[UPDATE: 13 Aug 2018] She has finally laid her dead calf to rest, after carrying it in the Pacific Ocean for at least 17 days, US media reported.
Tahlequah was spotted swimming without the body last Saturday (April 11).
"Her tour of grief is now over and her behaviour is remarkably frisky," said the Centre for Whale Research said in an update.
It's been over two weeks, but one grieving mother hasn't come to terms with her newborn's death.
Killer whale Tahlequah was first spotted carrying her daughter's body on her back near Vancouver Island on July 24.
The calf is believed to have died of malnutrition shortly after her birth.
"We've seen mother killer whales carry dead babies briefly, for parts of a day. We saw one a few years back for a couple days. But this sets a record," Centre for Whale Research senior scientist Ken Balcomb told the BBC.
Tahlequah is part of the Southern Resident population which NOAA Fisheries says is critically endangered. There are only 75 of them left, the lowest in three decades.
According to the National Geographic, female orcas give birth every three to 10 years after a 17-month pregnancy.
The pod's pregnancies haven't produced a viable offspring over the past three years, said the research centre.
This is likely due to a sharp decline in the killer whales' main food source - the Chinook salmon - as well as contamination of the waters that they live in.
Meanwhile, marine biologists are closely monitoring the condition of Scarlet, an ailing three-year-old orca from the same pod.