AFRICA - FAUNA Africa, together with the Deccan and West Australia as well as Brazil, forms part of the old continental mass of Gondwana land, whatever view one may take of the process of separation of each from the others. Gondwanaland seems to have persisted through much of the Mesozoic era, during which these southern lands were separated from the northern ones by the broad sea of Tethys, along which later uprose the great fold mountain ranges that stretch from the Pyrenees to the Malay. The southern lands thus show resemblances in their forms of life that are due to these old links. Another factor of the history of life within them is the stability of their conditions as contrasted with the wide variations that have occurred in the orography and climate of the northern lands. Those wide variations have been reflected in evolu tionary changes among living things and thus the northern lands have become in a large measure the homes where new forms are born, while the southern ones are largely refugees of early strays from the north, or places where certain types immigrating since connections were made have had a great career. The Sahara desert-barrier is largely a modern (post-glacial) hindrance to im migration of animals, the Rift system a partial but serious hin drance also relatively recently established.
The isolation of Africa is far less than that of Australia, and, whereas Australia retains the two lowly egg-laying mammals (Ornithorhynchus and Echidna) and is the great home of the mar supials, and of no other truly native mammals save bats, an indi cation of its long separation, Africa retains neither the egg-laying mammals nor the marsupials. The lowliest order of truly placental mammals, the so called Edentata, absent from Australia, occurs in South America, Africa and south-east Asia. Its great home is South America, but the aardvark (Cape ant-eater) is peculiar to Africa and Manis (the scaly ant-eater) has species both in Africa and in south-east Asia. It is an interesting fact that the order, though an ancient one is absent from Madagascar. The primates offer a contrasted distribution. Among them the lemurs are an cient forms of known fossil from the northern lands but now sur viving in Africa, Madagascar and south-east Asia; Africa has many more forms than south-east Asia and Madagascar many more still. From the lemurs have descended monkeys and apes; the platyr rhine monkeys are American, the catarrhine, African and Asiatic, including, among anthropoid apes, the orang-utan and the gibbon of south-east Asia and the gorilla and chimpanzee of intertropical Africa. It is generally thought that the survival of lemurs in Madagascar is a result of its separation from Africa before the great carnivores had spread thither. The absence of elephants, rhinoceros and anthropoid apes from Madagascar is noteworthy. The most important African carnivore is the lion, also found in parts of Arabia, Persia and western India and formerly more gen erally distributed in south-west Asia and north-east Africa until man restricted its range. The leopard (panther) and hyena are the other large carnivores. Madagascar has very primitive carni vores only, one of which was formerly said to be closely related to a West Indian form though the resemblances seem better in terpreted by the fact that both are ancient types. The African elephant is a species distinct from the Indian one ; the distribution of the genus was of course far wider until postglacial times. The hoofed animals of Africa are of some interest. Of even-toed forms Africa alone preserves the hippopotamus which ranged widely in northern lands until a late phase of the ice age ; remains of a small hippopotamus species have been found in Madagascar which also possesses a river hog (Potamochaeros). It is thought that they may have swum across from Africa before the separa tion between continent and island became very marked. The gi raffe and okapi are another family of hoofed animals found in East Africa only. The rhinoceros has east African and south-east Asiatic species. The single humped camel is now a feature of the steppes and deserts of north Africa but only as a domesticated animal introduced from Arabia. Deer are absent from Africa save for a few forms in French Africa, north of the Sahara, just as bears and wolves do not occur south of the desert. On the other hand the immense warm African grasslands are overrun by many antelopes, and the zebra and formerly the quagga. Africa thus, along with a number of old fashioned forms has several relatively new fashioned ones, but the absence of true cattle, pigs, goats, sheep and camels until man brought them is a striking fact. Of the genus Bos, nevertheless, South Africa possesses a representa tive in the Cape buffalo (Bos caller). Africa has many birds pe culiar to it but we need only notice the ostrich family of birds that run over grassland and desert border; extinct running birds of great size (Aepyornis) lived in Madagascar apparently not very long ago. Some African reptiles (e.g. Amphisbaena) appear closely related to South American forms, others to those of northern lands, the abundance of crocodiles is a feature and so are the chameleons, which especially abound in Madagascar. The python and puffadder are notable among African snakes. Monitor liz ards, abundant in Africa and elsewhere, have not reached Mada gascar. The Amphibians of Madagascar include several species also found in south-east Asia and this may be a result of an an cient land connection, and analogous arguments could be given concerning the land snails. Africa has the disastrous fate of being the one home of the tsetse fly.