Blue Whale * Blouwalvis * Balaenoptera Musculus

By NOAA Photo Library - anim1754, Public Domain,
It is the largest animal known to have ever existed, measuring a maximum confirmed length of 29.9 meters (98 feet) and weighing up to 199 tonnes (196 long tons; 219 short tons). That is equivalent to the wieght of about 30 elephants!. Blue whales live around 80–90 years or more.

Generally speaking, blue whale populations move between their winter breeding grounds near the tropics and their summer feeding sites close to the poles. Up until the end of the 19th century, blue whales could be found in large numbers in almost all of the world's oceans. It was almost completely eradicated by whaling.

The orca is the only known blue whale natural predator. As of 2018, it was thought that there were between 5,000 and 15,000 mature blue whales worldwide. In contrast, in 1926 there were at least 140,000 mature blue whales.

In the early half of the 20th century, the Antarctic saw a particularly high level of whale harvesting, with 350,000–360,000 whales taken there. 

Blue whales are affected by rising underwater noise from humans. As part of oil and gas exploration, they could be subjected to noise from seismic surveys and commercial vessels.
Other Common Names
Blue Whale
Great Blue Whale
Great Northern Rorqual
Sibbald's Rorqual
Sulphur-bottom Whale
Sulphurbottom Whale