I took a look in the newspapers at how the word bellwether was being used.

• The shopping trends between American Thanksgiving and Christmas are said to be a bellwether of the economy.
• The number of Harvard grads taking jobs in the financial sector was said to be a kind of bellwether of the markets.

The American Heritage Dictionary defines a bellwether as: “one that serves as a leader or as a leading indicator of future trends.”

Before we peek into the dictionary and find out what the real etymology might be for this word, let’s take a moment and use our imaginations.  What possible sources might have come into play that could make the word bellwether mean an indicator of future trends?

My mind drifted to images of glass instruments used by ships captains to predict changes in the weather; something bell-shaped. Some old barometers looked like glass teapots or watering cans.  Changes in air pressure makes the fluid in the spout raise up higher or sink down lower.  Maybe a bellwether was something like that.

Okay, now for the truth.

A bellwether had nothing to do with sea captains or even the weather for that matter.  It had to do with sheep farming.

Farmers sometimes do things to their animals that might seem cruel to city folk.  One of these is castrating the young males.

This might be done so that the farmer can control when females get pregnant, to reduce fighting among males, or in the case of sheep, to make it easier to shave off the fleece at sheering time without accidentally getting the ram’s scrotum caught up in the clippers.

Often sheep’s tails are docked too and their bums regularly clipped to keep them from getting filthy with poo.

It’s best to do the docking and castrating when the animal is young.  For one thing, there’s less fight in them.

This has been going on long enough that the word used for “a castrated sheep” in the Germanic precursor languages to Old English became wether.

It’s thought that this is because an Indo-European root of the word had meant “year” and these young animals were yearlings.

Evidently with or without castration a male sheep still wants to be a leader in his flock and once the sheepy social niceties have been worked out one of the males in any flock emerges as the leader, after whom the rest follow like sheep.

A shepherd who wants to know where his or her sheep might be headed would be smart to tie a bell onto that lead sheep.  Hence, by the bellwether the future trend of the flock will be known.