A pale whale was spotted among the 56 orcas seen swimming in the Salish Sea by naturalists over the weekend of April 3-4. The animal, named Tl'uk, is believed to be a rare example of leucism in killer whales, with a notably pale complexion compared to its black and white pod pals. Onlookers were also treated to another famous fin as Chainsaw, who has a distinctive notched dorsal fin, was also in attendance.
If the prospect of a white whale has you exclaiming “H’WHITE H’WHALE” then you’re not alone in appreciating the parallels to Moby Dick, even if that was technically a sperm whale (which really do ram boats like that, FYI). The book, however (inspired by the all-too-true and traumatic tale of the Essex), saw Captain Ahab and his whale-bone leg tracking down a whale that looked more like this humpback, which could be an albino.
The famous whale (yes, we know, orcas are dolphins) caught on camera in the Salish Sea last weekend is instead thought to be an example of leucism, a condition that gives rise to animals much paler than normal but that still have some pigment, as opposed to albinism, defined by a total lack of pigment. A similarly rare leucistic penguin was recently spotted in South Georgia, that had been treated to a rather funky yellow makeover as a result of their leucism. Tl’uk was named for the Coast Salish word for “moon” and is a familiar face to whale watchers in the area.
“He is definitely a unique whale and sightings of him and his family are very memorable,” Jeff Friedman of Maya’s Legacy Whale Watching in Friday Harbor, Washington, told IFLScience. “Sightings of Chainsaw are also memorable as he has such a unique and charismatic dorsal fin. They are both members of the thriving Bigg's (marine mammal-eating) killer whales we see often in the Salish Sea.”
Leucism and melanism – a condition which gives rise to highly-pigmented, often totally black animals – aren’t thought to be a clear indicator of poor health in the animal, but studies have found unusual patterns are sometimes linked to inbreeding and low reproductive success. While variations in coat patterns may not directly negatively impact the health of these animals, standing out from the crowd can be problematic for wild animals in hindering their chances of being selected as a mate. Sexual selection favors animals with the “healthiest” coats, and changes to the orca blueprint may be interpreted as a sign of dodgy genes.
The condition may or may not throw into question the reproductive success of Tl’uk, but fortunately for the species as a whole, things are looking up. “Their population has been growing over 4% each year since 2012 and we continue to see healthy new offspring each year,” explained Friedman. “Because we know so much about the family relationships and life histories of these whales, each encounter is a memorable and a great opportunity to share education and conservation information with our guests.”