One big moment in every child’s life is when they finally realize that the number of humps on a camel’s back isn’t random. Some have one, some have two—and they’re actually two different species. The single-humped ones are called dromedaries. After this discovery, kids start choosing their stuffed animals more carefully, confidently correct their grandparents about the humps, and, of course, never go looking for two humps in the dromedary enclosure at the zoo again.