Blue Whale

Balaenoptera Musculus


90-100 feet (27-30 m) in Southern Hemisphere
75-80 feet (23-24.5 m) in Northern Hemisphere


100-150 tons (100,000-136,000 kg)


Found in all oceans, they migrate to tropical waters during winter months to mate and give birth.


Endangered – 3,000-4,000 in N. Hemisphere; 5,000-10,000 in S. Hemisphere


The blue whale is the largest mammal, and possibly the largest animal, to ever live on earth.  The blue whale is a baleen whale and belongs to a group of whales known as the rorquals, which also includes humpback whales, fin whales, Bryde’s whales, sei whales, and minke whales.  These whales have throat grooves that expand while the animal is feeding.  Blue-gray in color, the blue whale is long and slender with a small dorsal fin located three-fourths of the way down its back.

Blue whales feed almost exclusively on small shrimp-like creatures called krill which get stuck in their baleen plates and can eat up to 40 million krill each day.  They can be found alone or in small groups, but it’s most common to see blue whale in pairs.  They can reach speeds of 30 miles per hour (mph) if alarmed, but usually travel around 12 mph.

It is believed that the population of blue whales was once more than 350,000.  Unfortunately due to the whaling industry, 99% of the population was killed, with now just 8,000-14,000 whales remaining.  Fortunately it is no longer permitted to hunt whales of any kind, but numbers have been slow to recover.