The Story
Apologies, this story is more Attenborough than Melville
The Salish Sea is grand and dynamic. It has wide open straits, tight passes, deeply carved trenches and sloping shallow banks. Within every nook and cranny of this large inland sea there is life. These nutrient rich waters support a large diversity of invertebrates, fishes, and marine mammals as well as a few rapidly growing human metropolises. Every day we go out we have the opportunity to see seals, sea lions, and a large variety of cetaceans. The Salish Sea is connected to the wider Pacific Ocean through two points: The Strait of Juan de Fuca on the southern end and Johnstone Strait on the northern end. Through these gateways anything can come from the open ocean. Throughout the year we usually see the same characters arrive around the same time we see them every year. There are the two ecotypes of Orcas aka Killer Whales (Orcinus orca) that travel in and out of the sea year-round: the Southern Residents and the Transients. There are the Humpback Whales (Megaptera novangliae) and the Grey Whales (Eschrichtius robustus) that arrive in the spring. There are the Dall’s Porpoises (Phocoenoides dalli) and the Pacific White Sided Dolphins (Lagenorhynchus obliquidens) that we often see in the fall. And, of course, there are the Harbor Porpoises (Phocoena phocoena) and the Minke Whales (Balaenoptera acutorostrata) that stay year-round. Every so often either due to changing conditions in the North Pacific or just pure happenstance we run into strangers to these waters. In the past decades these strangers have actually just been whale populations returning to their old "stomping" grounds which had become dangerous in the hey-days of the western whaling fleets. Humpback Whales and Fin Whales both were gone for around a century and now we see many Humpbacks every year and in the past few years around twenty or so Fin Whales have visited the Salish Sea, but this story is not about them. A little over a week ago we saw something even stranger. As we were returning after watching J pod, part of the Southern Resident Orcas, in Boundary Pass a large whale surprised us by surfacing not too far in front of our bow. It surfaced in between us and Turn Point and exhaled a giant blow that shot into the air from a dark grey body that was definitely longer than M/V Sea Lion, our 55 ft. (17 m) - long vessel. This giant remained logging at the surface and continued to breathe deeply and release large blows, and our crew very quickly realized from this behemoth's appearance and leftward-slanted blows that this was a Sperm Whale (Physeter macrocephalus). This is very unusual for this area. Cetacean fans all over the Salish Sea had been tracking this male Sperm Whale as it journeyed from Johnstone Strait south along the British Columbia coast. The excitement was well-founded since, as far as I know, this is the furthest a Sperm Whale has made it into the Salish Sea ever.
Sperm Whales - Why they're far from normal close to home
Sperm Whales are a worldwide species that tend to concentrate in tropical and subtropical waters, but they prefer to feed in deep water usually off of continental shelves. Here some reports say they are diving to perhaps 3,000 feet (~900 m) to catch large squid and large fish in the dark depths. Here, the deepest depths around the San Juan Islands only reach around 1,000 feet (~300 m). The Salish Sea doesn’t provide the depths, habitat, nor the abundance of their preferred prey. As far as I know the schools of squid here maintain their body size to smaller than that of a dog unlike the sperm whale’s favorite and hardest won snack – the 43-foot (13 m) Giant Squid (Architeuthis dux), so even if there have been more previous visits they most likely were exploratory and brief. They might have munched on some large Halibut though... Lastly, if we did start seeing them more often here it most likely would continue to be lone males. Adult females group themselves up into familial pods with their young offspring and stay in tropical and subtropical waters. Adult males venture off and travel alone into temperate waters and will return to travel with pods of females in tropical waters to mate during spring and summer.
Sperm Whales - Strangely Similar
Although this was the first and only Sperm Whale I have ever seen in my life I think it is appropriate and definitely cool to compare them to our usual whales of interest – the orcas. First off Sperm Whales are also large toothed whales just like orcas. They are not super closely related since orcas are dolphins within the family Delphinoidea along with most dolphins, porpoises, belugas, and narwhals, while Sperm Whales are located on the branch, Physeteroidea, but they are more closely related to each other than they are to Mysticetes, the baleen whales (like Humpback, Grey, and Blue Whales). Since they are booth toothed whales though, Odontocetes, they both hunt large prey, catch them using teeth, and often track their prey using echolocation. This ability to echolocate means that they can “see” using sound waves a little like using sonar on a boat or a submersible. Sound waves are sent out in audible clicks by manipulating “phonic lips” within their modified sinuses which bounce off anything in the water in front of them and return eventually to their inner ears and are interpreted into 3-dimensional information within their brains. That’s another similarity: both Sperm Whales and Orcas are incredibly intelligent! Sperm Whales actually have the largest brains in the world and both Orcas and Sperm Whales have a large brain to body size ratio akin to humans. Along with the clicks these whales use to “look” at their underwater world they also both use series of sounds to communicate to one another and each species has ways of identifying individuals within a larger group. Orcas, like their smaller dolphin cousins, have signature whistles (like names) that seem to be related to their mothers' signature whistles. Sperm Whales seem to use a series of clicks that we call codaclicks to identify themselves. The clicks are the same for all the sperm whales in a particular group or sometimes for all sperm whales worldwide, but each whale says it with its own “accent” to identify themselves. Pretty neat, huh? These two whale species also have similar familial structures especially if you compare the Transient (Bigg’s) Orcas that inhabit the west coast of North America and Sperm Whales. Sperm Whales, like orcas, form pods of related members. Pods in Sperm Whales usually consist of related adult females and their offspring. Adult males usually only join for mating season and often have to compete with other males to mate with a group of females. When it is not mating season, males will either go off to hunt on their own or if they are too old to be in a pod any more but too young to compete for mates they will form bachelor pods with other young males. Bigg’s Orcas similarly have pods organized by familial relation and led by females but in contrast, even adult males will stay with their mother’s pod for much of and sometimes their entire life. Even in these Bigg’s Orca pods, males sometimes do leave their mothers and will venture off alone or with other adult males and occasionally travel and hunt with other families in order to mate with their adult females. They will stay sometimes for months and then go off on their own again.
Final Thoughts
Like the smooth glassy water left by Yukusam as his massive tail disappeared below the surface, here are some thoughts I'll leave with you. Despite all the similarities between Sperm Whales and Orcas, Sperm Whales are very unique and still pretty mysterious. Since their main habitats are far offshore and their dives deep and can last from 35 to 90 minutes or longer, we see even less of their lives and activity than other whale species. These deep, prolonged dives could explain their odd body shape. At around 50 feet (15 m) in total length their enormous heads make up about a third of that. Their massive noggins contain a thick oily substance called spermaceti that could be used for buoyancy control or acoustic manipulation - humans are still unsure. Also contained in their large head space apart from their massive brains is the mystery of their blowholes. Like all whales they have two nares (tubes that connect to their windpipe) that approach the top of their head but one of the nares just stops before it reaches the top of their head. The left one though, does reach the top of their head. They breathe through this one thus showing a blow that slants to the left with each breath. Also, within those mysterious winding tubes in the Sperm Whale’s head lies their acoustic apparatus. With this they see their underwater world and are one of the loudest animals in the world. Sound leaving their heads can come out at around 230 decibels which cause shock waves that can stun their prey and if an unlucky human got in the way it could rupture their lungs. Pretty wild. Whale, that's all for now folks. We hope to see you all and of course another Sperm Whale real soon!
Naturalist Erick
Sources
http://www.marinemammalcenter.org/education/marine-mammal-information/cetaceans/sperm-whale.html
https://www.nytimes.com/interactive/2016/04/16/opinion/sunday/conversation-with-whales.html
https://www.livescience.com/14197-sperm-whale-language-accents.html
https://www.nationalgeographic.com/animals/mammals/s/sperm-whale/
http://blog.nwf.org/2016/07/7-facts-about-sperm-whales/
http://us.whales.org/species-guide/sperm-whale
http://tolweb.org/Cetacea/15977
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