Monarch butterflies have magnitite (a mineral) inside their heads and this helps them determine 'North', just like a magnet.
Going, going
Going, going Fish, crayfish, water snails, mussels and
amphibians who live in North America's lakes, streams and rivers
may be in danger of extinction. Factors such as pollution, dam
construction and introduction of exotic species all have an effect
on the future survival of native species. 9 OCTOBER 1999, P. 27
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