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Mammalia (mammals)
Life
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Sarcopterygii (lobe-finned fish) > Stegocephalia
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(mammal-like reptiles) > Therapsida > Theriodontia >
Cynodontia
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Aepyceros melampus
(Impala) fawn suckling from mother. Production of milk for feeding of infants is
one of the defining characteristics of mammals. [photo
Arno
Meintjes ©] |
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What defines a mammal?
Mammals are animals with backbones that have
the following unique characteristics:
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hairy - in most species the hair
covers the body, thus providing insulation;
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milk producers - mothers provide milk
for their young.
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There have been various modifications of the
skull in mammals, including the forming of a secondary pallet,
which enables an individual to breath through the nose while eating.
Classification
Mammals are divided into three main groups:
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Monotremes (echidnas, Platypus)
The most obvious characteristic of this group is
that females lay eggs rather than giving birth to live young like
the majority of modern-day mammals. This group contains a single extant
order, the Monotremata, which contains two families:
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Family: Tachyglossidae (spiny anteaters / echidnas).
Found in Australia and New Guinea.
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Family: Ornithorhynchidae (Platypus).
Contains the single species the Platypus (Ornithorhynchus) found
in eastern Australia and Tasmania.
Extinct orders in the Prototheria include
Multituberculata, Triconodonta and Docodonta. |
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Marsupials (opossums,
Koala, kangaroos and others)
Give birth to highly undeveloped (altricial) young
that are nurtured in a pouch on the female that encloses the mammary
glands. This means that they can have mum's milk on tap in a safe and
protected environment. Marsupials are only found in the Australian region
(including New Guinea) and in the New World (Americas).
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Placentalia (placental mammals)
Give birth to live young. The embryo in the mother
is attached to the placenta via an umbilical cord. Most mammals fall
within this group and all mammals indigenous to Africa are in this group. |
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Bibliography
The following works have been used in the
production of the mammal pages:
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Stuart, C
& T. 2001 Chris and Tilde Stuart’s field guide to the
mammals of southern Africa. Struik Publishers, South Africa
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Lawlor,
T.E. 1979. Handbook to the orders and families of living
mammals. Mad River Press California, USA
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Smith,
S.J. 1985. The atlas of Africa’s principal mammals. Natural
History Books, South Africa.
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MacDonald,
D.W. (ed). 2006. The encyclopedia of mammals. Oxford
University Press, U.K.
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Skinner,
J.D. & Chimimba, C.T.(eds). 2005. The mammals of the
southern African subregion (3rd edition).
Cambridge University Press
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Taylor, P.J.. 2000. Bats of Southern
Africa. University of Natal Press, Pietermaritzburg.
Text by Hamish Robertson |
