As we go upstairs we arrive into the Cetaceans Gallery which hosts the spectacular collection of present cetaceans skeletons. This collection, one of the most important in Europe, was set by Sebastiano Richiardi during his direction (1871-1891), even though written documents testify that in 1626 some cetaceans finds were already in the Museum. In all, the Museum possesses 53 skeletons, 23 of which are here exposed.

Cetaceans are Mammals which got adapted to water life: they are almost hairless, and they have a thick adipose tissue; they have a hydrodynamic shape, with a partial or complete fusion of the seven cervical vertebra, forelimbs turned into flippers, tail turned into a horizontal fluke and absent hindlimbs; they have nearly lost their sense of smell so their nostril situated on top of their heads (and called blowhole) are for breathing use only. They are divided into two groups: Odontoceti (Cetaceans provided with teeth) and Mysticeti (Cetaceans without teeth).

The first part of the Gallery is devoted to the Odontoceti.

The biggest family is the Delphinidae one, of which we have here the common dolphin, the bottle-nose, the cow-fish, the killer whale, the false killer whale (cranium only), the lagenhoryncus and the pilot whale.

Among the Odontoceti we also find the porpoise and the neo-porpoise (Phocaenidae); the Gange river dolphin (Platanistidae), characterized by non-functional eyes covered in skin and completely moving cervical vertebra; the plata dolphin (Pontoporiidae); the sperm whale (Physiteridae), which is the largest odontocetus; the narwhal (Monodontidae), which male has a long and slender left incisor; the mesoplodont whale and the bottlenose (Ziphiidae).

The second part of the Gallery is devoted to the Mysticeti, characterized by the absence of teeth, which have been replaced by whalebones, that is keratin brushes coming from the palate to the mandible and allowing a filter-feeding. You can see the whalebones of a newborn whale and several skeletons, of North Atlantic right whale (Balenidae), humpback whale, minke whale, rorqual whale and blue whale (Balenopteroydae). Being 30 meters long, the blue whale is the largest living animal: the specimen here exposed is about 24 meters long.