According to a new study, they whistle. Researchers slid a small camera through horses' noses to film what happened inside while they whinnied and made another common horse sound, the softer, subtler ...
A few small rodents like rats and mice whistle like this, but horses are the first known large mammal to have a knack for it.
Cold weather drives rodents to seek warmth in engine bays, where they chew wiring and build nests from leaves, sticks and insulation.