What are horses that dark brown with black manes called?

Horses that are dark brown with black manes and tails are typically called bay horses.

Here's why:

* Bay is a horse coat color characterized by a brown body, a black mane and tail, and black points (legs, muzzle, and sometimes ears).

* The shade of brown can vary significantly, from light bay to dark bay, almost black.

There are other horse colors that could be confused with bay, but the key features are the black mane and tail in combination with the brown body.