The whale "vigorously chased a school of salmon with her pod-mates in Haro Strait" off Canada's Vancouver Island, the Center for Whale Research said.
"Her tour of grief is now over and her behaviour is remarkably frisky."
Killer whales have been known to carry dead calves for a week, but scientists believe this mother "sets a record".
The mother whale - known as J35 - has captivated the world's attention in the past few days.
