Horses in an experiment have been shown when they feel cold and need a blanket by pointing with their heads to a symbol – a horizontal black line.
They were also able to communicate two other possibilities: that they wanted their blanket taken off – a vertical line, or ‘no change’ – a blank symbol.
The research in Applied Animal Behaviour Science found 23 horses in the trial learned the task after training for just 10 to 15 minutes a day over two weeks.
The horses were taught to associate putting the blanket on and off with the symbol by being rewarded with slices of carrot.
And the researchers found the selection of the symbol was not random, but was dependent on the weather.
Horses opted for a blanket when the weather was wet, windy and cold.
Cecilie Mejdell, of the Norwegian Veterinary Institute and colleagues carried out the study.
To test whether the horses had learnt the meaning of the symbols, they were let out of their paddocks for two hours, to become fully aware of the weather.