An ostrich’s eye is bigger than its brain

At 5 cm in diameter, (slightly larger than a golf ball) the ostrich has the largest eye of any land animal. In comparison, the average human eye is about 2.4 cm in diameter.

While its true that a single ostrich eye is larger than its brain, it’s not really fair to single the ostrich out. Several other birds, like the sparrow have eyes that are nearly as big as their brains.

Vision is extremely important in all birds. Avoiding predators, searching for prey, and flying quickly (or running in the case of the ostrich) requires excellent vision. Large eyes allow birds to see more of their environment. Ostriches can run up to 70 kph (44 mph) making them the fastest running bird and putting them among the fastest land animals. Seeing where they are going is very important.