— My dear little goats, did you drink or eat? — asks the old farmer as the goats return from the pasture.
And they shake their beards and, without batting an eye, reply:
— We neither drank nor ate. We ran across the little bridge, grabbed a maple leaf, and dashed over the dam… and the old man chased away the shepherd…
That’s from a fairy tale. But while those tales are charming, scientists can determine how animals such as sheep are raised and what they eat over the course of a year.
The fine wool of a sheep grows about 10 millimeters each month. Undernourishment or illness shows up in the wool as thinning, while abundant nutrition causes the wool to thicken. All of these changes can be seen under a microscope. Measuring the wool at specific points reveals how the animal was fed not just over the course of a year, but month by month.
