The energy expenditure of chasing and fighting during the breeding season can result in a buck losing an immense amount of weight, with some research documenting losses of as much as 20% of body weight. On average, a buck before breeding season can weigh up to . After he has gone through the stages of rut, he can lose about of weight, which is quite large, especially for only a few months of time. In the post-rut, a buck will need to replenish his body and catch up on the weight and energy he has lost.