Sheep wander through a field blanketed with ash from the eruption of the Chaitén volcano in Futaleufú, Chile, on May 9, 2008.

Small farmers living in the remote agricultural valleys near the volcano have been evacuated and forced to leave behind tens of thousands of animals—including pets.

But an estimated 15,331 head of cattle, 12,828 sheep, and 957 horses have been targeted for evacuation, an official from Chile's agriculture ministry told National Geographic News on Thursday.

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