Figure 11. The mule results from
crossing a female caballine horse and a male donkey. It is generally stronger than either of
its parents and is therefore used extensively for work.
This photo shows a mule that pulls barges along a canal in Ohio. An
early American folk song "Erie Canal" mentions these animals:
"I've got a mule, her name is Sal
15 miles on the Erie Canal.
She's a good old worker and a good old pal
15 miles on the Erie Canal
We've hauled some barges in our day
Filled with lumber, coal, and hay
And we know every inch of the way
From Albany to Buffalo."
Photograph by Marlene Barrett (USA).