Compared to much of the rest of Europe, Britain doesn't have a great variety of fauna. Cut off from the rest of the continent since the Ice Ages, there wasn't a great diversity of mammal life anyway, and with the arrival of the Normans from France in 1066 came hunting as a sport. Many species clinging on in the islands were driven to extinction in the Middle Ages.
Others have arrived, such as the grey squirrel and the mink (both from the USA), having a profound effect on the native wildlife. Although they are not considered 'British' by either most naturalists or the general public, they are worthy of discussion here as they are part of the wild landscape. We shall concentrate on 'wild' species; domesticated animals such as cows, dogs and horses have been introduced by humans and do not have wild populations in the UK. The following terms are used throughout this series of Entries:
Native: A species that is believed to have been resident in the UK when people first arrived on British soil.
Non-native/introduced: A species that is believed to have arrived as a result of man's influence; for farming or as a stowaway, for example. Note that escapees from zoos or private collections are also considered to belong to this category, as they would not have been in Britain were it not for man.
Re-introduced: A species that was once native, but became extinct and was brought back to Britain by man.
There are also mammals which would appear to some to be wild, such as moorland ponies, but domesticated animals are usually owned by someone and are considered to be semi-wild. Those domesticated mammals that have escaped or been released and now live truly free are referred to as 'feral' animals.
Though this series of Entries mentions Ireland in passing, it does not specifically consider Irish mammals. The term 'UK' refers to the United Kingdom of Great Britain and Northern Ireland, as although mammals don't generally respect the borders between countries, the wildlife researchers and conservation workers that study them certainly do.
What is a Mammal, Anyway?
All life on earth is classified by a system devised by Swedish botanist Carolus Linnaeus1, which divides everything alive into groups depending upon their physical characteristics – for example, those with a backbone are divided from those without. This is known as taxonomy, and is a very complicated subject requiring years of hard study! Mammals are a class of animals that make up a very small proportion of life on Earth. It is enough for the purposes of this Entry to explain this in rather simple terms:
Kingdom: Animalia. This defines animals as multi-celled organisms that reproduce through an embryo, which is itself created by the fertilisation of an egg by a sperm.
Phylum: Chordata. These are a subdivision of animalia that have a stiffened rod called a notochord between the gut and nerve chord when embryonic. If this all sounds a little technical, bear with it; this is still a very broad classification, but we're nearly there!
Class: Mammalia. Mammals are another subdivision that are warm-blooded, and with mammary glands in the females.
So all mammals share certain characteristics; they all have backbones, are warm-blooded, give birth to live young as a result of a sperm-fertilised egg and produce milk to wean their young on (hence the mammary glands).
Mammals are subdivided further into orders, which is a convenient way for us to arrange the entries in this series. We shall look at each of the eleven orders that occur in Britain in turn, in alphabetical order.
These are hoofed mammals that have an even number of functional toes on each foot. In Britain, these are:
- Domesticated cows, sheep, pigs and goats.
- Red deer Cervus elaphus, a truly native species in Scotland.
- Sika deer Cervus nippon, introduced to the UK around 1860, and are now considered naturalised.
- Fallow deer Dama dama, introduced by the Normans in the 11th Century.
- Roe deer Capreolus capreolus, hunted to extinction in the 18th Century, but re-introduced in the 19th.
- Reeves' Muntjac deer, Muntiacus reevesi, an escapee from Lord Rothschild's Bedfordshire park in the early 20th Century.
- Chinese water deer, Hydropotes inermis inermis, which was introduced to parks near the end of the 19th Century and now exists in the wild.
There are also herds of many other species of deer in parks around the country, and it is not inconcievable that one day escapees from these herds may form wild populations in the future.
Reindeer Rangifer tarandus were once native to Scotland, but were hunted to extinction around the 12th Century. A herd has been re-introduced to a farm in the Cairngorm region, but none are believed to live in the wild. Wild boar Sus scrofa are another native species, and are close to being considered an official part of Britain's wild fauna once again.
Carnivores in the UK belong to one of three families. The familiar common fox Vulpes vulpes belongs to the dog family and the Scottish wildcat Felis silvestris to the cat family. All the other terrestrial British carnivores belong to the Mustelidae family, which is the largest grouping of carnivores in the world.
- Eurasian badger Meles meles; recognisable to every schoolchild thanks to its black-and-white striped snout.
- European otter Lutra lutra, which is staging a recovery in the UK after years of decline.
- European pine marten Martes martes.
- European polecat Mustela putorius, from which ferrets are evolved.
- Least weasel Mustela nivalis.
- Stoat (also known as short-tailed weasel or ermine) Mustela erminea.
- American mink Mustela vison - interestingly, the Eurasian mink M. lutreola does not occur in Britain.
The two British seals belong to the Phocidae family, earless seals.
- Common seal Phoca vitulina; the most widespread of all pinnipeds with a global population of around half a million.
- Grey seal Halichoerus grypus; which occurs on both sides of the Atlantic and is estimated to have a global population of around 300,000.
It is very difficult to define cetaceans as native and non-native, as there are many species that pass through or inhabit the deeper waters off the UK. For the purposes of this series, species that can be seen from the shore will be considered native. Included in this group are one baleen whale and seven toothed whales:
- Minke Whale Balaenoptera acutorostrata
- Harbour porpoise Phocoena phocoena
- Common bottlenose dolphin Tursiops truncates
- Risso's dolphin Grampus griseus
- Short-beaked common dolphin Delphinus delphis
- White-beaked dolphin Lagenorhynchus albirostris
- Atlantic white-sided dolphin Lagenorhynchus acutus
- Killer whale Orcinus orca
All British bats belong to the suborder Microchiroptera, which means they use echolocation to find their prey. They are subdivided into two families; the Horseshoe bats, in the family Rhinolophidae, and the Vesper or evening bats, Vespertilionidae. With two horseshoes and fourteen vespers, there are more species of chiroptera than any other order in the UK.
- Common pipistrelle Pipistrellus pipistrellus
- Midge pipistrelle Pipistrellus pygmaeus
- Nathusius' pipistrelle Pipistrellus nathusii
- Common (or brown) long-eared bat Plecotus auritus
- Grey long-eared bat Plecotus austriacus
- Greater horseshoe bat Rhinolophus ferrumequinum
- Lesser horseshoe bat Rhinolophus hipposideros
- Daubenton's bat Myotis daubentonii
- Whiskered bat Myotis mystacinus
- Brandt's bat Myotis brandtii
- Natterer's bat Myotis nattereri
- Noctule Nyctalus noctula
- Leisler's bat Nyctalus leisleri
- Bechstein's bat Myotis bechsteinii
- Serotine Eptesicus serotinus
- Barbastelle Barbastella barbastellus
There are six wild insectivores in Britain in three families, the Erinaceidae (hedgehogs), the Talpidae (moles) and the shrew family, Soricidae.
- European hedgehog Erinaceus europaeus
- European mole Talpa europaea
- Common shrew Sorex araneus
- Pygmy shrew Sorex minutus
- Water shrew Neomys fodiens
- Lesser white-toothed or Scilly shrew Crocidura suaveolens cassiteridum
Three species of rabbits and hares are found in the UK:
- Rabbit Oryctolagus cuniculus
- Brown or common hare Lepus capensis
- Mountain or blue hare Lepus timidus
The red-necked wallaby Macropus rufogriseus is found in the Peak District, an escapee that has established itself in the wild. It is, however, clearly a recent introduction and cannot be treated as part of Britain's wild fauna. Yet.
These are again hooved mammals, this time with an odd number of toes. In Britain, the only species (non-native) is the domesticated horse Equus caballus, which belongs to the family Equidae (horse-like mammals). Zebras and donkeys are also member of this family.
As there are no truly wild species of perissodactyla in the UK, they will not feature in this series of Entries.
Unfortunately for the rest of the mammal population, a non-native primate made it to the UK, out-competing much of the local fauna and becoming the most populous and widespread mammal in the islands. A member of the Hominoidea family, Homo sapiens, commonly known as the human being, has become the dominant mammal.
Largely defined as such by their teeth, rodents comprise about half of the world's mammals.
- House mouse Mus musculus
- Wood mouse Apodemus sylvaticus
- Yellow-necked mouse Apodemus flavicollis
- Harvest mouse Micromys minutes
- Black rat Rattus rattus
- Brown rat Rattus norvegicus
- Water vole Arvicola terrestris
- Field vole Microtus agrestis
- Bank vole Clethrionomys glareolus
- Orkney vole Microtus arvalis orcadensis
- Hazel dormouse Muscardinus avellanarius
- Edible dormouse Glis glis, another of Lord Rothschild's collection to have established itself in the countryside.
- Red squirrel Sciurus vulgaris.
- Grey squirrel Sciurus carolinensis.