They have a pair of blowholes side by side and lack teeth; instead they have baleen plates which form a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. Predation of Belugas and Narwhals by Polar Bears in Nearshore Areas of the Canadian High Arctic" (PDF). Anthropogenic threats and conservation needs of blue whales, "Balaenoptera musculus indica", around Sri Lanka".

This milk contains high amounts of fat which is meant to hasten the development of blubber; it contains so much fat that it has the consistency of toothpaste.As well as this, the eyes of a whale are placed on the sides of its head, so their vision consists of two fields, rather than a binocular view like humans have. The neocortex of many species of whale is home to elongated spindle neurons that, prior to 2007, were known only in hominids. Australia/Indonesia population – Whales in this region appear to winter off Indonesia and migrate to their summer feeding grounds off the coast of Western Australia, with major concentrations at Perth Canyon and an area stretching from the Great Australian Bight and Bass Strait.

Mysticetes contain a proventriculus as an extension of the oesophagus; this contains stones that grind up food. Although whales are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres and migrate to the equator to give birth.Climate change is creating deserts and dead zones, and hunting is driving many species to the brink of extinction. Gestation may last 10–12 months with calves being 6–7 meters (20–23ft) long and weighing 2–3 metric tons (2. Though these creatures, such as Dimetrodon, looked like reptiles, they were actually the archaic precursors of mammals. Initially, moving organisms such as sharks and hagfish, scavenge the soft tissues at a rapid rate over a period of months, and as long as two years.

By the time the first mammals evolved 200 million years ago, however, dinosaurs were the dominant vertebrates. The whale pregnancy/ gestation period lasts longer than the typical 9 month gestation period for humans. Whales, dolphins, and porpoises of the eastern North Pacific and adjacent Arctic waters: A guide to their identification". Whale spindle neurons are found in areas of the brain that are homologous to where they are found in humans, suggesting that they perform a similar function.This began to change in the mid-19th century with the development of harpoons that can be shot as projectiles. They have large reserves of blubber, more so for toothed whales as they are higher up the food chain than baleen whales. The IWC has designated two whale sanctuaries: the Southern Ocean Whale Sanctuary, and the Indian Ocean Whale Sanctuary. They can consume 34,776–1,912,680 kilojoules (8,312–457,141kcal) from one mouthful of krill, which can provide up to 240 times more energy than used in a single lunge. In Antarctic waters, blue whales accumulate diatoms of the species Cocconeis ceticola and the genera Navicola, which are normally removed when the whales enter warmer waters.