LAND MAMMAL FOSSILS
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LATE TRIASSIC PERIOD TO PRESENT 220 million years ago to present day The word MAMMAL describes the very characteristic that sets this class of vertebrates apart from all others. "Mammal" is derived from the Latin word 'mamma', which means breast. Unique to these creatures, all female members of each species possess mammary glands, and nurture their young with their milk. Another chief characteristic is the presence of hair. Hair aids mammals to maintain a constant body temperature which is also a mammalian characteristic. Of all vertebrates, mammals can sustain the longest duration of activity regardless of how adverse the surrounding environment is provided an ample food energy source is available.
The first mammals emerged in the Late Triassic Period, 220 million years ago, but never gained a dominant presence and broad diversity until the Miocene Period, 15 million years ago. The warming and cooling of the earth during the Great Ice Age of the Pleistocene, 2 million years ago, gave rise to the emergence of enormous land mammals. All of these impressive beasts died out during the Pleistocene Era, about 12,000 years ago.
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During the Triassic, the earliest known mammals looked like small rodents and belong to a subclass called Prototheria. The only survivors of this subclass today are the Spiny Anteater and the Duckbilled Platypus.
Throughout the era of dinosaurs ruling the planet, mammals only existed as small shrew-like creatures. It wasn't until close of the Cretaceous and the final demise of the dinosaurs 65 million years ago that mammals shared the planet with flowering plants, insects, and birds as the dominant life forms. By the Eocene, around 50 million years ago, mammalian development gave rise to many of the forerunners of today's animals. This section is dedicated to LAND MAMMALS as marine mammals such as whales are featured in the MARINE VERTEBRATES SECTION. Common misspellings: mamal, mammel, sabre-tooth tiger, mammuth, mamuth, mastadon, mastadan, rino, casteroides, castorides, castoredes, ursus spelus, ursus spelaus, ursus speleaus, ursus speles, auroch, wolly rhino, woolly rhino, wolly mammoth, taper, lama, woolly mammoth. Special thanks to the highly talented artist TODD MARSHALL for permission to feature his artwork in this section. All images and text on this site are protected by copyright and may not be used in any way. |
During the
Pleistocene, gigantism among many mammals was the rule. There
were elephant-size mastodon and wooly mammoth, a 5 ton ground sloth called
Megatherium, measuring 20 feet long, a giant beaver Castoroides, that grew
as big as a bear and bison with horns that spanned 10 feet across!
Another
area of intense interest is that of the large carnivores. All
mammals of the large order Carnivora are carnivores or
"meat-eaters" although not all carnivores just eat meat.
They are identified by their characteristic pair of meat-slicing teeth
known as 'carnassial teeth'. All but one type of toothed-whales are
excluded from this order. There was the giant cave bear Ursus
spelaeus, Canis dirus - the ferocious dire wolf, and most notorious of
all, the terrifying saber cats such as Smilodon with a jaw that could open
120 degrees, allowing its massive pair of saber teeth in its upper jaws to
be driven into its unfortunate victim.
