Wallace's Zoogeographical Realms

SYED MUHAMMAD KHAN (BS HONS. ZOOLOGY)
pg. 1
Wallace’s Zoogeographical Regions
“A zoogeographical region/realm is a sub-division of the Earth having a unique
fauna, i.e. species that are found only in that area.”
Alfred Russel Wallace, who is referred to as the “father of zoogeography”, published a
classical work: “The Geographical Distribution of Animals” in 1876, in which he chose
mammals as model organisms to study animal distribution, and divided the world into six
zoogeographical realms. The six zoogeographical regions and their sub-regions (four each)
given by Wallace are as follows:
 Palearctic Region, sub-regions: European, Mediterranean, Siberian and Manchurian.
 Ethiopian Region, sub-regions: East Africa, West Africa, South Africa, and Malagasy.
 Oriental Region, sub-regions: Indian, Ceylonese, Indo-Chinese, and Indo-Malayan.
 Australian Region, sub-regions: Austro-Malayan, Australian, Polynesian, and New
Zealand.
 Neotropical Region, sub-regions: Chilean, Brazilian, Mexican, and Antillean.
 Nearctic Region, sub-regions: Californian, Rocky Mountains, Alleghany, and Canadian.
Figure: Zoogeographical regions of the world – according to A. R. Wallace.
Palearctic Region
The Palearctic region is the largest among the six zoogeographical regions of the world. It
covers about 14,000,000 square miles. It stretches across all of Europe, Asia north of the
foothills of the Himalayas (northern part of China, Transoxiana, Russia, Japan, Iran,
Afghanistan, Balochistan, etc.), North Africa, and the northern and central parts of the

pg. 2
Arabian Peninsula. There is a resemblance in the fauna of the Nearctic and the Palearctic
regions so they are sometimes grouped as the Holarctic region.
 Climate: The climate of the Palearctic region is more or less temperate. There is a great
fluctuation in temperature and the amount of rainfall in the region.
 Biomes: It includes wet forest land, dry open steppe land, deserts, and large coniferous
forests.
 Topographical Features: There is great diversity of surface features such as mountains,
water, clay, sand, and limestone of different compositions.
 Sub-regions: The Palearctic region has four sub-regions: (1) European sub-region
(northern and central Europe, Black sea and Caucasus), (2) Mediterranean sub-region
(remaining parts of Europe; Africa and Arabian portions), (3) Siberian sub-region (northern
Asia and Himalayas) and (4) Manchurian sub-region (Mongolia, Japan, Korea, and
Manchuria / China).
 Boundaries: The boundaries of the Palearctic region are as follows:
o North: It is bordered by the Arctic Ocean.
o West: It is bordered by the North Atlantic Ocean.
o East: It is bordered by the Pacific Ocean.
o South: It is bordered by the Ethiopian and Oriental regions. It is separated from the
Ethiopian region by the Sahara desert and the Oriental region by the Himalayan
Mountains.
Figure: Palearctic region (highlighted red).
Zoological Characteristics of Palearctic Region
The fauna of the Palearctic region is not very unique, the details are as follows:

pg. 3
Freshwater Fish: Fish fauna includes catfish, anabantids, cyprinids (family Cyprinidae),
paddle fishes, etc. Cyprinids are the dominant freshwater fish.
Paddlefish Common Carp (family Cyprinidae)
Danube / European / Wels Catfish
Amphibians: Amphibian fauna includes frogs, toads, salamanders, newts, and caecilians
(legless amphibians that live on the upper loose surface of the soil). Some noticeable tree
frogs include: Hyla spp. and Rhacophorus spp.
European Tree Frog (Hyla spp.) Wallace’s Flying Frog (Rhacophorus spp.)
Common Midwife Toad Fire Salamander

pg. 4
Reptiles: Reptilian fauna includes turtles, alligators, lizards, skinks, chameleons, agamids
(lizards), and snakes (vipers, cobras, pythons, etc.).
European Turtle Common / European Adder (Viper)
Chinese Alligator
Birds: Avian fauna includes cuckoos (only the males cry), ducks, finches, grebes, loons, hawks,
thrushes, swifts, woodpeckers, kingfishers, etc.
Cuckoo Goldfinch Eurasian Sparrow-hawk
Common Kingfisher Song Thrush

pg. 5
Mammals: Mammalian fauna includes members of the order insectivore (insect-eating
mammals), which is the most primitive order of placental mammals (hedgehogs, moles,
shrews). Other mammals include rabbits, deer, oxen, sheep, camels, bears, and cats. This
region also contains two endemic rodents: Spalax spp. – a brownish yellow, tailless,
burrowing rat, and Selevinia spp. – a dormouse discovered in Kazakhstan, in 1938.
Long-eared Hedgehog Eurasian Brown Bear Bactrian Camel
Mongolian Wild Horse Giant Panda
Desert dormouse (Selevinia spp.) Mole Rat (Spalax spp.) Red Deer
Putorana Snow Sheep Saiga Antelope Alpine Long-eared Bat

pg. 6
Ethiopian Region
The Ethiopian region includes the whole of Africa (south of the Sahara desert), some southern
parts of Arabia, and Madagascar (however, its fauna is entirely different, it may be treated as
an ancient continental island as it separated from the mainland in the late Cretaceous period).
According to some authors, the fauna of Oriental and Ethiopian regions is similar, hence they
are sometimes grouped as the Paleotropical region.
 Climate: The climate is tropical because the region is present in the tropics. The conditions
for life are more stable, uniform, and favorable. In winter, the temperature is 20-30oC but
still higher in Central Africa. The distribution of animals is more influenced by moisture
than temperature.
 Biomes & Topography: There are large rivers, grasslands, semi-desert land, deserts, and
mountains.
 Sub-regions: This region has four sub-regions: (1) East Africa, (2) West Africa, (3) South
Africa, and (4) Malagasy (Madagascar).
 Boundaries: It is surrounded by sea (the Atlantic Ocean to the West and the Indian Ocean
to the East) except from the North where it connects with the Palearctic region through
the Sahara desert.
Figure: Ethiopian region (highlighted blue).
Zoological Characteristics of Ethiopian Region
There are many similarities between the fauna of Ethiopian and Palearctic regions.
Freshwater Fish: Fish fauna is primitive and includes: lungfish (Protopterus spp.), catfish,
cyprinids, and cichlids. Lungfish live in regions where seasonal droughts are common. When
freshwater lakes and rivers begin to stagnate and dry, these fish use lungs to breathe air.
Protopterus spp. is found in freshwater rivers and lakes in tropical Africa. It can survive when
rivers or lakes are dry by burrowing into the mud. It keeps a narrow air pathway open by
bubbling air to the surface, the mud dries up and the fish remains in aestivation (prolonged

pg. 7
dormancy during a hot or dry period) until rainfall. When rain again fills the lake or riverbed,
the lungfish emerges from its burrow to feed and reproduce.
Labeobarbus spp. (family Cyprinidae) Spotted Tilapia (Cichlid)
Spotted Lungfish (Protopterus spp.)
Amphibians: Amphibian fauna is not rich. Frogs and toads are very common, tailed
amphibians are absent, but caecilians are present. Among frogs, one family – Pipidae is
notably and exclusively found in this region. These frogs are present in water and spend their
whole life in water, their hind limbs are completely webbed. All other frogs tend to live on
land at moist places and enter the water only for breeding.
African Dwarf Frog (family Pipdae) African Caecilian
Reptiles: Reptiles are represented by turtles, crocodiles, agamids (lizards), skinks,
chameleons, and snakes (cobras, vipers, typhlops – blind snakes, pythons, black mamba, etc.).
Many species of chameleons are present here.

pg. 8
African Chameleon African Spurred Tortoise
Black MambaAfrican Nile Crocodile
Birds: Bird fauna includes cuckoos, bee-eaters, goatsuckers, owls, ostriches, orioles, sunbirds,
storks, thrushes, woodpeckers, and weaver birds.
Olive Bee-eaters Marabou Stork Ostrich
Mammals: Mammals are represented by gorillas, chimpanzees, monkeys, hedgehogs, moles
(golden mole is a unique species), shrews (otter shrew and elephant shrew are unique),
hippopotamuses, giraffes, tenrecs (rodents found only in the Ethiopian region), aardvarks,
rhinoceros, elephants and scaly ant-eaters. Many of these are endemic like golden mole,
elephant shrew, gorilla, chimpanzee, and tenrecs. Other mammals include lions, leopards,
hyenas, and antelopes.

pg. 9
Lion Hippopotamus Gorilla
Tail-less Tenrec Giraffe African Elephant (Female)
Brown Hyaena Chimpanzee Zebra
Golden Mole Elephant Shrew Giant Otter Shrew
Oriental Region
The Oriental region includes Asia and its tropical countries, Pakistan (excluding Baluchistan),
India, Sri Lanka, Burma, Indonesia, Bhutan, Islands of Borneo, Philippines, Java, and Sumatra.
The fauna of the Oriental region is similar to the Ethiopian region, hence they are sometimes
grouped as the Paleotropical region.

pg. 10
 Biomes & Topography: It shows great diversity in physical features. The northern part is
composed of grassy plains with scattered bushes and trees. The North and West sides are
composed of deserts. The southern part is rich in vegetation. Sri Lanka, Malaysia, and
Indonesia are composed of thick tropical rainforests.
 Climate: The climate is tropical. The temperature in the south is almost constant (about
30oC) but rises in summer. In the northern regions, in autumn and winter, the
temperature lies between 10-20oC, rising in spring and summer.
 Sub-regions: This region has four sub-regions: (1) Indian, (2) Ceylonese (Sri Lanka), (3)
Indo-Chinese, and (4) Indo-Malayan.
 Boundaries:
o North: It has a land connection with the Palearctic region via the Himalayan
Mountains.
o South-West: It is surrounded by the Indian Ocean.
o South-East: It is surrounded by the Pacific Ocean.
o Boundary with the Australian Region: The Malayan Archipelago (in the east) spreads
out and reaches the Australian region, the distinction between these two regions is
made by the transitional zone Wallacea (see pages 51-52).
Figure: Oriental region (highlighted mustard-yellow).
Zoological Characteristics of Oriental Region
Freshwater Fish: Many species of carps, catfish, and anabantids are characteristic of the
freshwater fauna of the Oriental region. Freshwater fauna does not include any primitive
fishes.

pg. 11
Rohu (family Cyprinidae) Dwarf Gourami (Anabantid)
Goonch Catfish (famous for killing people in the Kali River, India)
Amphibians: It includes caecilians, frogs, and toads. Tree frogs and tailed amphibians are
absent.
Indian Bullfrog Asian Toad Indian caecilian
Reptiles: Reptilian fauna is diverse. Turtles, such as the big-head turtle (Family Platysternidae)
are present. Crocodiles are present in tropics of the Oriental region. Gavials (family
Gavialidae; long-nosed crocodilians) are also present. Geckos, chameleons, Varanus spp.
(monitor lizards) and skinks are four famous lizards. Oriental region is famous for several
venomous snakes like vipers, kraits, cobras, and typhlops (blind snakes). According to a rough
estimate, around 30,000 people are killed by snake bites in Asia each year, especially in
Burma. Uropeltidae (shield-tailed snakes) and Xenopeltidae (egg-eating snakes) are unique
families of snakes. Pythons are also present.

pg. 12
Indian Cobra Indian Rock Python Indian Spotted (Pond) Turtle
Wild Water Monitor (Varanus spp.) Indian Gavial (Gharial) Mugger Crocodile
Birds: Bulbul, bluebirds, bee-eaters, kingfishers, woodpeckers, thrushes, owls, weaver birds,
broad-bills are unique and endemic birds of this region.
Long-tailed
Broadbill
Blue Bearded Bee-
eater
Baya Weaver White-naped
Woodpecker
Red-vented Bulbul Asian Koel (Left: Male, Right: Female) Falcon
Mammals: Orangutans and gibbons are found in rainforests of Borneo. Monkeys, tarsiers
(Tarsius spp. – a small, arboreal, nocturnal mammal), Indian Elephants (Elephas maximus),
Rhinoceroses (Rhinoceros unicornis), tapirs, black bucks (Antilope cervicapra), Bubalus (a
genus of wild bovines), moles, shrews, hedgehogs, tigers, sloth bears (found only in India),
four-horned antelopes, cows (Bos spp.) are found in Oriental region.

pg. 13
Bengal Tiger Sloth Bear Indian Pangolin (Scaly Anteater)
Indus River Dolphin Black Buck Indian Elephant (Male)
Orangutan Lar Gibbons (Pair) Tarsier (Tarsius spp.)
Australian Region
The Australian region includes the whole of Australia, New Guinea, Tasmania, a few of the
smaller islands of the Indonesian Archipelago, New Zealand, and other Pacific Islands.
Australian and Neotropical regions are present in the Southern hemisphere (Notogaea) while
all others are present in the Northern hemisphere.
 Climate: The climate is partly tropical, partly temperate. Areas in the south are temperate,
New Guinea is tropical and Tasmania is temperate.
 Biomes & Topography: In the interior of Australia, hot arid plains and deserts are found.
Thick forests are also present in the northern, eastern, and southern regions.
 Sub-regions: This region has four sub-regions: (1) Austro-Malayan, (2) Australian, (3)
Polynesian, and (4) New Zealand.

pg. 14
 Boundaries: It is the only region that does not have any land connections whatsoever with
the world. It has the following boundaries:
o Pacific Ocean: Eastern boundary (including Northeast and Southeast).
o Indian Ocean: Western boundary (including Northwest and Southwest).
o Boundary with the Oriental Region: The distinction between the Australian and
Oriental regions is made by the transitional zone Wallacea (see pages 51-52).
Figure: Australian region (highlighted orange).
Zoological Characteristics of Australian Region
There are many reasons to believe that Australia separated from the rest of the world in the
late Cretaceous period, because during that period there were only marsupials and
monotremes. This region is characterized by the absence of placental mammals and the
presence of very primitive animals. It is known as the “veritable museum of archaic animals”.
Bats, rats, and other placental mammals were introduced by man later on.
Freshwater Fish: Freshwater fish fauna is primitive, the Queensland Lungfish (Neoceratodus
spp.) and osteoglossids (Arowana) are characteristic of the Australian region. Neoceratodus
spp. inhabits the freshwaters of Queensland, Australia. It survives stagnation by breathing air,
but it normally uses gills and cannot withstand total drying.
Queensland Lungfish (Neoceratodus spp.) Australian Arowana (Osteoglossid)

pg. 15
Amphibians: It is the only region where the common toad is absent. Frogs and tree frogs are
present. Tailed amphibians and caecilians are also absent.
Leaf Green Tree Frog Striped Burrowing Frog
Reptiles: Two exclusive families of reptiles, Carettochelyidae (pitted shelled turtles) and
Pygopodidae (legless lizards) are found here. A third family of reptiles called Sphenodontidae
is found only in New Zealand, it has only one member – the Tuatara (Sphenodon punctatus).
Lizards include Varanus spp. (monitor lizards), geckos and agamids. The largest lizard – the
Komodo dragon, is found in the Indonesian islands of Komodo. Snakes include typhlops,
pythons, cobras, and elapids. Saltwater crocodile is also present.
Tuatara – Living Fossil
(found in New Zealand only)
Komodo Dragon
(The largest lizard)
Burton’s Legless Lizard
(family Pygopodidae)
Pig-nosed Turtle
(family Carettochelyidae)
Diamond Python Salt-water Crocodile
(The largest crocodile)
Birds: Australian region is rich in bird fauna. Parrots and pigeons are present. It is famous for
running birds like emus, cassowaries (in New Guinea), and kiwi. Kingfishers, honey-eaters,

pg. 16
bowerbirds, birds of paradise are also common. There are no finches, woodpeckers, and
pheasants.
Emu (Australia) Kiwi (New Zealand) Cassowary (New Guinea)
Bird of Paradise Regent Honey-eater Bowerbird
Mammals: Australian region is famous for primitive mammals. Placental mammals are
absent, except for those which were later introduced by European settlers. Egg-laying
mammals have one order – Monotremata which includes two families Tachyglossidae
(Echidna – spiny anteaters) and Ornithorhynchidae (Ornithorhynchus spp. – Platypus).
Platypus is aquatic, has short legs, and webbed feet. Echidna is terrestrial, the upper part of
its body is covered with spines and its tail is hairy. Both of these provide a link between
reptiles and mammals. Australian region is the real home of marsupials, although they are
also found in North and South America. The basic character of marsupial mammals is the
presence of a pouch/marsupium in females where the babies are carried and nourished by a
duct from the mammary glands. The pouch opens anteriorly but sometimes also posteriorly.
Sometimes, the pouch is absent and two flaps of skin act as a marsupium. Examples of
marsupials include kangaroos, wallabies, Tasmanian wolves, bandicoots, koalas, etc.

pg. 17
Koala Wallaby Kangaroo
Echidna (Spiny Anteater) Duckbill Platypus Tasmanian Wolf (Extinct)
Neotropical Region
The Neotropical region includes the whole of South and Central America, West Indies, and
most of Mexico. Australian and Neotropical regions are present in the Southern hemisphere
(Notogaea) while all others are present in the Northern hemisphere. The neotropical region
separated from the rest of the world in the Eocene epoch.
 Climate: The climate is mostly tropical. The southern region extends into the temperate
zone.
 Biomes & Topography: It has a very rich tropical rainforest. The Amazon River receives a
high rainfall, year-round. It is the only zoogeographical region without any desert. Andes
chain is a very high mountain range in this region. The southern part of these mountains
is covered with grassy plains and no trees, the temperature becomes very low in the
winter.
 Sub-regions: This region has four sub-regions: (1) Chilean, (2) Brazilian, (3) Mexican, and
(4) Antillean.
 Boundaries: It is connected to the Nearctic region in the North through the Isthmus of
Panama. All other sides are surrounded by water (the Pacific Ocean in the West and the
Atlantic Ocean in the East).

pg. 18
Figure: Neotropical region (highlighted purple).
Zoological Characteristics of Neotropical Region
This region has a unique, diverse, and very rich fauna. The Neotropical region has the
maximum number of endemic families because it is separated from the rest of the world in
the Eocene epoch.
Freshwater Fish: A very primitive fish – South American Lungfish (Lepidosiren spp.) is found
here. Other fishes include gymnotids, eels, osteoglossids, garpikes, etc. Lungfish live in regions
where seasonal droughts are common. When freshwater lakes and rivers begin to stagnate
and dry, these fish use lungs to breathe air. Lepidosiren spp. is found in freshwater rivers and
lakes in tropical South America. It survives by using the same strategy as Protopterus spp.
South American Lungfish (Lepidosiren spp.) Electric Eel (family Gymnotidae)
Zebra Knife-fish (family Gymnotidae) Silver Arowana (family Osteoglossidae)

pg. 19
Amphibians: Amphibian fauna is moderately rich having all groups. Caecilians are present in
the tropics. Common frogs, toads, tailed amphibians (only Oedipus spp. – a salamander that
doesn’t have any lungs), and tree frogs are present.
Gamboa Worm Salamander (Oedipus spp.) Dyeing Dart Frog (Poisonous)
Reptiles: Reptilian fauna is very rich. It includes snakes, turtles, crocodiles, caimans (South
American crocodilian alligatorid), lizards, geckos, agamids, and tegu (a species of lizard).
Tegu Rainbow Whiptail
(Cnemidophorus spp.)
Yellow-footed Tortoise
South American Bushmaster Anaconda Caiman
Birds: Avian fauna is also very rich, diverse and so strange that sometimes Neotropical is
called “bird continent”. Rhea spp. and Tinamou spp. are flightless birds endemic to this
region. Other bird species include kingfishers, cuckoos, hoatzins, macaws, and hummingbirds.

pg. 20
Greater Rhea Elegant-crested Tinamou
Blue and Yellow MacawBlack-hooded Sunbeam Hoatzin
Mammals: Maximum number of endemic mammals are found in this region. Edentata
(sloths, anteaters, armadillos, etc.) are exclusive to this region. Armadillos are, however, also
found in the Nearctic region. Sloths (family Bradopodidae) are arboreal animals, completely
adapted for arboreal life, and cannot walk on land. Ant-eaters (family Myrmecophagidae) eat
termites and have a long tubular mouth. Armadillos (family Dasypodidae) also feed on ants
and have bony plates covering their body, arranged in rings. Two families of marsupials are
present, namely Didelphidae (opossum) and Caenolestidae (marsupial rats). Cebidae (New
World monkeys, order Primates) and Marmosets are also present. These monkeys are
variously colored and small-sized. All apes are absent. Ungulates are remarkable and unique
like deer, pigs, oxen, goats, sheep, llamas (Camelidae), and tapirs (having long prehensile
nose). Members of the order Insectivora are absent from the Neotropical region, but blood-
sucking bats are present. Jaguars are the only pantherine felids (cats) found in this region.
Anteater Armadillo

pg. 21
Sloth Llama Jaguar
Brown-eared Woolly
Opossum
Panamanian White-faced
Capuchin (family Cebidae)
South American Tapir
Nearctic Region
The Nearctic region includes the whole of North America, some parts of Mexico, and the
whole of Greenland.
 Biomes: Greenland is arctic and is completely buried beneath a mass of ice of unknown
thickness. The eastern part of North America is composed of deciduous or mixed forest.
The middle part has grasslands. The northern portion is composed of coniferous forests.
 Climate: In the northern parts, the temperature is lower in the winter as compared to the
same latitudes of the Palearctic region. Life is very rare as few animals can survive in an
area with frozen soil.
 Sub-regions: This region includes four sub-regions: (1) Californian, (2) the Rocky
Mountains, (3) Alleghany, and (4) Canadian.
 Boundaries: It is connected to the Neotropical region in the South via the Isthmus of
Panama. All other sides are surrounded by water (the Pacific Ocean in the West, Atlantic
Ocean in the East, and the Arctic Ocean in the North).

pg. 22
Figure: Nearctic region (highlighted green).
Zoological Characteristics of Nearctic Region
There is a striking resemblance in the fauna of the Nearctic and Palearctic regions (despite
some minor differences), hence they are sometimes grouped as the Holarctic region.
Freshwater Fish: Fish fauna includes paddlefish, catfish, cyprinids, bowfins, gars, etc.
Bowfin Alligator Gar
Amphibians: Amphibian fauna is moderately developed. Tailed amphibians are abundant,
represented by salamanders, the axolotl (salamander species), and Siren spp. (salamander
species). Frogs and toads are also present. There is a unique endemic frog – Aschaphus spp.
Like other frogs, it does not have a tail but does have tail-wagging muscles indicating that this
frog originated from some tailed ancestor.
Tailed Frog (Aschaphus spp.) Lesser Siren (Siren spp.) Axolotl
Reptiles: Reptilian fauna is rich and includes turtles, crocodiles, alligators, coral snakes,
typhlops (blind snakes), and pit vipers. Lizards include geckos, anguids, skinks, and Heloderma

pg. 23
spp. (Gila monsters). Heloderma spp. is the only venomous lizard in the world, the venom
glands are present in the lower jaw, not in the upper jaw as in snakes.
Red Ear Slider Gila Monster (Heloderma spp.)
Western Diamondback Rattlesnake American Alligator
Birds: Avian fauna includes cranes, hummingbirds, hawks, herons, vultures, thrushes,
woodpeckers, and many other birds. Among these, turkeys are the most unique.
Wild Turkey Acorn Woodpecker Common Black Hawk
Bald Eagle Broad-tailed Hummingbird

pg. 24
Mammals: Mammals include bison, cougars, opossums, moles, leaf-nosed bats, bears, deers,
jumping mice, flying squirrels, and armadillos. A unique family of artiodactyls is present in the
region – Antilocapridae, they have characters of both: bovids and deers – horns are
unbranched and shed annually (bovids have permanent unbranched horns, whereas deers
have branched horns that shed annually).
American Bison Pronghorn Antelope Meadow Jumping Mouse
Northern Flying Squirrel Leaf-nosed Bat Moose (Male)
American Black Bear North American Cougar

Wallace's Zoogeographical Realms

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