Buck was taken out of exhibit for 3 weeks to recover from surgery to fix his eye sight.
Tuesday he was back doing what he loves, something called tail slapping.
"He was slapping the ground and acting all tough and it was really fun to see him act normal," said Assistant Curator, Lyn Myers.
Buck's surgery cost $8,000.
The money came from Measure Z tax dollars that voters passed in 2004 for zoo funding.
Soon Buck will be moved to the new Sea Lion Cove.
The $10.5 million exhibit will be done in September.