The hinny is the offspring of a stallion and a jenny or female donkey, and is thus the
reciprocal cross to the more common mule foaled by a jack (male donkey) out of a
mare. Like the mule, the hinny displays
hybrid vigour (heterosis). In general terms, in both these hybrids the foreparts and head of the animal are similar to those of the sire, while the hindparts and tail are more similar to those of the dam. A hinny is generally smaller than a mule, with shorter ears and a lighter head; the tail is tasselled like that of its donkey mother. The distinct
phenotypes of the hinny and the mule are partly attributable to genomic imprinting – an element of
epigenetic inheritance. Hinnies and mules differ in temperament despite sharing
nuclear genomes; this too is believed to be attributable to the action of imprinted genes. == Fertility, sterility and rarity ==