(CNN) Two years ago, the world watched with a heavy heart as a mother orca carried along her dead newborn for more than two weeks. Now, that same orca is pregnant again.
Tahlequah, or J35, as she's known by researchers, isn't the only Southern Resident orca expecting.
According to drone photos, she's just one of several pregnant killer whales that have been identified by researchers since early July, according to SR3, a sea life response, rehab and research group.
In 2018, Tahlequah swam for 17 days with her dead newborn. Refusing to let it sink, she pushed her calf toward the surface of the Pacific off the coast of Canada and the Northwestern US.
The orca population is a large extended family made up of three social groups, called pods, and orcas from each pod are expecting, according to SR3. It's unclear just how many, though.
It's not unusual for females from all three pods to be expecting at the same time, but the group said the majority of recent pregnancies have not been successful.
"Studies by our colleagues at the University of Washington have shown that these reproductive failures are linked to nutrition and access to their Chinook salmon prey," the online release said. "So, we hope folks on the water can give the Southern Residents plenty of space to forage at this important time."
Space for these orcas to feed is crucial since the Southern Resident population is at a low of 73, according to the Center for Whale Research.
SR3 shared photos online of J35 and L72, another pregnant orca. The aerial images of both orcas show their body sizes in September, when they were several months into their pregnancies, and recently in July, with an increased width mid-body, revealing that they're in their final stages.
Typically, killer whales are pregnant for 17-18 months, according to SR3.