If you cross a mule and a horse, you get a donkey. How many chromosomes does a donkey have?

horse=64 chromosomes

mule=63 chromosomes

62

Explanation:

31 pairs

A mule is the offspring of a male donkey (a jack) and a female horse (a mare). A horse has 64 chromosomes, and a donkey has 62. The mule ends up with 63. Mules can be either male or female, but, because of the odd number of chromosomes, they can't reproduce.