Cub Scouting is a program of the Boy Scouts of America to encourage growth and development of boys who are not yet old enough to be Boy Scouts. Cub Scouts range in grade level from first to fifth grade. Cub Scout units are referred to as "packs" rather than "troops", and packs subdivide further into groups known as "dens" often led by "den mothers". Cub scouts move into a new rank for every year of the Cub Scouting experience one is involved in, according to the following designations: Tiger Cub, Bobcat, Wolf, Bear and in the fourth and fifth grade Cub Scouts are called "Webelos",  One of the main goals of the Webelos program is to transition boys from Cub Scouting to Boy Scouting. The highest award that a Cub Scout can earn is the Arrow of Light Award, which is also the only Scouting award that can remain on a Boy Scout's uniform from his Cub Scouting days.