EARLY, WILD AND FERAL HORSES

About 60 million years ago, a timid four-legged mammal, no bigger than a hare, browsed the forests of North America. Palaeontologists believe this creature, the Dawn Horse, was an ancestor of the horses we see today (as well as being related to tapirs and rhinoceroses!).

Dawn horse

Hyracotherium, the Dawn Horse, could be found in North America 50 million years ago (mya). Small teeth show it was a browser, probably favouring soft leaves and fruit.

Middle horse

Looking back 40 million years sees the emergence of Mesohippus, slightly larger than the Dawn Horse at about the size of a sheep. This animal wandered a more open landscape, with fewer forests.

One-toed horse

This creature, Pliohippus, was about the size of a donkey and lived between ten and five mya. It had longer, stronger teeth, to cope with the tougher vegetation of a drier climate. It probably roamed open plains.

Equus

A more recognizable ancestor of today’s horses appeared some four mya. Equus was the size of a pony, and, with its longer legs, an adept runner over the larger areas of grassland that had changed the landscape.

Reaching new places

Equus emerged in North America, so how did its descendents spread? They migrated via Ice Age land bridges. When the ice receded (some 10,000 years ago), the horse disappeared in North America. No one knows why. It was reintroduced in the 1600s.

WILD HORSES

Horses ran wild for thousands of years before being tamed by humans. There are now no wild horses, though some experts think the Przewalski’s horse – a primitive horse that still survives – is related to these early breeds.

Wild origins

Also known as the Asian wild horse, Przewalski’s horse has been extinct in the wild since the 1960s, but groups are gradually being released from small captive herds.

One big family

Equidae, the horse family, includes four types of horse – Przewalski’s horse, domestic horses (including ponies), asses, and zebras.

Przewakski's Horse
These horses have short manes and no forelock.

Asses
There are three types of ass: the African wild ass, the kiang, shown here, and the onager.

Zebra
This is the one truly wild member of the horse family.

A true survivor

Like its wild ancestors, an African wild ass is tough. It can survive for two or three days without water, living on almost any plant material.

It’s just a zebra!

You may think that all zebras are alike, but in fact there are three species of zebra and each species has a different pattern of stripes. In fact, no two zebras have the same pattern of stripes (just like humans have unique fingerprints).

Grevy's Zebra - The largest of the zebra family.

Plains Zebra - The most common of all zebras.

Mountain Zebra - Has a fold of skin, a dewlap, on its dewlap, on its throat.

Can a zebra be tamed?

Zebras have not been successfully trained to work for humans apart from in a few cases. That’s because they tend to get aggressive as they get older and they panic easily.

FERAL HORSES 

Herds of mustang horses roam western American plains. These are feral horses; the descendants of domestic horses. Feral horse herds can be found all over the world.

Route to America

Horses were first brought to North America by Spanish conquistadors about 400 years ago. Some escaped or were set free, and by 1900 there were about two million feral horses in the US. Mustangs were seen as pests and many were killed. They are now protected by law.

Who’s the boss?

All horses prefer not to fight, but in a feral herd the dominant stallion will do so in order to maintain his position over a group of mares. Usually the weaker horse backs off pretty speedily.

French feral herds

Sometimes referred to as “the horse of the sea”, semi-feral Camargue horses roam saltwater marshland in southeastern France. Adults are grey, but foals are coloured brown or black and turn grey as they get older.

Route to Australia

Feral horses are known as “brumbies” in Australia and there are lots of them – far more than any other feral horse elsewhere. Horses first arrived in Australia in 1788 on the First Fleet, eleven ships that sailed to Australia from Great Britain. There were just seven of them. By 1850 they numbered 160,000 (due to breeding) and there are now some 400,000 feral horses in Australia.

Written and edited by Caroline Stamps in "Horse", first published in Great Britain in 2010 by Dorling Kindersley Limited, London, excerpts p. 22-28. Adapted and illustrated to be posted by Leopoldo Costa.