Eagle
Reference: Bird anatomy
Better lungs than a mammal, one more dimension of colour than a human, and hands so thoroughly converted to wings that it must carry everything in its feet.
Scored on every axis
The best lung in the catalogue
Birds do not have alveoli or tidal breathing. Air sacs drive a one-way flow through rigid tubes, so the exchange surface always meets fresh air rather than a mixture of fresh and stale. It is a straightforwardly superior arrangement to the mammalian lung — the reason birds fly at altitudes where a mammal would lose consciousness.
Combined with hollow, air-filled bones and a keeled sternum anchoring the flight muscles, the whole body is built around the one activity.
Four-dimensional colour, and two centres of focus
Like most birds the eagle is a tetrachromat, with a fourth photoreceptor class reaching into ultraviolet — a dimension of colour humans have no access to and cannot picture. Each eye also carries two foveae, one for forward binocular work and one for sideways scanning, and acuity runs to several times human.
Set against the horse, this is the predator end of the same axis: forward-facing, high acuity, depth over coverage.