For more than 15 years, Noah's Ark Animal Sanctuary in Locust Grove, Georgia, has been home to an unlikely trio of best friends. Leo the lion, Shere Khan the tiger and Baloo the bear have been together ever since the animals were rescued from a drug baron's home in Atlanta.

Sadly, Leo underwent surgery in mid-August — after several weeks of being severely ill — and veterinarians discovered that more than 80 percent of his liver was full of tumors. Because of the findings, they decided to let the lion go.

"Both Baloo and Shere Khan were able say goodbye to their lion brother, and we will monitor them closely for any signs of stress or depression as they are grieving the loss of a family member as well," the sanctuary posted in a statement on Facebook.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

Leo, the lion of Noah's Ark, says goodbye
Leo the lion leaves behind his best buddies, a tiger and bear, at the Noah's Ark Animal Sanctuary in Georgia.