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Blue Whale (Balaenoptera musculus)
Two weeks ago, Ferrebeekeeper presented a post about the smallest known mammal, the Etruscan shrew. Today we head to the opposite extreme: the blue whale (Balaenoptera musculus) is not merely the largest known living mammal, it is the largest animal of any sort known to have ever existed. The greatest dinosaurs, the colossal squid, and the most immense pliosaurs were pipsqueaks compared to the blue whale. The giant cetacean has been measured at lengths of 30 metres (98 ft). A single whale can weigh up to 180,000 kilograms (200 tons) which is about the weight of forty African elephants (or approximately one hundred million Etruscan shrews). Superlatives stop making sense when describing the blue whale: a human could swim through its largest veins; a whale can eat 4 tons of krill a day; it can make a noise louder than a jet engine. When I worked for the Smithsonian Institution back in the nineties, it was said that the longest object in the collection was the life-size blue whale model. It wasn’t until the Air & Space museum acquired a space shuttle that the Washington museums got something bigger (although maybe that’s because they decided not to assemble their Saturn V). If you want a true sense of the size of Balaenoptera musculus, here is a life size poster of one on the internet (be forewarned: unless your monitor is the size of a drive-in theater, you are just going to be scrolling hopelessly around an endless wall of blue-gray).
Although there are different groups which have slightly different physical characteristics, blue whales can be found in all of the deep oceans of the world (with the exceptions of Europe’s seas, the great gulfs of the Middle East, and the Arctic Ocean). I would like to tell you more about the lifespan, breeding habits, vocalizations, and social life of the blue whale, but, incredibly, very little is known about these aspects of the creatures. Scientists speculate that blue whales live to be about 80 years old (or possibly older), but they don’t know for sure. How whales choose mates is unknown (although it presumably involves the remarkable range of noises which they make). Gestation lasts anywhere from 10 to 12 months.
Blue Whale Mother and Calf from Amos Photography
Once baby blue whales are born they grow fast! Blue whale calves can put on 4 kilograms (9 pounds) an hour. Adults are masters of the deep: fully grown blue whales can dive for up to half an hour to depths of 500 meters 1,640 feet. They have two blow holes behind a streamlined spray guard. Like the other mysticeti, blue whales are filter feeders. They take huge amounts of water and krill into their mouths and then push the water out through long baleen plates. When adults fully open their mouths the area is equivalent to the volume of a boxcar!
Blue whales are capable of traveling 50 kilometres per hour (31 mph) over short bursts, so back in the days of sail, a blue whale encountering a ship would simply swim away. Only when humankind began to make modern ships powered by fossil fuels could we keep up with the gentle giants. Alas for the whales–we learned to build such ships (and explosively propelled harpoons) and soon we were killing the creatures by the hundreds of thousands so that they could be rendered into oil. Between the 1880s (when the whales first began to be hunted en masse) and the 1920s the whales’ population declined from 350,000 to perhaps a thousand. All nations stopped hunting the whales in the early 1970s. In less than a hundred years, humans almost eradicated the largest animal ever known…yet, in the end we have not yet wiped out the blue whales. They are still here. As you read this, there is a creature the size of a space shuttle eating millions of krill somewhere in the vasty oceans.
A diver with an immature blue whale
A Crabeater Seal on an Iceberg (photo by Rob Wilson)
The crabeater seal (Lobodon carcinophagus) is a pale-colored seal which lives on the pack ice around Antarctica. Adult crabeater seals have an average length of 2.3 meters (7 and-a-half feet) and weigh around 200 kg (440 pounds) however the largest male crabeater seals can weigh up to 300 kg (660 lb). The seals’ mass alters considerably over the course of a season as they gorge themselves in preparation for lean times (or—in the case of mothers—for nursing). Like other Antarctica seals, crabeater seals have slender bodies and long snouts. They are gifted swimmers—a talent which allows them to escape their two main predators, killer whales and leopard seals. They infrequently venture beyond the continental shelves of Antarctica (although very rarely one is spotted at New Zealand, Patagonia, or South Africa). They hunt along the pack ice and travel far inland to give birth. The seals give birth to one pup annually and they can live up to 40 years.
A Crabeater Seal (Lobodon carcinophagus)
Crabeater seals can slither over land fairly well and they range farther onto continental Antarctica than any other indigenous mammal. Crabeater seal carcasses have been found up to 100 kilometers from the coast. So crabeater seals have whole swaths Antarctica to themselves (well aside from big weird penguins, lichens, and Norwegian explorers). Although they may theoretically eat a crab every now and then, the seals are misnamed. Their main prey is Antarctic krill, which they eat in huge quantities (as an aside, Antarctic krill is believed to have the greatest biomass of any single species on Earth). Although they do not have baleen like the great rorquals, crabeater seals have specialized krill-filtering cusps on their teeth which trap the krill and allow water to escape. When krill are not available, the seals can also feed on fish and squid.
Crabeater Seal Teeth
Perhaps the most remarkable thing about crabeater seals is their sheer numbers. Other than humans (and our livestock) they are the most numerous large mammals on the planet. Caribou and wildebeests exist in herds of hundreds of thousands, but the crabeater seal population numbers in the millions. The full population of crabeater seals is unknown. Estimates range from 7 million to 70 million. Since they are pale colored seals darting between the crushing pack ice of an uninhabited continent we have a population estimate which is off by a factor of ten. The fact that so few people have seen them might explain why they are still so successful.
A Crabeater Seal enjoys sunbathing on a southern beach.
Antarctica Seen from Space
Imagine standing high above planet Earth and looking down at the blue and white band of seas surrounding Antarctica. You are looking at one of the most important features of the Earth’s surface. The turning of the planet and strong westerly winds drive the cold deep waters of the Southern Ocean into the planet’s largest and most powerful current system, the Antarctic Circumpolar Current (ACC). The clockwise current isolates the frozen continent into its own self-replicating climate. Since there are no great land masses lying in the ring of open water at these latitudes, the ACC also forces waters from the ocean depths up to the surface. This upwelling brings rich nutrients from the depths and causes immense blooms of phytoplankton (which in turn nurture life throughout all the world-ocean). Additionally the current stirs the circulation of the Atlantic, Pacific, and Indian Oceans.
The ACC has been known to sailors for centuries. A sailing ship can travel west along the current with great speed (if the sailors have the bravery and stamina to confront the fierce winds of “the roaring forties”). The “clipper route” was the fastest sailing route around the world, but it was dangerous. The three great capes (Cape Horn, the Cape of Good Hope, and Cape Leeuwin) all claimed innumerable lives as did wind, ice, and storm. Today the clipper route has been abandoned as self-powered ships bring their cargoes of plastic junk straight across the ocean from China (and then cut across the Panama Canal) but sailing enthusiasts still recognize the fastest way to ride the wind around the planet. The major circumnavigation sailboat races all travel the clipper route.
“Roaring Forties” (Gordon Frickers, oil on canvas)
The true history and significance of the ACC vastly exceeds the paltry recent concerns of navigation and world trade. Geologists estimate that the ACC current began spinning around 34 million years ago at the end of the Eocene epoch as Antarctica split from Australia and drifted further south. Back when Antarctica and Australia were still connected, the great amalgamated continent was a place where cold southern water and chill weather mixed together with tropical warmth—thus causing the whole planet to warm up. However when Antarctica broke away and drifted south, it started a series of climate feedback loops. The oceans around the continent began to freeze and ice started to build up on the mountains. An entire continental ecosystem began to change in the cold. The tropical forests (which had been filled with strange marsupials) began to die and become tundra. As the Oligocene progressed and Drake’s Passage widened, the rivers–once filled with catfish–turned to ice. The landmasses of Antarctica became crushed down under immense glaciers. Antarctica died in the cold. By 15 million years ago it became as it is now–home to only tardigrades, lichen, and a handful of visiting birds and seals.
The Transantarctic Mountains (photo by John Goodge)
Even now the Antarctic Circumpolar Current still isolates the continent from the warmth of the rest of the world. Yet through upwelling of iron and other nutrients, the current bolsters an immense fecundity of phytoplankton–the great primary producer of the ocean. Masses of copepods and krill feed on the algae and the diatoms and they in turn are eaten by fish, mollusks, mammals, birds, filter feeders…everything. The great southern oceans are among the most diverse and strange habitats for living things. It is there that the largest mollusk on the planet is found—which is the subject of an upcoming post.
The largest animal to ever exist is the blue whale (Balaenoptera musculus) an immense rorqual capable of growing to over 30 metres (100 ft) in length and 180 metric tons (200 tons) in mass. Although science has made substantial progress in understanding these great leviathans, the whales still harbor many secrets. However today’s post is not meant to be an overarching description of the giant mysterious creatures.
Image: National Geographic Channel ’s Kingdom of Blue Whale
Nor is this tiny post a comprehensive history. The blue whales have a story as big and long as they are, but, so far it has been a sad tale. Once their population numbered in the hundreds of thousands, however steel boats, exploding harpoons, and humankind’s inexorable appetite quickly winnowed them down to a few hundred in the 1970s. Today the blue whale population is estimated to number one percent of what it once was—and, although the population is slowly growing, the blue whales face competition for food (krill is industrially harvested as food for fish farms), changing global ocean currents, and death or serious bodily injury from shipping. A big container ship can kill a blue whale like an SUV crushing a toddler.
To sustain their immense bulk, blue whales must eat a prodigious amount of krill. A hungry adult whale can eat up to forty million of the tiny crustaceans per day (along with whatever copepods, squid, and fish are accidentally caught up along with the krill). The whales follow the huge pink underwater clouds of krill as they drift and twist through the oceans and thus circumstance (or crustacean whim) occasionally puts the blue giants in proximity to humans. When this happens the whales are a source of great wonder, but they are also in terrible danger from shipping.
Blue Whale Feeding on Krill Near the Surface (Barbara Howard, Acrylic on Canvas)
This is what is happening right now off Long Beach, California (the port complex of Los Angeles) which is the busiest port in the United States. The largest concentration of blue whales along the North America coast has gathered outside the port along the continental divide in order to hunt for krill. Marine biologists have been monitoring the whales with suction-mounted radio trackers which fall off after one day. Not only can the biologists radio warnings to ships coming close to the blue whales, they are also able to analyze the cetaceans’ behavior in order to better prevent accidents.
On October 7th, The LA Times reported that, “An 80-foot whale whose tag was scooped from the ocean Tuesday is a regular visitor that has been in the area for about a month. When researchers tagged the same whale a week before, they downloaded data that revealed a typical behavior pattern. The animal spent most of the day just outside the port, diving as deep as 1,000 feet. After dark, it stayed near the surface, perhaps to rest, and swam to the Santa Monica Bay.”
Lingering near the surface of the water beside the country’s busiest port after dark is dangerous behavior even for an 80 foot sea monster! Listen whales, everybody loves all-you-can-eat shrimp buffets (and everybody really loves to see blue whales) but you guys need to get out of LA. Take a clue from the fate of all the innocent teens hoping to break into the movie industry and move along before you get hurt. Blue whales can live to be 110 years old if they aren’t run over by ships filled with plastic crap from China!
Of course if you don’t think the whales will listen to my blog, it might be worth contacting your political leaders and asking for more comprehensive protection for ocean life.
ferrebeekeeper 