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Understanding and Caring for Donkeys and Mules

Mule Terminology, Characteristics and Differences


There are estimated to be 50 million donkeys (Equus asinus) and as many mules worldwide. They can be used for such applications as riding, driving, flock protection, companion, breeding, and training calves. Donkeys and mules are not small horses. They have anatomical and physiological differences compared to horses and their care requires special consideration. Structural differences compared to horses mean that they require specialized tack and harness for riding and driving (1).


Jack: Male donkey

  • Jennet or Jenny (both pronounced the same): Female donkey
  • Donkey gelding: Castrated male donkey
  • Mule: The offspring of the mating of a jack with a mare (female horse)
  • Hinny: The offspring of the mating of a stallion (male horse) with a jennet

Mature animals can be further designated into the following classifications based on height measured at the withers:

  • Miniature: under 36 inches
  • Small Standard: from 36.01 to 48 inches
  • Large Standard: over 48 inches and under 54 inches for females; over 48 inches and under 56 inches for jacks and geldings
  • Mammoth: 54 inches or over for females and 56 inches or over for male

For more information on registration guidelines, contact the Canadian Donkey and Mule Association (http://www.donkeyandmule.com/).

Anatomical Differences Between Horses and Donkeys

A number of anatomical differences can challenge the first-time donkey owner and their veterinarian. Two of these include:
  1. An obscured jugular furrow (the place where blood samples are taken or tranquilizers are given). The cutaneous coli muscle is much thicker than in the horse and hides the middle third of the jugular vein. It is easier to find the upper third of the jugular.
  2. The nasolacrimal duct of the donkey is located on the flare of the nostril rather than the floor of the nostril as it is in the horse (2).


Donkeys and mules are known to be very stoic animals that are slow to show pain and discomfort. While these characteristics may be desirable in many cases, it can lead to problems identifying a sick animal. The attributes we assign to a donkey being stubborn and having a lack of intelligence are actually from their natural responses to new experiences and logical interpretation of a situation. Being tough animals, they will kick easily and swiftly (2). Donkeys and mules are very social animals and will benefit tremendously from the companionship of other animals, such as horses, cattle, sheep or goats.

Authors: Heather McClinchey MSx; Jeffrey Sankey , BSc, Ontario Veterinary College, Unversity of Guelph, Guelph, Ontario, Canada and Dr. Bob Wright, Ontario Ministry of Agriculture and Food, Fergus, Ontario, Canada

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