"I imagine for spring through autumn the antlers are still covered with velvet. This velvet provides for the nutritional needs of a shrub that grows on the Sawsbuck. This shrub is no mere parasite on the Sawsbuck however, it provides important camouflage from the predators of the Sawsbuck such as Beartic and Liepard. The plant also injects sugars into the Sawsbuck's blood stream, providing an energy boost to the host. The shrub is an annual that goes through its whole life cycle in a single year. Through out the spring and summer the plant is healthy in the velvet. However as autumn approaches the velvet begins to die and the plant with it. In winter the velvet has sloughed off exposing the bare white bone underneath. Before dying the previous years shrub had deposited seeds at the base of the antlers, so when the antlers are shed at the end of winter the seeds grow on the velvet of the new antlers. The cycle begins again in the spring when the new antlers sport the newly sprouted seeds. First order of buisness is reproduction and as the Sawsbuck rutt to establish the hierarchy of the herd, the flowers are pollinated. This system provides for the welfare of both species." - Profesor Baobab.
I love the concept for Sawsbuck, as a deerling it's pelt changed when the seasons changed. As a Sawsbuck the antlers change the most to represent the seasons. I still have to evolve both my Deerlings.