Mammals or animals (latin Mammalia) belong to the most progressive class of vertebral animals (humans belong here as well). They are earth animals belonging to the superior organisation. The most important attributes of progressivity are: evolved central nervous system, live birth (except for cloacal ones, who lay eggs), and thermoregulation. They cub evolved off-springs and feed them with mother’s milk. The oldest known fossils are 200 million years old (Jurassic period).

There are around 5400 species of mammals around the world, which are attributed to 29 flocks. In 2009 there were 8 flocks and 72 species of mammals in Lithuania according to the publication “The mammals of the world”.

Mammals are exposed in three halls. There are 114 horns with part of skull, 35 skulls, 23 horns, 24 head taxidermies, 5 horns with skull, 17 skins and 37 tusks exposed in hunting trophy hall. Skeletons and paleontological material are exposed in paleontological – osteological hall.

The major exposition hall of mammals consists of 353 taxidermies and 24 skulls. Exposition is allocated in systematic order. It is possible to discover mammals of impressive size and exotic appearance in this hall: as for example – giraffe (Giraffa camelopardalis), the fastest mammal – cheetah (Acinonyx jubatus), the largest predator -polar bear (Ursus maritimus), the one of the smallest ones – the Eurasian pygmy shrew (Sorex minutus), and others.

92 species of mammals, listed in IUCN Red List of Threatened Species are exposed in section of mammals (23 species out of them are listed in the Red List of Lithuania). The following exposed representatives from the Red List should be mentioned: cheetah (Acinonyx jubatus), The Siberian tiger (Panthera tigris altaica), polar bear (Ursus maritimus), snow leopard (Uncia uncia), the Bornean orangutan (Pongo pygmaeus), lynx (Felis lynx), otter (Lutra lutra), European bison (Bison bonasus), and others.