc.co.uk/future |title=North Ronaldsay sheep eat seaweed and little else |last=Ruggeri |first=Amanda |date=24 September 2015 |website=bbc.co.uk |publisher=[[BBC]] |access-date=21 February 2018 |url-status=live |archive-url=https://web.archive.org/web/20170213201859/http://www.bbc.co.uk/earth/story/20150924-north-ronaldsay-sheep-eat-seaweed-and-little-else |archive-date=13 February 2017}}</ref><ref>{{cite web|url=http://www.arkive.org/galapagos-marine-iguana/amblyrhynchus-cristatus/ |title=Galapagos marine iguana videos, photos and facts – Amblyrhynchus cristatus |website=ARKive |access-date=31 December 2016 |archive-url=https://web.archive.org/web/20161124025939/http://www.arkive.org/galapagos-marine-iguana/amblyrhynchus-cristatus/ |archive-date=24 November 2016 |url-status=dead}}</ref> Studies have shown that, due to preference and availability, the sheep eat mainly [[kelp]]s (''[[Laminaria digitata]]'' and ''[[Laminaria hyperborea]]''). This discovery led to suggestions that these kelps may be of use as an alternative food source for other livestock.<ref>{{cite journal|last=Hansen |first=H. R. |year=2003 |title=A qualitative and quantitative evaluation of the seaweed diet of North Ronaldsay sheep |journal=Animal Feed Science and Technology |volume=105 |issue=1–4 |pages=21–28 |doi=10.1016/S0377-8401(03)00053-1}}</ref>

The grazing habits of the sheep have also adapted to their unusual diet: instead of [[Diurnality|grazing during the day]] and [[Ruminant|ruminating]] (digesting) at night as other sheep generally do, the North Ronaldsays graze as the [[tide]] uncovers the shore (twice in 24 hours), ruminating at high water.<ref>{{cite journal|last1=Smale |first1=Dan A. |last2=Burrows |first2=Michael T. |last3=Moore |first3=Pippa. |last4=O'Connor |first4=Nessa. |last5=Hawkins |first5=Stephen J. |year=2011 |title=Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective |journal=[[Ecology and Evolution]] |volume=3 |issue=11 |pages=4016–38 |doi=10.1002/ece3.774 |pmc=3810891 |pmid=24198956}}</ref> Feeding begins around 3.5 hours after high tide as the areas of kelp and seaweed are exposed. Four hours later, which is just after the low tide, feeding ends, allowing rumination to begin. This cycle reduces the chance of the sheep becoming stranded at sea by the incoming tide.<ref name="National Research Council p. 30">National Research Council, ''Managing Global Genetic Resources'', p. 30.</ref>

In spring, mother ewes are taken to grasslands without access to seaweed for lambing, and are only returned to the shore around August. The other sheep (males and non-pregnant females) remain on the shore, primarily consuming seaweed, throughout the year.<ref>{{cite journal|last1=Hansen |first1=H.R. |last2=Hector |first2=B.L. |last3=Feldmann |first3=J. |year=2003 |title=A qualitative and quantitative evaluation of the seaweed diet of North Ronaldsay sheep |journal=Animal Feed Science and Technology |volume=105 |issue=1–4 |pages=21–28 |doi=10.1016/S0377-8401(03)00053-1}}</ref> Unusually for sheep, the North Ronaldsay fattens in winter when storms throw larger amounts of kelp and seaweed onto the shore and food is abundant.<ref>{{cite web|url=http://www.fao.org/3/x8750e/x8750e02.pdf |title=Farm Animal Genetic Resources – Part 2 |website=fao.org |publisher=[[United Nations Food and Agriculture Organization]] |access-date=14 January 2016}}</ref>

The sheep's source of fresh water is limited to the few freshwater lochs and ponds along the seashore.<ref>Hall, "Some recent observations", p. 60.</ref> This has led them to become very [[Halotolerance|salt tolerant]], as their diet is salt-rich, and access to fresh water is limited. Compared with other breeds of sheep, they can far better handle elements present in the [[sea salt]].<ref>{{cite journal|last1=Mirkena |first1=T. |last2=Duguma |first2=G. |last3=Haile |first3=A. |last4=Tibbo |first4=M. |last5=Okeyo |first5=A.M.|last6=Wurzinger|first6=M. |last7=Sölkner |first7=J. |year=2010 |title=Genetics of adaptation in domestic farm animals: A review |journal=Livestock Science |volume=132 |issue=1–3 |pages=1–3 |doi=10.1016/j.livsci.2010.05.003}}</ref> These empirical conclusions were drawn in a 1997 study, but the underlying biological mechanism has yet to be understood.<ref name="National Research Council p. 30"/><ref>{{cite book|title=Genetic Resources and Conservation |last=Ponzoni |first=R. W. |publisher=CAB International |editor-last1=Piper |editor-first1=L.A. |editor-last2=Ruvinsky |editor-first2=A. |year=1997 |isbn=9780851992006 |pages=437–69 |chapter=The Genetics of Sheep}}</ref>[[File:NR sheep.jpg|alt=A large herd of North Ronaldsay on the beach, exhibiting many different coat colours: white, brown, grey and black.|thumbnail|A herd of North Ronaldsay sheep on the beach]]

==== Scientific analysis ====
The sheep have [[Natural selection|evolved]] a somewhat different [[physiology]] from other sheep, due to their unusual diet: their digestive system has adapted to extract the sugars in seaweeds more efficiently.<ref name=Vorwalk97/> A 2005 study at the [[University of Liverpool]] found that they have a greater susceptibility to [[copper toxicity]], when compared with a more traditional breed such as the [[Cambridge (sheep)|Cambridge]].<ref name="NIH">{{cite journal|first1=S. |first2=D. M. |first3=G. |first4=R. J. |year=2005|title=The greater susceptibility of North Ronaldsay sheep compared with Cambridge sheep to copper-induced oxidative stress, mitochondrial damage and hepatic stellate cell activation |journal=[[Journal of Comparative Pathology]] |volume=133 |issue=2–3 |pages=114–127 |doi=10.1016/j.jcpa.2005.02.001 |pmid=16099232 |last1=Haywood |last2=Simpson |last3=Ross |last4=Beynon}}</ref> This is because seaweed has a chemical which inhibits the absorption of copper, so the sheep have to absorb copper more efficiently to obtain the required amount.<ref name=Vorwalk97/> The levels of copper found in typical sheep feed, including grass, are toxic for this breed.<ref name=Alderson873/><ref>{{Cite journal|last1=Haywood|first1=S.|last2=Müller|first2=T.|last3=Müller|first3=W.|last4=Heinz-Erian|first4=P.|last5=Tanner|first5=M.S.|last6=Ross|first6=G.|year=2001|title=Copper-associated liver disease in North Ronaldsay sheep: a possible animal model for non-Wilsonian hepatic copper toxicosis of infancy and childhood|journal=The Journal of Pathology|volume=195|issue=2|pages=264–69|doi=10.1002/path.930|pmid=11592108|s2cid=21884564}} p. 265</ref> Studies at the Universities of Liverpool and [[University of Minnesota|Minnesota]] suggest that they can extract four times more copper from their diet than more traditional breeds.<ref name="NIH" /><ref>{{Cite book|title=The Chance to Survive: Rare Breeds in a Changing World|last=Alderson|first=Lawrence|publisher=Cameron & Tayleur|year=1978|isbn=9780715376324|pages=76–80}}</ref>

[[Stable isotope ratio]] analysis of bone [[collagen]] and [[tooth enamel]] from seaweed-eating North Ronaldsay sheep have revealed elevated stable carbon isotope ratios ([[Δ13C|δ<sup>13</sup>C]]) compared to sheep feeding on C<sub>3</sub>-vegetation.<ref>{{cite journal|last1=Balasse |first1=Marie |last2=Tresset |first2=Anne |last3=Dobney |first3=Keith |last4=Ambrose |first4=Stanley H. |year=2005 |title=The use of isotope ratios to test for seaweed eating in sheep |journal=[[Journal of Zoology]] |volume=266 |issue=3 |pages=283–91 |doi=10.1017/S0952836905006916}}</ref><ref>{{cite journal|last1=Blanz |first1=Magdalena |last2=Mainland |first2=Ingrid |last3=Richards |first3=Michael |last4=Balasse |first4=Marie |last5=Ascough |first5=Philippa |last6=Wolfhagen |first6=Jesse |last7=Taggart |first7=Mark |last8=Feldmann |first8=Jörg |year=2020 |title=Identifying seaweed consumption by sheep using isotope analysis of their bones and teeth: Modern reference δ¹³C and δ¹⁵N values and their archaeological implications |journal=[[Journal of Archaeological Science]] |volume=118  |pages=1–11 |doi=10.1016/j.jas.2020.105140 |s2cid=216206059 |url=http://eprints.gla.ac.uk/212826/13/212826.pdf }}</ref><ref>{{Cite journal |last1=Guiry |first1=Eric J. |last2=Szpak |first2=Paul |date=2020-09-15 |title=Seaweed‐eating sheep show that δ 34 S evidence for marine diets can be fully masked by sea spray effects |journal=Rapid Communications in Mass Spectrometry |language=en |volume=34 |issue=17 |doi=10.1002/rcm.8868 |issn=0951-4198|doi-access=free }}</ref> This difference in stable carbon isotope ratios (arising from dietary differences), discovered by studying North Ronaldsay sheep, is made use of in archaeological studies, which have shown the existence of seaweed-eating sheep on [[Orkney]] around 5000 years ago.<ref>{{cite journal|last1=Balasse |first1=Marie |last2=Tresset |first2=Anne |last3=Obein |first3=Gaël |last4=Fiorillo |first4=Denis |last5=Gandois |first5=Henri  |title=Seaweed-eating sheep and the adaptation of husbandry in Neolithic Orkney: new insights from Skara Brae |journal=[[Antiquity (journal)|Antiquity]] |year=2019 |volume=93  |issue=370 |pages=919–932 |doi=10.15184/aqy.2019.95|s2cid=202375768 |url=https://hal.archives-ouvertes.fr/hal-02304703/file/Balasse%20et%20al.%202019%20Antiquity-HAL.pdf }}</ref><ref>{{cite journal|last1=Blanz |first1=Magdalena |last2=Balasse |first2=Marie |last3=Card |first3=Nick |last4=Ascough |first4=Philippa |last5=Fiorillo |first5=Denis |last6=Taggart |first6=Mark |last7=Feldmann |first7=Jörg |last8=Mainland |first8=Ingrid |year=2022 |title=Life, Death and Teeth of Late Neolithic Sheep and Red Deer Excavated at Ness of Brodgar, Orkney Islands (UK) |journal=[[Environmental Archaeology]] |pages=1–13 |doi=10.1080/14614103.2022.2146320|s2cid=253602610 |doi-access=free }}</ref>

== Use ==
=== Meat ===
When the United Kingdom was in the [[European Union]], lamb and mutton from the sheep could be marketed as "Orkney Lamb", which had [[Protected Designation of Origin]] status.<ref>{{cite web|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/271263/pfn-orkney-lamb.pdf |title=Product Specification – "Orkney Lamb" |website=gov.uk |publisher=[[Department for Environment, Food and Rural Affairs|DEFRA]] |access-date=2 December 2016}}</ref> The meat has a unique, rich flavour, which has been described as "intense and almost [[Game (hunting)|gamey]]",<ref name="Hollweg" /> and has a darker colour than most mutton, due in part to the animals' [[iodine]]-rich diet.<ref name="Hollweg">{{cite news |url=http://www.thesundaytimes.co.uk/sto/style/food/article79597.ece |archive-url=https://web.archive.org/web/20170301180422/http://www.thesundaytimes.co.uk/sto/style/food/article79597.ece |url-status=dead |archive-date=1 March 2017 |title=The Virtues of North Ronaldsay Lamb |last=Hollweg |first=Lucas |date=3 February 2008 |work=[[The Sunday Times]] |access-date=4 March 2017}}</ref>

=== Wool ===
[[File:North Ronaldsay sheep behind fence.jpg|alt=Two black North Ronaldsay sheep shown behind a fence, with long horns curved behind them and chewing on a carrot.|thumb|An example of the face of North Ronaldsay sheep]]
Despite their slight size, North Ronaldsay sheep were historically raised for their wool. It comes in a variety of colours and is very similar to the [[Shetland]] breed, due to their common ancestor. More common typical colours are the whites and greys, but browns, beiges, reds (also called tanay) and blacks, with coarser hair, are all exhibited.<ref>Hall, "Some recent observations", p. 59.</ref><ref>{{Cite book|url=https://books.google.com/books?id=Kd4ODQAAQBAJ&q=ronaldsay&pg=PT74|title=Guide To The Primitive Breeds Of Sheep And Their Crosses On Exhibition At The Royal Agricultural Society's Show, Bristol 1913|last=Elewes|first=Henry|publisher=Read Books|year=2016|isbn=9781473352018|via=[[Google Books]]}}</ref> A full fleece weighs about {{convert|1|kg|lb|0|abbr=on}}.<ref name=Alderson873/><ref>Ekarius and Robson, ''Fleece & Fiber Sourcebook'', p. 176.</ref><ref>{{Cite book|url=https://books.google.com/books?id=Ie1SqUIjtZIC&q=north+ronaldsay+sheep&pg=PA146|title=The Field Guide to Fleece: 100 Sheep Breeds & How to Use Their Fibers|last1=Ekarius|first1=Carol|last2=Robson|first2=Deborah|date=2013|publisher=Storey Publishing|isbn=978-1603429269|page=147|via=[[Google Books]]}}.</ref>

The North Ronaldsay is a double-coated breed, meaning they have a wool undercoat and overcoat.<ref name=":2">{{cite book|url=https://books.google.com/books?id=CPs-BAAAQBAJ&q=north+ronaldsay+sheep&pg=PT201 |title=Pure Wool: A Guide to Using Single-Breed Yarns |last=Blacker |first=Susan |publisher=Stackpole Books |year=2012 |isbn=9780811760959 |via=[[Google Books]]}}</ref> The undercoat tends to be finer and soft, suitable for garments that would touch the skin, whereas the overcoat is coarser, with long hair that protects the sheep from the cold, wet weather of their natural environment. This fibre is more durable and tends to be used in overgarments.<ref>Ekarius and Robson, ''Field Guide to Fleece'', pp. 146–47.</ref>

== See also ==
* [[List of domesticated Scottish breeds]]

== References ==
{{commonscat}}
{{reflist}}

{{British livestock|R.1}}
{{Scottish animal breeds}}

{{DEFAULTSORT:North Ronaldsay (Sheep)}}
[[Category:Biota of Orkney]]
[[Category:Sheep breeds]]
[[Category:Sheep breeds originating in Scotland]]
[[Category:Animal breeds on the RBST Watchlist]]
[[Category:British products with protected designation of origin]]
[[Category:North Ronaldsay]]