Twenty-two horses in Norway can tell you whether they want to wear a blanket or stick with bare backs, according to a new study.

This is, needless to say, a handy skill for anyone who resides in a northern nation that gets a lot of snow. But its discovery is also an important addition to understanding of horse smarts and learning abilities, according to researchers at the Norwegian Veterinary Institute. They taught the horses to use symbols to indicate their blanket-wearing preference โ€” and the equinesโ€™ easy mastery of the task suggests they understood that the symbols had meanings that led to outcomes.

โ€œOur aim was … to develop a tool to โ€˜askโ€™ horses whether or not they prefer to wear a blanket under different weather conditions,โ€ the authors wrote in Applied Animal Behaviour Science. In the end, they added: โ€œHorses chose to stay without a blanket in nice weather, and they chose to have a blanket on when the weather was wet, windy and cold.โ€

The subjects were 22 ordinary riding horses with charming names including Poltergeist, Virvelvind and Romano. All had previous experience wearing blankets when their owners deemed them necessary. To help the horses express their own preferences, the researchers created three simple boards: One with a horizontal bar meant โ€œput blanket on;โ€ an unmarked board meant โ€œno change;โ€ and a board with a vertical bar meant โ€œtake blanket off.โ€

Then the horses went through a methodical literacy course of sorts. First, the trainers introduced the symbols one at a time. Horses that touched it with their muzzles would be rewarded with a thin slice of carrot, and then the corresponding action would be carried out โ€” the blanket taken on or off. Once the horses had that down, they were shown both symbols at the same time, but they only got their treats if they touched the โ€œrelevantโ€ one. In other words, if a horse wearing a blanket touched the symbol that meant โ€œput a blanket on,โ€ heโ€™d get nothing.

Next, the researchers introduced temperature to the equation. Horses were draped in thick blankets that made them sweaty and โ€œobviously hot,โ€ or they were put outside in what the Norwegians called โ€œchallenging weatherโ€ โ€” so it really must have been awful โ€” until they tensed, tucked in their tails or showed other signs of being cold. They had to pick the relevant symbol 12 times to move onto the next step, which was meeting the blank โ€œno changeโ€ board.

Picking that one always earned a carrot, but never a blanket status change.

After that, the horses saw all three boards in various combinations and locations, and only relevant choices led to snacks. Then they were given a โ€œfree choiceโ€ between two relevant symbols.

โ€œIn total, these results strongly indicate that the horses had learnt to communicate their preferences using symbols,โ€ the authors wrote. The horses learned this all in just 10-15 minutes of daily training over 14 days. A few class clowns slowed things down.

Poltergeist and Runa learned so fast that they โ€œbegan to explore other possibilities and solutions to earn more carrot slices,โ€ such as nibbling on the boards, and โ€œneeded time to be convinced that there were none,โ€ the study said.

And Blue โ€œseemed to enjoy the event of blankets taken on and off, as he always touched the โ€˜changeโ€™ symbol.โ€ But with a few extra hot and cold tests, Blue figured out that choices have consequences โ€” in this case, sweat, shivers or just the right amount of toastiness.