Why are people long in the tooth?

Because old horses are. Horses have open rooted teeth that grow through their lives. (Some old horses will outlive their teeth - at which point they really need special food so they can gum it properly).

So, the saying "long in the tooth" originally referred to horses and then came to refer to people (and dogs, cats, etc).

What is a dark horse?

You might have heard the term "dark horse" for somebody who unexpectedly rises to prominence or suddenly comes under scrutiny.

It's a racing term, used of a horse that doesn't have a good record - and thus is very hard to bet on. When a dark horse wins, of course...so does the house.

What is a "spavined" horse?

A spavined horse is a lame one, especially a permanently lame one. The term has an interesting origin.

It's actually French. When a horse has a bad hock injury or bad arthritis in the hock, their gait behind starts to resemble that of a hopping sparrow. The French word for sparrow is "espavain."

Hence, a "spavined" horse is one that moves like a sparrow - and as it's most often associated with arthritis in the hock, it's sometimes used as a term for any horse that has a serious or long term injury that affects its ability to work.

Why is racing over fences called steeplechasing?

The term actually originates in Britain and Ireland. The first races were run over open countryside, with horses clearing whatever obstacles were in their path. They were intended as a test of hunters - in fact, in the United Kingdom amateur steeplechase mounts still have to qualify by attending a certain number of hunt meets each year.

The races were generally run from one village to another - and riders would navigate by pointing their horse at the church steeple.

What is mounted orienteering?

Orienteering is a sport in which you have to cross unknown territory with only a map and a compass. So, of course, some people do it on horseback. (The rules are slightly different, but basically you have to get from point A to point B whilst passing through several intermediary points).

It's somewhat popular in America but unusual in Europe these days (probably because of lack of space). Like many equestrian sports, it grew out of skills useful to a cavalry officer.

What is tent pegging?

Tent pegging is any contest that involves a horse and some kind of bladed weapon. Although horses aren't used in cavalry any more, some of the skills are still preserved.

Most specifically, tent pegging means riding at a gallop with a sword or lance and picking up a small ground target. Without slowing down. More advanced riders might use multiple targets. It originated in India.

(Needless to say, you don't want your horse to be too tall for this).

Image source: Mike Bostock via Wikimedia Commons.

Do horses wear snowshoes?

Equine snowshoes do exist. They're generally either hoof shaped or square and used to be made of wood. They were invented for logging in winter in Canada and the Midwest. (And are often attributed to Paul Bunyan).

Early snowshoes strapped to the hoof with leather. Later ones were actually attached to the hoof.

The snowshoes would not just increase the horse's ability to pull in deep snow but also prevent snow from balling in the hoof, which can make a horse slip (and annoy them).