Mammals

It’s easy to assume that they are big enough to look after themselves, but some of the UK’s mammal population face an uncertain future.

Mammals, issued on 13 April in a se-tenant block of ten 1st Class stamps, is the fourth instalment of Royal Mail’s Action for Species series, which highlights the plight of indigenous flora and fauna struggling for survival in a changing world.

The British Isles is home to more than 60 species of mammals, but almost half of these have been introduced from elsewhere in the world – and they include some of the most abundant, like the rabbit and grey squirrel.

All ten mammals are the subject of conservation programmes due to the effect of adverse changes in their environment caused by pollution, the growth in roads and housing developments, and in some cases the introduction of non-native species, which have all contributed to a fall in numbers.

Fortunately, thanks to the efforts of conservation groups and the public, we have become increasingly aware of the threats to our mammal populations, and many now benefit from legal protection and active conservation measures, and are showing encouraging signs of recovery.

The Action for Species series began with Birds in 2007 and continued with Insects in 2008 and Plants in 2009. 2010 is also the International Year of Biodiversity.

Prominent naturalists and representatives of conservation groups were asked to nominate UK mammal species that fitted the issue criteria. As the UK has comparatively few land mammals, the selection criteria was extended to marine mammals that spend at least part of their life cycle in UK territorial waters.

Once the nominations were received a short list was drawn up and Jason Godfrey was commissioned to find suitable photographic images for the set of ten stamps. While most of the images are from photo libraries the polecat and hedgehog were specially photographed for this issue.

Humpback Whale – Megaptera novaeangliae

Average weight: 45 tonnes, total length: 13–15m

This big, black whale with white under its tail has knobbly flippers that are longer than those of any other whale. Seen mainly in summer to the west of Britain, it arches its back to dive and feeds by sieving small fish from the water using a complex array of frilly plates found in its upper jaw instead of teeth.

Wildcat – Felis silvestris

Average weight: 5.5–6.5kg, total length: 75–110cm

Shy and nocturnal, and now confined to the wilder parts of Scotland, the wildcat resembles a tabby cat with prominent black stripes on the body and legs. Its tail is thick and round-ended compared to the domestic cat’s thin, pointed tail, but there are many hybrids. Female wildcats can produce one family a year, in spring.

Brown Long-eared Bat – Plecotus auritus

Average weight: 6–10g, total wingspan: 26–29cm

A small fluttery bat with enormous ears, this mammal is found throughout mainland Britain, except for the extreme north of Scotland. It commonly occurs in attics, as well as hollow trees and bird boxes, and often hovers to pick insects and spiders off trees. Completely harmless and a gentle creature, this is the bat most often found flying inside houses.

Sperm Whale – Physeter macrocephalus

Average weight: 15–40 tonnes, total length: 10–15m

The sperm whale, with its huge, blunt-ended head, is normally found in deep waters to the west of Britain, but occasionally strays into estuaries and gets stranded when the tide goes out. Usually solitary, the sperm whale sometimes lives in small groups. After swimming at the surface for about 10 minutes, it then dives deep for half an hour to feed, mainly on squid.

Water Vole – Arvicola terrestris

Average weight: 180–230g, total length: 29–31cm

A rat-sized animal with a chubby face and dark chocolate-brown fur, the water vole is a good swimmer and lives beside ponds, rivers and ditches, where it digs burrows in the banks and feeds on juicy vegetation, roots and bark. It is found mainly in the lowlands, throughout mainland Britain, usually in small colonies.

Greater Horseshoe Bat – Rhinolophus ferrumequinum

Average weight: 15–30g, total wingspan: 33–39cm

Large and broad-winged, this species of bat has a distinctive cone-shaped nose-leaf through which its echolocation sounds are focused. Its wings and ears are pale brown, and the fur is grey or buff, with a reddish tinge in older animals. Found mainly in south-west England and south Wales, it hibernates in caves, cellars and mines from October to May, wrapping its wings around its body while roosting. Its food consists of beetles and other large-bodied insects, caught in flight or snatched from the ground. In summer, females seek out warm places such as barn roofs, where, after a 75-day gestation period, they give birth to a single baby each year, nearly a third of its mother’s weight.

Otter – Lutra lutra

Average weight: 6–8kg, total length: 100–110cm

Large, long and sleek with short legs and webbed feet, the otter is normally seen only in or beside water, where it swims and dives frequently in pursuit of fish, crabs and other aquatic food. More widespread and numerous in western counties, many live along the shores of Scotland’s sea lochs. Otters will usually live alone or in a family group of a female and one to three young.

Dormouse – Muscardinus avellanarius

Average weight: 10–30g, average body length: 12–15cm

This golden-yellow mammal is the only British mouse with a thick fluffy tail. Found mostly in southern England, it is usually nocturnal and hibernates over the winter. Active among the branches of shrubs and trees, it feeds on flowers, fruits and insects.

Hedgehog – Erinaceus europaeus

Average weight: 500–1200g, total length: 20–25cm

Britain’s only spiny mammal is found throughout the UK. Normally nocturnal, it snuffles about in gardens, farmland and woodland, feeding on worms, beetles and other small prey. It rolls into a tight ball when alarmed, and hibernates for five to six months over winter.

Presentation Pack No. 440

The fully illustrated presentation pack contains all ten Mammals Stamps. Inside naturalist Pat Morris takes a look at each of the animals featured and some of the projects being undertaken to protect them. The pack was designed by The Partners and printed by Walsall Security Printers.

Stamp Cards

Ten postcards bearing enlarged images of each of the Mammals stamps go on sale about a week before the stamp issue date.

Feature	Type/Detail
Number of stamps	Ten
Design	Jason Godfrey
Photography	humpback whale © Brandon Cole/Nature Picture Library; wildcat © Peter Cairns/Nature Picture Library; brown long-eared bat © Les Stocker/Photolibrary Group Ltd; polecat © Paul Hobson/Royal Mail; sperm whale © Thomas Haider/Photolibrary Group Ltd; water vole © Terry Whittaker; greater horseshoe bat © Biosphoto/Frank & Philippe/Still Pictures; otter © Paul Hobson; dormouse © Stephen Dalton/NHPA/Photoshot; hedgehog © Laurie Campbell/Royal Mail
Stamp format	Square
Stamp size	35mm x 35mm
Printer	Cartor Security Printing
Print process	Lithography
Number per sheet	30/60
Perforations	14.5 x 14.5
Phosphor	Background screen
Gum	PVA

Text © reproduced with the permission of Royal Mail Group Ltd. All rights reserved.