Earth Mother is a woman who left her tribe after her husband passed away. She found a clearing and cave to live in and spent her days looking after wounded animals whom she came to love and regard as her children.
When Yakari and Buffalo Seed came to her home, she hid, and later that night frightened them off, pretending to be the Moon Spirit. They spent another night and this time caught her in a net, but quickly released her once they saw she was an old woman. She explained her story to them but asked them to leave and promise never to tell anyone about her or her home. But when they left, Earth Mother fell ill when she broke her leg and her animals besought Yakari's help. He sent Buffalo Seed to get their medicine man and convinced Earth Mother to come to their tribe to be healed.
After spending time with the Sioux, she decided to allow them to live in her clearing and cave for the winters, having come to appreciate them for their kindness.
- In her next appearance, she was called Moon Spirit instead.