The blue whale (Balaenoptera musculus scientific name), better known as blue whale measures between 24 and 27 m in length andweighs between 100 and 120 t, although there are records of individuals over 30 m in length and over 170 tons of weight , which makes it the largest animal that exists today and also the largest thathas ever existed on Earth.
The blue whale has a long, lean body that looks thin in comparison to most squat constitution of other whales. The head is large(covering about a quarter of his body), flat and U-shaped ', with a ridge extending from the spiracles to the anterior face.
When it surfaces to breathe, get your back and blowhole out of the water to agreater extent than other large whales and fin whales or Fin. This feature can be used by observers to differentiate these species at sea. Blue whales typically live alone or in pairs, although you cansee groups of up to seven individuals, with large concentrations of food have been recorded up to 60 specimens collected in the same area
The blue whale is considered the largest animal that everexisted on Earth.
Blue whales feed almost exclusively on krill, but also ingest small amounts of copepods.
An adult can eat up to 40 million krill in a day.   The whales always feed in theareas with the highest concentration of krill and may consume during the peak power up to 4 tons of crustacean in a day, although there are reports of consumption up to 8 tons
Other animals thatmigrate
Birds are animals that usually travel longer distances in a migration.
• Fish such as herring, plaice and cod make annual migrations.
• Salmon breed in freshwater but migrate to sea to feed,spawn and grow. After several years, adults returning to spawn, often by the same rivers where they were born.
• The caribou and zebras migrate each year in large quantities through the open plains...