How Many Millions of Monarch Butterflies?

Scientists can only estimate how many millions of butterflies are in a monarch colony. They say a colony contains between 10 and 50 million monarchs per hectare of forest. One hectare is 2.47 acres, about the size of two and a half football fields.

Every winter, scientists visit the 12 sanctuaries and measure the area of forest covered by monarchs. The colonies covered a total of .67 hectares of forest in December 2013. How many millions of monarch butterflies were there?


A monarch colony covers the trees in the El Rosario monarch sanctuary.

  • A monarch colony is a large cluster of butterflies.
  • A monarch sanctuary refers to the whole forest within which the colony moves.

Try This! Monarch Math
Estimate the number of butterflies in .67 hectares of forest.

  • If there are 10 million monarchs per hectare there would be ____________ million monarch butterflies wintering in Mexico.

 

  • If there are 50 million monarchs per hectare there would be ____________ million monarch butterflies wintering in Mexico.

 

  • Based on these estimates, there are between _________________ and _________________ monarch butterflies wintering in Mexico.

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