Animals of Ireland: Native Wildlife and Why There Are No Snakes

Why are there no snakes in Ireland?

Legend says that St Patrick, the 5th-century missionary, drove all the snakes of Ireland into the sea. The real explanation is geography and climate. During the last Ice Age, ice sheets and frozen tundra covered Ireland, and no reptiles could survive there. As the ice melted, animals slowly spread north again from warmer parts of Europe.

Rising sea levels cut Ireland off from Britain soon after the ice retreated, probably more than 10,000 years ago. Britain stayed joined to mainland Europe for longer, until roughly 8,000 years ago, so it received three native snakes: the adder, grass snake and smooth snake (see our guide to snakes in the UK). Cold-blooded reptiles spread slowly in a cool climate, and none of the snakes reached Ireland before the sea closed the route. The fossil record shows no evidence of snakes on the island at any time.

The same isolation explains why Ireland has fewer land mammals, amphibians and reptiles than Britain. Only about two dozen land mammal species, including bats, are thought to be native.

Ireland’s wildlife at a glance

Irish hare

The Irish hare (Lepus timidus hibernicus) is a subspecies of the mountain hare that lives only on the island of Ireland, and it has been on the island since the Ice Age. Unlike mountain hares in Scotland, which live mostly on high moorland and turn white in winter, Irish hares live everywhere from coastal dunes and farmland to bogs and mountains. Most stay brown or gray-brown all year, although some develop white patches in winter.

Irish hares are often seen on airfields, golf courses and grassland near the coast, and North Bull Island in Dublin Bay is a reliable place to watch them. In spring, females fend off over-eager males by “boxing” them, standing up on their hind legs. In parts of Northern Ireland, the introduced European brown hare now competes with the native hare.

Red deer: Killarney’s ancient herd

The red deer is Ireland’s largest wild land mammal. The herd in Killarney National Park, County Kerry, is the only one in Ireland that has lived wild on the island continuously for thousands of years, and it is protected by law. Other red deer herds, such as those in Glenveagh National Park in Donegal and the Wicklow Mountains, come from later introductions.

The best time to see them is the autumn rut in late September and October, when stags roar and clash antlers on the open slopes and lake shores around Killarney. Watch from paths and give rutting stags plenty of room. Our red deer profile explains their life cycle.

Sika deer from Japan, released at Powerscourt in County Wicklow in 1860, have spread widely and can interbreed with red deer, which is why the purity of the Killarney herd is carefully guarded.

Pine marten and red squirrel

The pine marten (Martes martes) is a slim, chocolate-brown relative of the weasel with a creamy yellow throat patch and a bushy tail. It was once rare in Ireland, but legal protection has allowed it to spread back across much of the country, especially in the west, midlands and south. It climbs well and eats small mammals, birds, eggs, insects and berries.

The red squirrel is native to Ireland. Gray squirrels from North America were released at Castle Forbes in County Longford in 1911 and spread across much of the east and midlands, replacing reds in many woods. Where pine martens have returned, gray squirrel numbers have fallen sharply and red squirrels have recovered. Grays spend more time on the ground and seem much less able to avoid the marten. See our red squirrel profile.

Badger and otter

The European badger is common across rural Ireland, living in family groups in large burrow systems called setts, usually in hedgerows, banks and woodland edges. It is mainly nocturnal and feeds on earthworms, insects, roots and fruit. Badgers are protected under Irish wildlife law, and old setts can be used by many generations.

Ireland is one of the strongholds of the Eurasian otter in western Europe. Otters live on rivers, lakes and canals across the country, and on the rocky Atlantic coast, where they often hunt in shallow sea water during the day. The best signs are tracks and droppings, called spraints, on rocks by the water. Read more in our Eurasian otter profile.

Irish stoat

The Irish stoat (Mustela erminea hibernica) is a subspecies found only in Ireland and the Isle of Man. Ireland has no weasels, so people often call the stoat a “weasel” anyway. It has a long, slim body, a chestnut-brown back and a cream belly. Unlike stoats in colder regions, Irish stoats rarely turn white in winter, and the dividing line between the dark back and pale belly is often wavy rather than straight.

Stoats hunt rabbits, rats, mice and birds along stone walls, hedgerows and riverbanks, and are often seen bounding across a road or popping up from a wall to look around. Our stoat profile covers the species as a whole.

Amphibians: natterjack toad, frog and newt

Only three amphibians live in Ireland. The natterjack toad (Epidalea calamita) is Ireland’s only toad. It is found in a handful of coastal sites in County Kerry, where it breeds in shallow, warm pools near sand dunes and saltmarsh, and it has also been introduced to a dune site in County Wexford. It has a thin yellow stripe down its back and runs rather than hops. Males give a loud, rattling chorus on spring nights. The species is considered endangered in Ireland, and conservation projects have created new breeding ponds and released young toads.

The common frog is widespread in ponds, ditches and bogs. Some historical accounts claim that it was introduced by people a few centuries ago, but whether it is native is still debated. The smooth newt is Ireland’s only newt, found mostly in ponds and drains in lowland areas.

The common lizard: Ireland’s only native land reptile

The common lizard (Zootoca vivipara), also called the viviparous lizard, is the only reptile native to dry land in Ireland. It is small, with a body length of about 5–8 cm (2–3 in) plus a longer tail, and brown with darker stripes and spots. It lives on bogs, heaths, sand dunes, coastal grassland and old stone walls, basking in the sun on warm days.

Its name refers to an unusual habit: in most of its range, including Ireland, females give birth to live young instead of laying eggs. The eggs develop inside the mother, which keeps them warm in a cool climate. This adaptation lets the species live farther north than any other land reptile.

The slow worm, a legless lizard often mistaken for a snake, lives in the Burren in County Clare, but it is not native. It was probably introduced in the 1970s. Leatherback turtles visit Irish waters in summer to feed on jellyfish, but they are ocean wanderers, not land residents.

Introduced and newly arrived animals

Many familiar Irish animals arrived with people. The European rabbit was brought by the Normans, and fallow deer were introduced in medieval times. More recent arrivals include the gray squirrel, sika deer and American mink, which escaped from fur farms and now hunts along rivers and coasts.

Two small mammals show how quickly Ireland’s wildlife is still changing. The bank vole was first recorded in southwest Ireland in the 1960s and has spread across much of the south. The greater white-toothed shrew was first detected in the late 2000s and is spreading fast, replacing the native pygmy shrew in places where it arrives.

Where to see wildlife in Ireland

• Killarney National Park, County Kerry: native red deer, sika deer, pine martens, otters and reintroduced white-tailed eagles on the lakes.
• The Burren, County Clare: common lizards, slow worms, pine martens and spectacular limestone wildflowers in May and June.
• North Bull Island, Dublin: Irish hares on the dunes, plus thousands of wintering ducks, geese and wading birds.
• Glenveagh National Park, County Donegal: red deer, and golden eagles from a reintroduction project that began in 2001.
• The Atlantic coast: gray and harbor seals, otters, and dolphins in the Shannon Estuary, home to a resident group of bottlenose dolphins.
• Castlemaine Harbour and the Dingle Peninsula, County Kerry: listen for natterjack toads calling on warm spring evenings.

Dawn and dusk are the best times for mammals. Keep to paths, use binoculars and never disturb setts, dens or breeding pools.