Sheep earwax can record a dangerous diet

A quick swab may tell ranchers if their livestock are eating a sinister salad on the range

Four sheep graze in a meadow of tall grass dotted by yellow flowers

Free-choice eating sheep like these near Ashton, Idaho can encounter toxic death camas (the sprays of pale yellow flowers) while eating. A simple earwax test could help ranchers protect livestock and identify risky grazing patterns.

Clint Stonecipher

A bit of ear goop can reveal if sheep are eating dangerously poisonous plants.