"A mule is the offspring of a male donkey (jack) and a female horse (mare). Horses and donkeys are different species, with different numbers of chromosomes. ...
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Of the two first-generation hybrids between these two species, a mule is easier to obtain than a hinny, which is the offspring of a female donkey (jenny) and a male horse (stallion).
The size of a mule and work to which it is put depend largely on the breeding of the mule´s female parent (dam). Mules can be lightweight, medium weight or when produced from draft horse mares, of moderately heavy weight.:85–87 Mules are reputed to be more patient, hardy and long-lived than horses and are described as less obstinate and more intelligent than donkeys.:5" - (en.wikipedia.org 21.12.2020)