Horses make their riders understand that they understand their commands and that they are even able to pick up a spear from the ground and pass it to the rider.
Pliny also gives an interesting story from the reign of Emperor Claudius (41-54 CE), when the chariot races were organized in Circus Maximus. Namely, already at the start, the coachman of the “white” team fell out of the harness, but despite the lack of a human being, the horses ran in the race and took first place. What’s more, during the race they used tricks learned during training, such as scaring horses from the opposite team or taking the road. Finally, instead of running across the finish line, they stopped in front of the chalk line, as Pliny argues, so as not to embarrass people that horses were able to win on their own.