On Being Big

One of the inspiring features of biology is the huge variety that life forms come in. Here is the recipe for an impressive range of biological form and function. Mix together the correct chemical and environmental conditions for life, create regular challenges for feeding and reproduction then stir the soup for a few billion years. Voila, the planet is covered inside and out, high and low with more species than we can describe or count. Natural history museums, which include zoos and aquariums, show us the full range of forms and functions, and how it makes a living in the real world.

Some life forms are so big that they cannot easily be shown in a museum. Dinosaurs have been assembled all over the place, and killer whales and belugas are swimming in pools, and those are impressive. But let’s talk about the biggest animals to ever live on Earth…and that still live on Earth. How about Balaenoptera musculus, the blue whale? This creature is so big that even when you see a model it is awe inspiring.

Blue Whale Skeleton - Martin Lipman, CMN

Blue Whale Skeleton - Martin Lipman, CMN

Just how big is big? A fully grown adult blue whale is 180,000 kg. A number too big to mean anything, unless you know it equals the weight of two 767 air planes…without the passengers! These creatures prefer to eat crustaceans the size of your thumb (krill), to the tune of 3,000 kg – 7,000 kg / day, or the same weight as 2 – 4 Volkswagen Beetles. When they finish eating for the day, these predators have consumed over 1,000,000 animals. The blue whale is so big that when it decides to use its voice it can project it up to 1600 km under water. Their voice is important because they like to swim alone, in all the oceans, so need a powerful noise maker when they want company. Embryonic whales are so big that they take about a year to form and then are born as an 8 m long whale. These calves grow rapidly on a milk diet, high in fat. They drink 400 L of milk / day, gaining 91 kg / day for the first year. They add on the weight of an NHL hockey player each day. Keeping on the hockey theme, if an adult blue whale wriggled onto an NHL ice rink and put its tail on the centre line, its nose would stretch to the back of the goal, or about 30 m. To give a final perspective on big is the size of that impressive mouth. Considering the volume of water used during the average Canadian shower, you would need to keep the tap on for 3.5 days to fill up a blue whale’s mouth. That is big.

But being big is not always an advantage, especially if you are being hunted. Blue whales have natural predators (killer whales), but these are nowhere as dangerous as human hunters, who for decades took thousands of whales each year, especially with advanced technology for capture and transport. Scientists estimate that 10,000 to 25,000 blue whales still exist, which means this species is in danger of extinction.

To see a real blue whale (skeleton) you can visit the Canadian Museum of Nature. It is the remains of a juvenile (20 m in length) that washed ashore in Codroy, Newfoundland in 1975. Following a train ride to Ottawa, 10 years under-ground, a high-tech enzyme bath and the engineering feat of assembly, there is a blue whale in the new RBC Blue Water Gallery. By studying and learning from the largest animals on Earth we can better understand our limits and our relationship with other small players in the natural environment.

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