3
Reading Passage 2
Read the passage about animal migrations.
Nature’s Most Impressive Animal Migrations
1
Arctic terns are tiny birds weighing between 90–120 grams with a wing length of
64–76 centimetres. They do not look strong, but these birds take the prize for the longest
migration of any animal in the world. Arctic terns spend most of their year at
sea flying after
a never-ending summer. Arctic terns are believed to migrate around 40,000 kilometres a
year, but a new scientific study suggests that they might fly double that distance.
2
Each year, millions of monarch butterflies leave their northern ranges and fly south to the
forests near the Sierra Madre Mountains, where they gather in huge roosts (groups) to
survive the winter. When spring arrives, the monarchs start their return journey north; it
takes three to five generations of the population to reach their destination. Along the way,
females lay eggs. The new generation of butterflies complete the journey their great-great-
great-grandparents started. They navigate using the Earth’s magnetic field.
3
Wildebeest (gnu) are
members of the antelope family, but they look more like cows with
their big horns, thick body, and hairy heads. They live in huge herds (groups) of over one
million individuals, along with thousands of zebras and gazelles. During the dry season, this
giant herd travels the Serengeti-Mara ecosystem of Tanzania and Kenya in search of fresh
grass and water. It is a round-trip that extends over hundreds of miles and two countries.
When the herd moves, individuals must keep up, otherwise they risk being picked off by the
lions, hyenas, and crocodiles.
4
Humpback whales are one of the largest animals on
the planet, weighing in at an impressive
36,000 kilograms. These giants migrate to warmer waters to raise their babies and avoid
killer whales’ attacks. It is a journey that can take over 8,000 kilometres each way, making it
the longest migration of any mammal on Earth. Humpback whales are slow swimmers, but
they make up for it by traveling non-stop for days at a time. They do not feed along their
migration route and instead survive on fat reserves built up during the summer months.
5
Salmon spend most of their lives in the Atlantic and Pacific oceans, before migrating back to
the rivers where they were born. Salmon swim across the ocean to the mouth of the river. To
reach their final destination, the salmon must swim up the river, in an event known as ‘the
salmon run’. With incredible strength, they swim up to 400
kilometres against the flow,
fast-moving water and jumping up waterfalls, all while avoiding hunters like bears. When
they finally reach their birthplace, the salmon lay fish eggs and then die.
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