Mules

Mules are still used when people want a calmer, safer animal than a horse, or one more sure-footed for mountain trails.

Grand canyon mule train.
http://commons.wikimedia.org/wiki/File:Grandcanyon-mules.jpg

Mules are a cross between a female horse (mare), . . .
Horses Photo: These horses are for adoption.
http://commons.wikimedia.org/wiki/File:Mustangs_palomino_valley_center.jpg

. . . and a male donkey (Jack).
Photo of baby donkey with winter coat back from around face.
You can adopt inexpensive donkeys (burros) form the BLM.
http://commons.wikimedia.org/wiki/File:Burrito_de_p%C3%A1ramo_(P%C3%A1ramo_baby_donkey).jpg

If you cross a female donkey with a male horse, you get a hinny:
http://commons.wikimedia.org/wiki/File:Old_mule_in_Oklahoma.jpg

Here is how I tell the difference:

Horses have long hair all over their tail.
http://commons.wikimedia.org/wiki/File:Welsh_Cob_with_swingletree.JPG

Donkeys only have long hair on the bottom part of their tail.
http://commons.wikimedia.org/wiki/File:Donkey-09.jpg

This donkey is in winter coat, but the longer hairs are still only on the tip half of the tail:
http://commons.wikimedia.org/wiki/File:Donkey.jpg

Mules & Hinnies have the tail of their father.
Mules have a donkey's tail.
Hinnies have a horse's tail.

Mules & Hinnies tend to have the size of their mother.
Mules are usually taller than Hinnies, like ligers are bigger than tions.
But there are different sizes of donkeys, and different sizes of horses, so this only applies to the crossing of regular size donkeys and horses.

YOU HAVE TO SEE THIS PHOTO! I love action photos of animals.
http://commons.wikimedia.org/wiki/File:Horse-and-pony.jpg