[1] The herd has remained remarkably genetically isolated for hundreds of years, surviving despite inbreeding depression due to the small population.

[2] There is also a small reserve herd of about 20 animals located on Crown Estate land near Fochabers, North East Scotland.

[4] To many visitors, the most striking element of the historic habitat at Chillingham is the widespread occurrence of large oak trees amongst grassland (wood pasture), providing a glimpse of Britain as many think it appeared in medieval times.

[6] A diversity of plants and animals find a habitat here, due to the absence of the intensive farming found in most other places in Britain.

[7] There are approximately 55 bird species, including common buzzards, European green woodpeckers, and the Eurasian nuthatch which claims this latitude as its northernmost range in the United Kingdom.

[11] However, the traditional view that these cattle have an unbroken line of descent, without intervening domestication, from the wild-living aurochs was already being called into question in the 1800s.

[12] Simon Schama described the famous contemporary woodcut by Thomas Bewick as "an image of massive power ... the great, perhaps the greatest icon of British natural history, and one loaded with moral, national and historical sentiment as well as purely zoological fascination".

Before the 13th century, this breed is claimed to have "roamed the great forest which extended from the North Sea coast to the Clyde estuary" according to the Countess of Tankerville.

During the 13th century, the King of England licensed Chillingham Castle to become "castellated and crenellated" and a drystone wall may well have been built then to enclose the herd.

In Victorian times, the idea that Chillingham cattle had connection with Roman imports was quite widely held but modern genetic studies[15] support earlier archaeological work [17] in rebutting this proposal.

The first genetic work was conducted from the early 1960s when, in connection with the development of blood typing techniques for cattle parentage testing, Dr J.G.

[25] Studies during winter hay feeding[26] showed that at this time when the cattle were forced into close proximity, cows had a complex social structure apparently based on individual pairwise relationships, while bulls had a linear hierarchy or "peck order".

The cattle are extremely vocal[27] with characteristic calls which echo around the area, especially when the bulls are excited by the discovery that a cow is coming into season.

[16] It is suggested that by a stochastic process of continual mild inbreeding, lethal recessives have been removed from the herd by genetic purging.

The Chillingham situation appears analogous; in other studies the persistence of runs of SNP heterozygosity has been taken to imply balancing selection at some loci.

[30] In 1939, the Chillingham Wild Cattle Association Limited was formed to study and protect these special creatures; in 1963 it became a registered charity.

A detailed review of the situation was conducted in 1887 by the British Association for the Advancement of Science,[35] but the best known general account is still Whitehead's The Ancient White Cattle of Britain and their Descendants.