Equus giganteus - the giant horse

Two Scott's horse (E. scotti) stallions are about to duke it out over a mare when they're suddenly interrupted by a mare Equus giganteus, the giant ice age horse. Though she is a mare, she stands taller than either of the Scott stallions and their mare can do nothing but stand in admiration of her larger sister species. 
Equus giganteus was the largest species of wild horse to ever exist. Standing up to 2 m (6.6 ft) tall at the shoulder and weighing 1200-1500 kg (2600-3300 lb) it was as large as present day draft horses, which was likely an adaptation to protect itself from large predators such as American lions and giant short-faced bears. It lived across the many plains of North America during the last ice age and likely went extinct around 12,000 years ago.