What is a Challenge, you ask?
A Challenge is the opportunity for any Wolfrider to battle a current Sergeant or for any Wolf to fight a current Alpha for the rank!

A Beta Challenge is a battle between a Sergeant and a Private, which must be approved by the Captain. The Private can challenge a specific Sergeant out of the two, but the Captain can choose to set up the Challenge with the other Sergeant. In a Challenge, the Sergeant and his wolf are fighting against the challenger and his wolf in a one-on-one battle (wolfrider to wolfrider), using practice firearms such as paintball rifles. The Challenge battle runs for 30 minutes in a part of the valley's tree-covered fields near the Fort - but if a rider is thrown off his wolf before time runs out, that pair is automatically defeated. Otherwise, at the end of 30 minutes, the pair with the most hit points is considered the winner of the Challenge and thus, the Sergeant.

An Alpha Challenge is a fight for dominance between two wolves, the Alpha versus a Gamma or even a Beta. Wolves rarely challenge the dominant Alpha as he has already proven himself to be the strongest and smartest of the pack, capable of constantly asserting his dominance over the other wolves. Challenges against the submissive Alpha is the usual case and must be a battle between same gender wolves since the Alpha pair is always mated - in other words, if the submissive Alpha is a female, than only a female wolf can challenge. But Challenges against a submissive Alpha have to unofficially be approved by the dominant Alpha since he is the one who chooses who to mate with and his mate is automatically the submissve Alpha. If the dominant has no interest in the challenger, he can interfere and force the challenger to back down; if he sees the challenger as a potential mate, he allows the two to fight and the winner is his mate as the submissive Alpha.