An incredibly rare white orca calf dubbed “Tl'uk” has been spotted off the coast of Washington State.
“The thing that everyone is talking about with Tl'uk is his color,” Erin Gless, a naturalist with Seattle-based Island Adventures Whale Watching, told IFLScience in an interview. “He’s obviously white, he doesn’t look like other orcas.”
Because of his unique coloring, Tl'uk is named for the moon in the local Salish indigenous language. The one-year-old calf was first seen last November. It's not clear why Tl'uk is so uniquely colored, but scientists are quick to note that he is not albino.
“He is just really, really, light but you can still see that he has an eyepatch like an orca. We’re not sure why he looks the way that he does,” said Gless, adding that Tl'uk’s unique coloring is likely due to a condition called leucism whereby an animal experiences a partial loss of pigmentation that causes white or pale coloring of the skin.
And though he’s not the first white-colored orca to have been born in the area, Gless says he is the only one to have survived this long. In this population of killer whales, there have been a handful of calves born with similar coloring, who have all died shortly after birth. But Tl'uk is doing well and even looks a bit big for his age.
“You could call him a bruiser,” laughed Gless, noting that the “spunky” calf is not alone. Earlier last month, marine scientists spotted another younger, healthy white calf in California waters. Initially, the team thought that the young whale was Tl'uk, but it turns out that the calf belongs to another orca pod identified as the CA216 family group. It could be that the two calves share a dad – orcas are known to range as far south as California – but Gless adds that without genetic testing, we can't know.
Tl'uk belongs to a local, thriving pod of orcas whose native waters extend from Washington State northward to Southeast Alaska. They share the same home as the declining Southern Resident Killer Whale (SKRW) group made famous last year when a grieving mother refused to let her dead calf go for nearly three weeks. In recent years, this well-known extended family of Pacific Northwest orcas has been slowly dying off, reaching an all-time population low last summer after failing to birth a calf for three years. Even though the family successfully birthed a baby girl last spring, the population still faces challenges from declining salmon stocks across the region while T'uk's pod is thriving.
Tl'uk’s population live in the exact waters as the SKRW group and experience the same exposure levels to toxins and vessels, but one is doing “really well” while the other is incrementally dying off. That’s because Tl'uk’s family feeds primarily off of marine mammals like sea lions and seals. On the other hand, the SKRW group only feed on salmon. There have been more babies born to the mammal-eating group than there are in the entire SKRW group. Just to compare, right now there are 73 SKRW and there have been nearly 90 babies born to the mammal-eating population since 2012, explained Gless. But it isn’t as simply as being hungry and looking for another food source
“On paper, they’re the same species. As of right now, all orcas over the world belong to Orcinus orca," said Gless. Though, current research indicates that there are four different "types" of orcas, one of which may even be its own species. "The truth is that when you look at their DNA, they are very different,” said Gless. “A lion that is hungry isn’t going to look to grass as a food source. Orcas just aren’t wired that way, either. There are physical differences between the two orca groups and they may even have different enzymes to digest different sorts of food.”
Because Orcas can live to nearly 100-years-old and salmon stocks in the Pacific Northwest have seen increasingly depleted numbers over the last half-century, Gless says orcas are seeing their food source decline in their own lifetime. It’s not just a numbers game, either. Fish are getting smaller as humans target larger individuals. With smaller fish in the sea, orcas are left to put much more effort into catching the same amount of food but not getting the same return on energy investment.