Kimo and the black truck

I'm noticing that Kimo doesn't like black trucks.

The other day the pilot was driving a black truck and Kimo charged after it as it passed.

Then yesterday I was holding Kimo as Keith was walking and a black truck went up and parked up the street. Kimo went wild and I had to grab his collar and hold him until he calmed down. I didn't notice Keith going wild. So maybe he was already charged up with the black truck in sight(?)