Animal · Mexico, United States, Canada
Monarch butterfly
Danaus plexippus — the name this animal has in the language scientists everywhere share.
The monarch butterfly is famous for its incredible multi-generational migration between North America and Mexico. Its bright orange and black wings warn predators that it is unpleasant to eat.
Picture credit: Thomas Bresson (CC BY 2.0) · Wikimedia Commons
Where does the monarch butterfly live?
Home: Meadows and forests across North America, migrating to Mexico.
In the wild you find it in: Mexico, United States, Canada.
Conservation status from the IUCN: vulnerable.
The short profile
Fully grown it measures Wingspan 9–10 cm. It weighs about 0 001 kilograms. On the menu: plants.
The story behind it
No single monarch butterfly completes the entire migration; instead, it takes three or four generations to fly north from Mexico to Canada over the summer, before a special final 'super generation' is born that can live up to eight months, long enough to fly all the way back to the very same forests in Mexico that its great-great-grandparents left, without ever having been there before. Monarch caterpillars eat only milkweed, absorbing toxins from the plant that stay in their body through to adulthood, making the adult butterfly poisonous enough to make predators sick, which is why its bold orange and black pattern works as a warning. Millions of monarchs cluster together on oyamel fir trees in central Mexico each winter, so densely that branches can bend under their weight. Loss of milkweed and winter forest habitat has caused sharp declines, and the migratory population is now considered vulnerable.
Find it on the globe
Monarch butterfly is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.
It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.
Questions children ask
How do monarch butterflies find their way to Mexico if they've never been there?
No individual monarch makes the whole round trip. It takes several generations to travel north each summer, and a final long-lived generation instinctively flies south to the exact same Mexican forests their ancestors used, guided by the sun and Earth's magnetic field.
Why are monarch butterflies poisonous?
Monarch caterpillars eat only milkweed, which contains toxins that stay in their body into adulthood. This makes the butterfly taste bad and can make predators sick, and its bright orange and black colours warn them to stay away.
Why are monarch butterflies vulnerable?
Monarch butterflies are vulnerable mainly because milkweed, the only plant their caterpillars eat, has become scarcer due to farming and pesticide use, and their winter forest habitat in Mexico is also shrinking, threatening the whole migration.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
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