There are three species in the teriofauna historically non-characteristic of the site, i.e. acclimatized muskrat, american mink and racoon dog. At the same time since the reserve existance one species, i.e. european mink, have disappeared, and others, i.e. bison and red deer, have been reacclimatized.
The insectivorous order is represented by 9 species. Only Laxmann's shrew, even-toothed shrew, eurasian least shrew and Miller's water shrew occur solitary but the rest species, viz. shrew-mouse, lesser shrew, water shrew, eurasian hedgehog and common mole are common ones. All of them are night animals. The wing-nanded are not sufficiently studied in the reserve. Representatives of 9 species were found on its territory. Lesser noctule, northern bat and pond bat occur very rarely and are recorded into the national Red Data Book.
The double-toothed rodents are represented by two widely spread species, i.e. the mountain hare and the european hare. Representatives of the gnawing mammals consist of 19 species and are the most diverse. Mice are represented by 7 murine families with 6 hamster ones dominating among them.
Beaver, squirrel, forest dormice, yellow-necked, field and house mice, black rat, bank and East-european voles are abundant species among rodents. Garden dormice and loir, bush mice, harvest mice, and root vole sometimes occur.
The carnivorous are represented by 12 species. Bear, lynx, wolf, fox, marten, ermine, least weasel, polecat, otter and american mink are common species.
Among the even-toed animals wild boar (200-400 individuals), red deer (100-200) and elk (300-400) are regarded as characteristic species of the reserve. Roe deer occurs rarely in mixed forests near clearings and haying meadows.
Bisons appeared in 1967 in the reserve open-air cages, and in 1974 a small group of animals was released in the southern part of the reserve. Now there is a free-living herd of 36 bisons adapted to the region climate. The species are a representatives of the national Red Data Book.
The Reserve avifauna is mixed by origin, there are no endemic species in it. Breed-cross features are stipulated by the territory belonging to the forest landscape area, to the spruce-broad-leaved forest stripe inside it and to the Nothern zoogeographical region of the Republic, Bird species, belonging to different fauna types in accordance with the centres of their beginnings, are hardly occured within the region. The majority of bird species in the Reserve belong to the European (38%), the Siberian (12%) and the Arctic (7%) fauna types. The transpalearcts total 31%. Other fauna types are represented in the Reserve by the following ones: Holarctic - 4 species, Mediterranian - 7, Chinese - 3, Mongolian - 5, Mountain Asian - 1, Tibetan - 1, of vague origin - 4.
By the character of environmental links the Reserve avifauna consists of forest birds and waterfowl and, to some extent, of open-space birds and of birds residing near settlements.
Bird population of nature ecosystems depends, as a rule, on structural complexity of the biocenoses and total biological productivity. In the Berezinsky Reserve this appropriateness is observed as a general tendency of the quantitative characteristics of the bird population which decreases from the forest ecosystems to marshland, meadow and aquatic ones. In the marshland ecosystems the bird population distribution decreases from the eutrophic to the meso- and oligotrophic ones. The bird population of lakes is the smallest (22 - 96 individuals/ square km; here and further in the text for the early summer) and is the biggest in spruce dry land and marshy land forests, in black-alder woods, pine and spruce-pine dry land forests (647 - 695 individuals/ square km).
Early in summer the total bird biomass of nature biotopes ranges from 6 to 117 kg/ square km, the quantity of transformed energy - from 4 to 22 ths kcal/ day square km.The available data indicate that the territory of the Reserve is a model for protecting birds characteristic of the spruce-broad-leaved forests stripe in Europe, and reflect the nature peculiarities of the northern part of Belarus. This territory is unique owing to the fact that two thirds of rare and vanishing birds constituing the avifauna genofund in the Republic inhabit it.
Rana temporaria.. Body length of pubescent individuals is 50 - 80 mm, weight - 10 - 44 g. It prefers damp alder, birch and mixed woods, and reaches in number up to 1200 individuals per hectare. In spruce and pine woods its number is considerably lower - 10 - 30 individuals per hectare, maximum - 120. In bogs, transition mires and swamped meadows in the Serguch river, Lake Olshitsa and Lake Manets flood-lands it is almost absent (some 10 - 20 individuals per hectare), in the Berezina flood-land meadows its numbers reach 200 - 250 individuals per hectare.
Rana terrestris.. Body length 40 - 65 mm, weight 5 - 30 g. Inhabiting along side with R. temporaria various forest biotopes, it is less numerous everywhere: no more than 20 - 30 % of the total amphibia density. The largest density was recorded in damp alder woods (450 individuals per hectare). R. terrestris adapts itself to open biotopes rather than R.temporaria. Thus, its density in the flood-land meadows of Lake Olshitsa and Lake Manets totaled 175 - 270 individuals per hectare, in bogs 70 - 140, in marshlands - 300, in the Serguch river flood-lands - 40. However, in the Berezina flood-land meadows overgrown with shrubbery the species number decreases abruptly and totals no more than 10 individuals per hectare.
Bufo bufo.. Body length is 50 - 120 mm, weight - 12 - 150 g. Inhabits mainly damp alder woods, swamped meadows overgrown with shrubs, in lake, river and the Serguch Canal flood-lands, and in crop fields near settlements. In these places it numbers 15 - 40 individuals per hectare.
Bufo viridis.. Body length is 50 - 80 mm, weight - 12 - 50 g. Inhabits forest edges, clearings and crop fields near settlements.
Reptiles. Five reptile species have been found on the territory of the reserve: Sand lizard (Lacerta agilis), Viviparous lizard (L. vivipara), Anguine lizard (Anguis fragilis), Grass-snake (Natrix natrix) and Adder (Vipera berus). The two first species are distinctly dominant.
Lacerta agilis. Grown-up individuals have 58 - 92 mm long body, weight 8 - 25 g. Inhabit mainly well-sunlit and warmed places. Numbers from 10 to 100 individuals per hectare, sometimes up to 500.
Lacerta vivipara. Usually smaller than L. agilis. Body length 45 - 65 mm, weight 2-7 g. More frequently occurs in bogs, river and lake flood-lands, swamped places, in damp wood clearing and edges. Numbers 5 - 200 individuals per hectare.
Anguis fragilis. Body length 170 - 250 mm, weight 15 - 30 g. Inhabits different forest biotopes. Numbers up to 10 individuals per hectare.
Natrix natrix. Reaches 500 - 1000 mm length, 80 - 300 g weight. Occurs in damp forests, along river and lake banks. Numbers from 2-5 to 100 individuals per hectare.
Vipera berus. Body length 350 - 600 mm, weight 50 - 120 g. Occurs in bogs, forest highland places, borderinf with swamped plots. Numbers from 1-2 to 15 individuals per hectare.
The ichthyfauna is the most wide-spread in the Berezina river - 33 species, in Lake Palik - 30 and considerably less numerous in running lakes such as Olshitsa - 17, Plavno - 16, Manets and Domzheritskoye - 15 species.
Pike Esox lucius, roach Rutilus rutilus, ide Leuciscus idus, redeye Scardinius erythrophthalmus, carpbream Abramis brama, perch Perca fluviatilis and ruff Acerina cernua are the most abundant fish species in the water-bodies of the Reserve.
Tench Tinca tinca, verkhovka Leucaspius delineatus, silver bream Blicca bjoerkna, zope Abramis ballerus, crucian carp Carassius carassius, groundling Nemachilus barbatulus and loach Misgurnus fossilis are common for every large water-body of the Reserve.
Nase Chondrostoma nasus, bitterling Rhodeus sericeus amarus, carp Cyprinus carpio, catfish Silurus glanis, goldfish Carassius auratus, pope Gymnocephalus acerina, monkey goby Neogobius fluviatilis, common minnow Phoxinus phoxinus, stone eel Lampetra mariae, sabrefish Pelecus cultratus sometimes occur.