Too fast for early whalers, the blue whale remained out of reach until the invention of the rocket-propelled harpoon in 1855.
It wasn't until the turn of the 20th century however, and the start of industrial whaling, that they were taken in large numbers. At this time, some 239,000 blues lived in Antarctica, their stronghold. When the last blue was shot by commercial whalers in March 1973, only 360 remained there.
The Antarctic blue whale population has since crept to a little over 2,200 individuals, with the total world population estimated at between 5,000 and 12,000. Listed as "Endangered," the blue whale is no longer actively hunted — even for scientific reasons — but it does face other pressures including collisions with ocean vessels; entanglement in fishing gear; ocean noise that drowns out its vocalizations, making it impossible to communicate; and pollution.
What's a Blue Whale?
Blue whales take the prize when it comes to size. They are the largest animal on record, larger even than the most massive dinosaurs. To put the size of blue whales in perspective, an average blue whale is roughly the equivalent of 25 fully grown African bull elephants. A blue whale heart, alone, weighs one ton and the massive tongue weighs up to 5 tons. In measurements of length or weight, the blue whale has no equal.
The blue whale, like most rorquals, has longitudinal pleats that enable its throat to expand and intake huge gulps of food-packed water. These enormous gulps of fish, krill and plankton-filled seawater are essential, considering an adult blue whale must consume approximately 4 percent of its weight during the height of the feeding season in Antarctica.
The pygmy blue whale is a recognized subspecies, which is found in the Southern Hemisphere and northern Indian Ocean. Measuring nearly 80 feet, this whale is only a "pygmy" compared to its enormous cousins. The Antarctic blue whale subspecies is the largest of the three.
Blue whales are usually sighted alone or in pairs, although they have been known to form loose groupings around feeding grounds. They breach only occasionally, but they blow frequently (every 10 to 20 seconds for up to 6 minutes) — a powerful, column-like stream that can reach nearly 40 feet in the air. Blue whales are also notoriously noisy. They make extremely deep sounds that have been recorded at 188 decibels, which is the loudest recorded sound made by an animal. The sound of blue whales can be heard from 500 miles away, assuming you can hear such a low frequency.