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.
Regrettably, researchers say about 75% of newborns in the recent two decades following designation of the Southern Resident killer whale population as "endangered" have not survived, and 100% of the pregnancies in the past three years have failed to produce viable offspring.
The whales have been struggling because of a lack of salmon, and J35's calf died soon after birth on July 24.
Killer whales have been known to carry dead calves for a week, but scientists believe this mother "sets a record".
Balcomb said he also saw J50 with her mother and brother on Saturday, along with NOAA researchers who were following her to collect prey remains and feces.
"She is alive and well and at least over that part of her grief. It is no longer there", Ken Balcomb, founding director of the Center for Whale Research, told the Seattle Times.
Tahlequah is one of two orcas in the pod that scientists have been monitoring.
The mother whale - known as J35 - has captivated the world's attention in the past few days.
The centre says the carcass likely sank to the bottom of the Salish Sea, and researchers may not get a chance to perform a necropsy.
Both Canada and the United States list the Southern Resident killer whale as endangered.