Page 206 - The Miracle of Migration in Animals

THE MIRACLE OF MIGRATION IN ANIMALS

Lemmings: North’s Small Migrants

These herbivorous rodents that inhabit the tundra zones of
the North Pole and the Alps live in large communities, and regu-
larly migrate as a group.
Lemmings are seasonal migrators. In winter, they live in dry
places or on rocky slopes with a thick covering of snow. When the
snowmelt starts filling their underground burrows, they move to
moist summer pastures next to rivers or bogs. At the end of the
breeding season, they move back to the winter grounds. This mi-
gration begins in July and lasts several months. First the adult
males leave the region, followed by the females and finally, the
young lemmings. When the number of lemmings is low, their mi-
gration does not last long. But every three to four years the num-
bers greatly increase, and they can migrate over very great
distances. 55

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