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Mammals (formally Mammalia) are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain. Mammals are divided into three main infraclass taxas depending how they are born. These taxas are: monotremes, marsupials and placentals. Except for the five species of monotremes (which lay eggs), all mammal species give birth to live young. Most mammals also possess specialized teeth, and the largest group of mammals, the placentals, use a placenta during gestation. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart. There are approximately 5,400 species of mammals, distributed in about 1,200 genera, 153 families, and 29 orders (though this varies by classification scheme). Mammals range in size from the 30–40-millimetre (1.2–1.6 in) Bumblebee Bat to the 33-metre (110 ft) Blue Whale. Mammals are divided into two subclasses, the prototheria, which includes the oviparous monotremes, and the theria, which includes the placentals and live-bearing marsupials. Most mammals, including the six largest orders, belong to the placental group. The three largest orders, in descending order, are Rodentia (mice, rats, and other small, gnawing mammals), Chiroptera (bats), and Soricomorpha (shrews, moles and solenodons). The next three largest orders include the Carnivora (dogs, cats, weasels, bears, seals, and their relatives), the Cetartiodactyla (including the even-toed hoofed mammals and the whales) and the Primates to which the human species belongs. The relative size of these latter three orders differs according to the classification scheme and definitions used by various authors. Phylogenetically, Mammalia is defined as all descendants of the most recent common ancestor of monotremes (e.g., echidnas and platypuses) and therian mammals (marsupials and placentals). This means that some extinct groups of "mammals" are not members of the crown group Mammalia, even though most of them have all the characteristics that traditionally would have classified them as mammals. These "mammals" are now usually placed in the unranked clade Mammaliaformes. The mammalian line of descent diverged from an amniote line at the end of the Carboniferous period. One line of amniotes would lead to reptiles, while the other would lead to synapsids, including mammals. The first true mammals appeared in the Triassic period. Modern mammalian orders appeared in the Palaeocene and Eocene epochs of the Palaeogene period. From Wikipedia under the
GNU Free Documentation License What high school classes do i need to take in order to become a Marine Mammal Trainer? Q. i want to become a marine mammal trainer and i am a freshmen in high school.i need to know what classes i need to take in order to become one. Asked by Youkai - Fri Jul 20 18:22:30 2007 - - 5 Answers - 0 Comments A. If you want to train you should also pay attention to the behavioral sciences and develop a good understanding of classical and operant conditioning. You should also check into SCUBA lessons as certification is generally required. Of course anything you can do to get experience working with any type of animal is desirable. Apply for a job at a local pet store or volunteer your services to a local vet, nature center or zoo. Best of luck! Answered by Uh.Oh...Spaghettios - Fri Jul 20 18:57:51 2007 How much does a marine mammal veterinarian make? Q. i've been doing research and i can't seen to figure out if a marine mammal vet makes the same amount of money as a regular vet. Asked by becca rae - Wed Apr 23 01:36:05 2008 - - 1 Answers - 0 Comments A. Most specialists make more than regular veterinarians (dunno about the irregular ones.) They also have additional education and training, generally a residency on top of veterinary college. There aren't nearly as many, so the salary info isn't as available. Try contacting someone who may be able to give you the numbers or point you in the right direction: Answered by unknown - Wed Apr 23 14:34:44 2008 Can someone help me identify a fossil/possibly a tooth from a mammal?
Q. I have a very interesting fossil. It appears to be a tooth set in jawbone. The "tooth" itself measures 2 1/2" at its tallest point and 1 1/2" wide. It was found on the White River in N.W. Ark. It appears to be set in limestone. It is dirty white and almost cube shaped. The front of the tooth is clearly visible in the rock while most of the back is covered by stone/Jaw (?). I do suspect that it came from a mammal. Thanks. Asked by K - Tue Feb 27 13:08:10 2007 - - 5 Answers - 0 Comments A. If the tooth is set in the jawbone, and the jawbone is a single bone, then it's definitely a mammal. Furthermore, a wide tetrangular tooth is probably a cheektooth. Follow Haysoos' advice and take it to the nearest university that has Biology or Paleontology courses. Answered by Calimecita - Tue Feb 27 14:34:08 2007 From Yahoo Answer Search: "Mammal" See also:
 news.google.com Canada.com Whether it's a rotting seal on the beach or a live whale tangled in fishing gear, the BC Marine Mammal ... news.google.com StandardNet "The diademed sifaka has the reputation of being the most beautiful mammal on earth," Zeveloff said. "While I was in the central highlands of Madagascar, ... news.google.com Seacoastonline.com Marine mammals are protected by the Marine Mammal Protection Act, which makes it illegal to touch, harass or alter their normal behavioral pattern in any ... and more » From Google News Search: "Mammal"  naturetrek.co.uk 370px x 350px | 26.40kB [source page] Mammal Watching Holidays Polar Bear by Paul Stanbury  oregonstate.edu 532px x 793px | 153.00kB [source page] Liver Indialuk Injected Mammal 5 jpg  oregonstate.edu 531px x 784px | 89.80kB [source page] Bone Decalcified jpg 13 Feb 2006 15 03 108k Bone Marrow Mammal 1 jpg 13 Feb 2006 15 03 91k Bone Marrow Mammal 2 jpg 13 Feb 2006 15 03 90k Bone Marrow Section 1 jpg 13 Feb 2006 15 03 111k From Yahoo Image Search: "Mammal"  gather.com Dave L. Mon, 31 Aug 2009 00:32:38 GM A research group on sea . mammals. captured a rather odd por- poise on one of its trips. Its peculiarity was that it had feet. After they had photographed and measured the poor thing, they prepared to set . . .  ebook30.com Ebook30.com ue, 11 Aug 2009 11:10:14 GM Marine . Mammal. Populations and Ocean Noise Determining When Noise Causes Biologically Significant Effects edition PDF mb Throughout human 107230.  flickr.com (koller93) Sun, 23 Aug 2009 09:02:24 GM koller93 posted a photo: Dortmund grand tatou a 9 bandes a table jy 010809. From Google Blog Search: "Mammal" |
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