St Kilda field mouse facts for kids
Quick facts for kids St Kilda field mouse |
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Apodemus
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A. s. hirtensis
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| Apodemus sylvaticus hirtensis (Barrett-Hamilton, 1899)
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The St Kilda field mouse (Apodemus sylvaticus hirtensis) is a special type of wood mouse. It is a subspecies, which means it's a group of animals within a species that has unique features. This mouse lives only on the St Kilda islands in Scotland. This means it is endemic to St Kilda.
St Kilda is an archipelago, a group of islands, located about 40 miles (64 km) west of Benbecula in the Outer Hebrides. It's also about 100 miles (160 km) from mainland Scotland. People believe these mice first arrived on the islands over a thousand years ago. They likely came on the boats of Viking settlers. It's important not to mix them up with the St Kilda house mouse, which is now extinct.
The last people living on St Kilda left the islands on August 29, 1930. After they left, the house mice, which depended on humans for food, could not survive. They died out within two years. But the St Kilda field mice, which usually live in the wild, moved into the empty houses. They were able to survive the tough island conditions.
Today, people sometimes visit St Kilda, but there are no permanent residents. The field mice are very common on the main island, Hirta. You can find them everywhere, from the harbor to the highest points. They are especially common in the old village areas, where they can get into buildings through holes. Even though they are common, visitors don't often see them.
What Does the St Kilda Field Mouse Look Like?
This mouse has black eyes and small, pointy ears. Its fur is mostly brown, but its belly is a lighter color. It's much bigger and heavier than field mice you might find on the mainland. A St Kilda field mouse can weigh between 50 grams (1.8 oz) and 70 grams (2.5 oz). That's about twice as heavy as other field mice!
It also has longer fur and a longer tail. These mice can grow up to about 17 cm (6.7 in) long. They are found all over the main island of Hirta and also on the island of Dùn. However, you won't find them on Boreray.
Why are they so big? On St Kilda, there are not many animals that hunt mice. This means the mice can grow larger. Being bigger helps them stay warm and store more fat, which is important in a cold island environment. This is a special kind of growth called island gigantism.
What Do St Kilda Field Mice Eat?
The St Kilda field mouse is an omnivore, which means it eats both plants and animals. It's not picky about its food! Its diet includes insects, snails, and seeds. They also eat moss. Sometimes, they even eat human trash or dead animals.
There is only one other native mammal on the islands, the Soay sheep. These sheep eat grasses and herbs. This means the St Kilda field mouse doesn't have much competition for food. They have plenty to eat on the islands.
History of the St Kilda Field Mouse
As we mentioned, people believe the ancestors of these mice came to St Kilda on Viking ships. A scientist named Gerald Edwin Hamilton Barrett-Hamilton first described this mouse in 1899. He thought it was a completely new species and called it Apodemus hirtensis.
But just one year later, after more studies, it was decided that it was a subspecies of the common wood mouse. So, its name became Apodemus sylvaticus hirtensis.
Scientists have studied the mouse populations on St Kilda many times, including in 1931, 1939, and 1955. These studies showed how quickly the St Kilda house mouse died out after humans left. The field mouse then took over the areas where the house mouse used to live. This is called niche expansion, where an animal starts using new parts of its habitat.
