Antlerz is made from a natural material that is rich in minerals: Deer Antlers! Wild deer shed their antlers once a year as part of a natural process, after which the deer re-grow another set. These shed antlers are gathered by ranch workers and transported to a manufacturing facility. The antlers are cut to the appropriate size, cleaned and packed. A mineral analysis of Antlerz show high concentrations of calcium and phosphorus, with trace amounts of iron, zinc,and sodium. These are great for your squirrels to chew on.