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- All mammals produce milk to feed their young.
- The oldest, such as the platypus and the echidna, sweat their milk, while the rest developed nipples and mammary glands to feed their young.
- All mammals can produce their own internal heat, and most have fur to keep this heat inside their bodies.
- Most mammals give birth to live young. The only exceptions are the most ancient (as platypus and echidna), which still lay eggs.
- Mammals have a second palate, which divides the mouth from the nose canals, so they can eat and breath at the same time.
- Mammals also have cheek muscles. While reptiles swallow their food in almost entire pieces, mammals can move their jaws side to side with much more strength and dexterity. In this way mammals can chew their food into little pieces and get a lot more nutritional profit from it.
- Finally, they can walk with straight, upright legs, which support the body as pillars; unlike reptiles, that walk with the legs on their sides.
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| Platypus; photo by ccdoh1 cc-by-nc-nd |
Manatees ; photo by Flickkerphotos cc-by-nc-nd |
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Sources:
-The Rise of Placental Mammals, Kenneth D. Rose and J. David Archibald, 2005
-The Variety of Life, Colin Tudge, 2000
Citation: García, A.I. 2015. The Tree Of Nature (Online) at http://thetreeofnature.com
