The Center for Whale Research in Washington state says it watched the orca, known as Tahlequah or J35, chase a school of salmon in Haro Strait west of San Juan Island on Saturday afternoon.
"Her tour of grief is now over and her behavior is remarkably frisky".
She finally abandoned the carcass as it decomposed, the AP reports.
Tahlequah captured nationwide attention after being spotted carrying her dead calf, which died about a half hour after being born on July 24, the National Oceanic and Atmospheric Administration said.
"The baby's carcass was sinking and being repeatedly retrieved by the mother, who was supporting it on her forehead and pushing it in choppy seas", the CWR said in a statement at the time.
"We've had a number of dead babies that get carried for part of a day, but nothing like this", said Ken Balcomb, a founder and scientist at the centre.
Researchers had anxious J35, who was last spotted with her dead calf Wednesday, was not eating properly and was spending too much energy pushing the corpse.
Scientists have also moved to save J-50, another whale in the endangered pod. Most killer whales eat a wider diet, but this particular group of about 75 resident orcas eats just salmon, which have been overfished in the area for commercial consumption. "Telephoto digital images taken from shore show that this mother whale appears to be in good physical condition", says the Centre for Whale Research. The CWR says 100% of pregnancies for Southern Resident killer whales over the past 3 years have failed to produce viable offspring.
The young, malnourished animal was given a shot of antibiotics earlier this week in hopes of helping it fight an infection.