Yes, Cub Scouts is one of those:

Tiger Cub: must be under age 8, have completed K or be in 1st, or be age 7.

Cub Scout: must have completed 1st but not 3rd, or be 8 or 9.

Webelos Scout: Must have completed 3rd but not 5th, or be age 10 but not yet 11.5.

Clear as mud?

DS is in 4th grade (homeschooled) age 8. Right now he is a Cub Scout (Bear rank.)