Answer:
Young males are always pushed out often with the brothers of their birth pride upon reaching or nearing maturity. This helps to increase genetic diversity among lions and prevents inbreeding depression. This pressure can come from blood relatives, but invading males will also kill or push all cubs out of the pride when they take over. Additionally, females who refuse male breeding attempts may be killed or banished. Among the males of pride who are often brothers, the largest male is the dominant one. Typically, the largest males have the largest and bulkiest manes, which help deter aggressors.
Hope this helps, have a nice day/night! :D
