Conversation so far:
Who did Gary Cooper become friends with?
Gary Cooper became friends with Ernest Hemingway.
How did Gary Cooper become friends with Ernest Hemingway?
Gary Cooper and Ernest Hemingway shared a passion for the outdoors and often went hunting together.
Where did Gary Cooper and Ernest Hemingway meet?
Gary Cooper and Ernest Hemingway met in Sun Valley, Idaho in 1940.
What were some of Gary Cooper's interests?
Gary Cooper's social life generally centered on sports, outdoor activities, and dinner parties with his family and friends from the film industry.
Did Gary Cooper have any other interests besides sports, outdoor activities, and dinner parties?
Gary Cooper enjoyed riding, fishing, skiing, and later in life, scuba diving.

Question: What else did he do in his free time?
Self-contained rewrite: What else did Gary Cooper do with free time besides sports, outdoor activities, dinner parties, riding, fishing, skiing, and scuba diving?