Blue whales are the largest animals ever known to have lived on Earth, at up to 29.9 meters (98 ft) in length and with a maximum recorded weight of 173 tonnes (190 short tons)
They occur in all oceans except the Arctic and enclosed seas.
Their colouring is more blue-grey than blue with light grey or yellow-white undersides.
A blue whale’s skin markings are unique, much like fingerprints
Blue whales have relatively small eyes and their eyesight is thought to be weak
They have a diet composed nearly exclusively of tiny shrimplike animals called krill. An adult blue whale can eat up to 40 million krill in a day
Blue whales are usually alone or in pairs, but occasionally swim in small groups
Populations migrate towards the poles, into cooler waters, in the summer to feed. They migrate back towards the equator, into warmer waters, in the winter to breed.
They communicate using low-frequency whistles or rumbling noises. All blue whale groups make calls at a fundamental frequency between 10 and 40 Hz. The loudest sustained noise from a blue whale was at 188 dB
Blue whales can reach speeds of 50 kilometres per hour (31 mph) over short bursts
They typically swim at a depth of about 13 meters (43 feet) when migrating
The average lifespan is estimated at around 80 to 90 years.