The grieving mother had been pushing her dead orca calf around the water for 17 days after giving birth near Victoria, British Columbia in Canada.
Scientists have also moved to save J-50, another whale in the endangered pod.
Exacerbating the problem is that orcas do not have babies often or in large numbers, and when they do, it is a long process.
CWR founder Ken Balcomb said he was immensely relieved to see J35 returning to typical behaviour.
The Center for Whale Research said Tahlequah "vigorously chased a school of salmon with her pod-mates" when researchers spotted her on Saturday (local time).
Her recovery is important - not just for her own health, but for the health of the rest of her pod. Unfortunately, the salmon has been in dramatic decline in recent years.
The Center for Whale Research in Washington state said the whales have been struggling due to lack of salmon, and J35's calf died after birth on July 24.
There are only 75 southern resident killer whales - a distinct population of orcas that live in the northeast Pacific - and the group has not produced a surviving calf since 2015, meaning that they are at risk of dying out as they pass breeding age.
Aside from the emotional impact, this behaviour can have physical consequences too, but new telephoto images taken by the Centre for Whale Research reveal Tahlequah appears to be in good physical condition, with no evidence of 'peanut head' skull deformations incurred by the relentless pushing and not enough food.
Jenny Atkinson, executive director of The Whale Museum, told Here & Now's Jeremy Hobson that Tahlequah's grieving period was unusually long.
August 11, 2018 J35 update: "The ordeal of J35 carrying her dead calf for at least seventeen days and 1,000 miles is..." But Tahlequah's baby was not stillborn.
"No one really knows why moms carry their calves to begin with", said Haulena from his home in Point Roberts, Wash.
But on Saturday experts confirmed she had dropped the calf.
"It is a grief, a genuine mourning", he said. "Orcas. are charismatic megafauna", she said. Her podmates depend on it. "You're going to feel that pain of grief - particularly if you've gone through grief in your own life".