Where did today's horses come from? Scientists can read the DNA of horses that lived long ago to find out. A 2021 ancient-DNA study found that today's domestic horses were first domesticated in the Pontic-Caspian steppes, northern Caucasus. The study analysed the genomes of 273 horses. They lived between 50,000 and 200 years BC. DNA also showed that the 5,500-year-old horses from Botai, Central Asia, were not the ancestors of modern domestic horses. People ride horses, and a rider should wear a helmet every time and have a grown-up instructor nearby.

DNA also tells a story about Przewalski's horses. They live in groups with several mares, a dominant stallion, and their young. They eat mostly grass and some leaves. They disappeared from the wild, and the last were seen in the late 1960s. Later they were reintroduced to Mongolia. A 2018 DNA study suggested something about them. It suggested that they descend from early domestic Botai herds that escaped. They do not come from horses that were never tamed.

The oldest known horse was Hyracotherium. It was a small, dog-sized animal that lived in forests and ate leaves. It lived from around 55 million years ago to around 45 million years ago. It had 4 toes on each front foot and 3 toes on each hind foot. Over millions of years the ancestors of horses lost toes. Modern horses have only one toe on each foot. Horses are grazers that mostly eat grass.

Now look at wild horses today. They live in herds of one or two stallions, a group of mares, and their foals. In a herd, some horses lie down while at least one stays standing to watch for danger. Horses are prey animals that depend on running away to stay safe. The Spanish brought horses back to North America in the 1500s. Most wild horses and burros living today descend from animals released or escaped from people such as Spanish explorers.

Words to know

• genomes: full DNA sets
• domesticated: tamed for people
• reintroduced: brought back
• ancestors: earlier relatives
• burros: small donkeys