The diet of the cetaceans is very heterogenous, but characterized from a common element, in fact it is always constituted with animal organisms, even if of several dimensions, and it differs above all between misticeti and odontoceti.  

The techniques of hunting adopted by the cetaceans are several and have been adapted perfectly to the type of prechoice prey.

ANIMALS OF THE PLANCTON =  Small animals of several kinds and species long few millimeters transported for more by the currents (the Copepodi crustaceans).

KRILL = It's the word that identifies the small shrimp that lives in large branches whose varied composition change in the marine ecosystem in which they lives, turning out constituted in greater or minor amount from Eufausidi (small shrimp that do not exceed 6 cm of length, with a transparent body presents with various species in all the oceans) fit for a good mobility. The Krill also being composed of different organisms is behaved like an only great compact and concentrated organism remaining in determined zones and completing every day vertical migrations from the bottom to the surface and vice versa; it has moreover the ability to multiply very quickly (every individual can place also 20.000 eggs) and eats in its turn of microscopical animals or algae sayings fitoplancton.  

MISIDACEI = Crustaceans similar to shrimp from the laterally lengthened and compressed body, whose dimensions vary from the 5 millimeters to the 18 centimeters.

ANFIPODI = Small crustaceans whose dimensions vary from little millimeters to 2 centimeters.

FISH = The preferred fish of the misticeti are those with bony skeleton (Teleostei) like the blue fish or the Gadoidei like the cods.

CEFALOPODI = Mollusc very developed, subdivided in approximately 1000 species, that live in all the oceanic ambient from the surface until to great depths, and are on the bottom (es. octopus and small cuttlefishes) and in open sea (es. squids).   

The great ductility of a nutriment system based on the set of teeth offers to odontoceti enormous varieties of possible preys therefore we can only give a short example.

FISH = The odontoceti feed themselves of nectonic fish (that lives in open sea), than benthic (that they live in proximity of the bottom).  

CEFALOPODI = See up

CROSTACEI = The crustaceans of which the odontoceti can occasionally be nourished have very greater dimensions of those own ones of the diet of the misticeti.

OTHER PREDE : BIVALVI, TUNICATI, POLICHETI, ALGHE, PINGUINI, TURTLES, PINNIPEDI, DELFINIDI. 

The killer whale is perhaps the deadliest predator of the seas, a big number of preys and also some species of sharks. Also in sweet water ambient like the rivers, some cetaceans like the Platanistidi (family of dolphins), have perfectly adapted feeding themself of fish which the siluridi. In a pair of circumstances have been demonstrated cases of cannibalism in the Killer whales, inside of two exemplary have been recovered in fact puppies of the same species.

Anche in ambienti di acqua dolce come i fiumi, alcuni cetacei come i Platanistidi (famiglia di delfini), si sono perfettamente adattati cibandosi di pesci quali i siluridi.

In un paio di circostanze sono stati dimostrati casi di cannibalismo nelle Orche, all'interno di due esemplari sono stati infatti rinvenuti piccoli della stessa specie.