End Of The Line
Any hybrid cross between Equus Caballus (the horse) and Equus Asinus (the donkey) can be labeled a "mule". Typically, these hybrids are sterile and cannot reproduce, but, like any rule, there have been reports of "exceptions" resulting in a "hule" or "jule". Confused?
- A male ass, or "jack" is usually crossed with a female horse, or "mare", resulting in a hybrid offspring that is not fertile and cannot reproduce.
- A "stud" horse bred to a female or "jennet" ass, produces a hybrid often called a "hinny"; also infertile.
- Then too, there's the Zebroid hybrid; sometimes called a "zorse". You guessed it. It's the offspring of a zebra stud and out of either a mare or a jennet. It too is sterile.
All of these hybrid crosses do have either male or female genitals and a normal sex drive. They will even breed, but don't conceive. Castrating jacks is usually advisable since this helps to avoid "dangerous stud" situations.
Mules and hinnys have 63 chromosomes as opposed to the 62 chromosomes possessed by the donkey; and the horse's chromosome count is 64. Because the number and structure of the chromosomes possesed by horses and donkeys differ so, creating successful embryos is pretty much an impossibility.
Although there have been "documented" reports over the centuries with claims of "molly" mules or "molly" hinnys producing successful foals by purebred stallions, nearly always a cross between the species is the end of the line.