By Mera McGrew
Blue whales, which are listed as endangered on the International Conservation Union (IUCN) Red List, are the gentle giants of the ocean.
Scientifically knows as Balaenoptera musculus, they are the largest animals known to have ever lived on Earth. At birth, a calf can measure about 23 feet (7 meters) in length. Fully grown, they can reach up to 108 feet (33 meters) and weigh upwards of 200 tons (181 metric tons). Reaching sizes comparable to a Boeing 737—and with hearts that weigh as much as a Volkswagen Beetle—the blue whale is even larger than the biggest dinosaurs that roamed the Earth during the Mesozoic and Paleozoic eras.
These giant marine mammals reach such massive sizes by eating tiny shrimp-like animals known as krill (euphausiids).…