Whales milk is similar in constancy as toothpaste; it must be thick, or else it will dissipate into the surrounding water
Whales are generally classed as predators, but their food ranges from microscopic plankton to very large animals.
Toothed whales eat fish and squid, which they hunt by the use of echolocation. Killer whales sometimes eat other marine mammals, including whales.
Baleen whales, such as humpbacks and blues, mainly eat krill when feeding in the higher latitudes (such as the Southern Ocean). They imbibe enormous amounts of seawater, which they expel through their baleen plates; the krill is retained on the plates and then swallowed. Whales do not drink seawater but indirectly extract water from their food by metabolizing fat.
A 2010 study has considered whales to be a positive influence to the productivity of ocean fisheries, in what has been termed a “”whale pump.”” Whales carry nutrients, such as nitrogen, from the depths back to the surface. This functions as an upward biological pump, reversing the assumption of some scientists that whales accelerate the loss of nutrients to the bottom. They note that this nitrogen input in the Gulf of Maine is “”more than the input of all rivers combined””, some 23,000 metric tons each year.”