Why do dog/cat ears twitch when air passes over them?

Question

While I was in bed last night with my Pitbull, she had her head up near my face. My nose was simply exhaling air near her ear, which caused it to repeatedly twitch. If I exhaled more air, it would keep twitching, to the point where she would move her head. I've noticed this back when I used to live with cats as well. The same thing would occur with them.

Why do dog/cat ears twitch when air passed over them? Do they have some sort of reflect or are they just more sensitive? I will say that when I am exhaling at a normal rate, the air flow isn't that fast. I can understand that it may be more annoying when I purposely exhale faster.

Answer 1

Have you ever been to a farm with cows or horses and their muscles twitch when a fly lands on them? Just like in horses and cows this is a simple muscular reflex. Cats have 32 muscles in their ears and dogs have over a dozen. Although it doesn't look "beefy" or built-up, the muscles have a stronger reflex sensitivity than humans have. They're brain is telling them they have an itch or discomfort, and it's not even a conscious action. If irritated enough they'll run they're paws over the ear to calm the nerves and relieve the itch or discomfort. Rubbing produces more blood flow and heat to the affected area.