Irish Fauna

Discover examples of Ireland's insects, mammals, birds, sea life & predators.


The animals found in Ireland today inhabit a landscape that was scoured by ice on a number of occasions over the last 100,000 years. At the later stages of this Ice Age, animals such as the giant deer Megaloceros giganteus lived in an Ireland with a climate similar to ours. They shared their landscape with woolly mammoths, spotted hyenas and brown bears.

Ireland has few mammal species, compared with other European countries. Only certain species travelled into Ireland before the island was separated from Britain and northwest Europe at the end of the Ice Age. Since then, many species have been introduced by humans. For example, the rabbit, which was introduced by Anglo-Normans in the 12th Century.

Irish Mammals

One of a series of very popular exhibits was made by the Dublin taxidermy firm of Williams & Son. They produced ‘family groups’ of badgers, otters and pine martens. These mammals are characteristic of the Irish landscape. Badgers are active at night, seeking out pastureland where they feed on earthworms, as well as many other ingredients in a highly varied diet. This brings them into contact with livestock. They share a disease with cattle, which is known as bovine tuberculosis. Although, the link between infection in badgers and cattle has not been confirmed, even after many decades of research. However, the suspected role of badgers in the infection of livestock has put them under pressure, with many thousands killed in programmes aimed at controlling the disease.

Bird Life

Many species of Irish birds featured in the exhibition. Bitterns have a distinctive booming call, which may be heard over long distances in wetlands. As reed beds were reduced owing to the drainage of many Irish wetlands over recent centuries, the bittern has ceased to breed here. Nowadays it is the turn of the Corncrake Crex to be threatened by changing farming practices. These birds are the subject of a campaign that may see corncrakes survive as a breeding bird in Ireland.

Francis Ledwidge (1887 – 1917) wrote a lament for his friend Thomas MacDonagh, who was executed in Dublin in 1916 for his part in the Easter Rising. It opens with the famous lines:

He shall not hear the bittern cry

In the wild sky where he is lain

Nor voices of the sweeter birds

Above the wailing of the rain


Predators that compete with farmers have always been under threat. Brown bears and wolves have been cleared from Ireland over the centuries, but golden eagles were common until the late 19th Century. By the late 20th Century, a programme to reintroduce golden eagles was under way in County Donegal.

Many mammals are most active at night and thus are a tempting food source for predators adapted to the dark. Large eyes and sensitive ears give owls a head start in catching prey. The short-eared owl is one of many birds that live in Ireland for part of the year. Voles are its favourite food in other countries, but these are not native to Ireland. Bank voles were introduced to the Cork/Kerry region in the mid 20th Century, and short-eared owls are now found in high densities in this area.

Female peregrine falcons are heavier than males. They use their weight to build up speed, dropping from a great height to crash into their prey with talons at the ready. Like many birds of prey, peregrine falcons have seen a dramatic reduction in their numbers during the 20th Century, but are now making a comeback.

Sea Life

Sea horses are now under pressure through the demand for delicacies in the restaurants of Asia. These small fish not only appear bizarre but also have unusual mating habits. It is the males that raise the young, sheltering a mass of eggs in a brood pouch until they hatch. The specimen on display was collected during the course of ongoing fieldwork and research by Museum staff.

Once common in some Irish rivers, the freshwater pearl mussel has been under pressure for many years because of the pearls that are occasionally enclosed in its shell. Just like oysters, these shellfish sometimes produce a small ball of shiny shell material around an irritating object. Freshwater pearls are not as highly prized as those from saltwater shellfish, as they are considered to be less lustrous. Most modern pearls are produced in shellfish farms.

New animals are still arriving in Ireland and making themselves at home here. Zebra mussels are freshwater shellfish that originated in rivers around the Black Sea and Caspian Sea. They spread across Europe as canals were built, reaching Britain in 1830. It was not until the 1990s that zebra mussels started to spread through Ireland. They are now a major pest, occurring in huge numbers, up to 100,000 per square metre. Alien species often upset the balance of nature when they are moved to new areas without their normal predators.

Occasional oddities on display included a lobster, which has developed with normal coloration only along one side.

Insect Life

Ireland has about 12,000 different species of insect. One of the key roles of the Museum is to help scientists identify animals. It is important to identify each species correctly in order to control pests. Many insects play an important part in keeping nature in balance. They pollinate plants and control other harmful insect species. Regular monitoring of insects gives us a measure of the health of our environment. The common blue butterfly Polyommatus icarus is an indicator of healthy grasslands.

A record specimen of a trout was taken from Lough Ennell, Co. Westmeath, on 15 August 1894 by William Meares. It weighed 11.8kg when caught and still holds the record despite many challenges. One challenge came from a salmon that was mistaken for a trout. This fish is known as Pepper’s Ghost, and, at more than 13.8kg, it had claimed the record since 1861. Scientific examination of its scales confirmed that Pepper’s Ghost was in fact a salmon. This story shows another use for the Museum’s collection – finding the truth behind fishy tales!