2007-07-15 03:34:32 · 20 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
Here is a cut and paste of an answer I gave on this topic a few weeks ago:
While all mammals do indeed breathe air, that is not a feature that defines the mammallian class - it is shared by all terrestrial vertebrates (i.e. reptiles, birds and mammals).
Live birth is also a feature of most (but not all) mammals - but is not a defining character.
Warm bloodedness is a poorly defined trait, with different degrees of endothermy present in different organisms. It is also not a specifically mammalian trait.
To be defined as a mammal, an organism must possess the following:
- The female produces milk to feed its young (the mammary glands that produce this milk give the group its name: Mammals). This is the main, number one, defining characteristic - shared by all living mammals (including egg-laying platypus and echidna). Unfortunately, it's hard to see in fossil forms.
- The possession of hair. Although some other groups of critters (including some insects) have what appears to be hair, no other animal has hair with the same form and origin. Again, this doesn't show up well in fossils.
- The lower jaw is a single bone on either side. All other groups of vertebrates have more than one bone on each side of the jaw.
- The middle ear contains 3 bones (ossicles). These bones were once part of the lower jaw (in reptiles), but became involved in transferring vibration to the tympanum. This is the absolute defining feature for mammals in skeletal remains. No other group of animals possesses this trait.
- The main artery leaving the heart curves to the left, becoming the aortic arch. In birds it curves to the right, and other groups of vertebrates have more than one main artery leaving the heart.
- Muscular diaphragm that separates the body cavity into two sections. Used in breathing.
Sharks have none of these features, and are not considered mammals.
2007-07-15 03:43:54 · answer #1 · answered by Anonymous · 0⤊ 1⤋
A shark is a large fish, not a mammal. This is because the shark cannot produce milk to feed their young. You are confused because a whale IS a mammal; it has live young that it produces milk for, and it breathes air. The shark is just a fish, and it does not breath air. Hope this helps. Do you even own a dictionary??? lol
2007-07-19 02:36:57 · answer #2 · answered by ravenstorm_charmed 1 · 0⤊ 0⤋
Sharks are fish, but some do produce live young. But it is not in the same way mammals do. The eggs actually hatch inside the shark and then it gives birth. Some snakes also give birth by this process and they are reptiles. The technical term is called Ovoviviparous.
2007-07-15 05:36:40 · answer #3 · answered by Med Tech 1 · 0⤊ 0⤋
No, a shark is not a mammal because it breaks many of the rules that tell whether something is a mammal or not.
a) It does not have hair all over its body
b) It does not have lungs, it has gills.
I can't think of any others at the moment, but they are clearly not mammals.
2007-07-15 03:40:13 · answer #4 · answered by Anonymous · 0⤊ 0⤋
NO shark is a mammal. ALL sharks are fish. it just so happens that the eggs hatch INSIDE the mother, and so they APPEAR to give live birth. Many snakes give live birth, too, but no snakes are mammals. The Austrailian Platypus is a mammal, but it lays eggs. Whether an animal gives live birth or lays eggs is not the PRIMARY determination of whether it is a mamal or not.
2016-05-18 01:39:35 · answer #5 · answered by ? 3 · 0⤊ 0⤋
Sharks are fish because they have gills, lay eggs (There inside then come out alive), and don't have any type of hair. Mammals have fur or a type of hair, lungs, and give live birth.
2007-07-15 05:59:58 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Have you been to school? Does it have fur or hair somewhere around its body? If not, it's not a mammal. You see the slits around the neck of the shark? Those are its gills. If it has gills, it's a fish.
2007-07-15 11:49:59 · answer #7 · answered by S N 3 · 0⤊ 0⤋
Shark is not a mammal. Shark is a fish made up of cartilage. (Whales are the one mamals.)
Do not be confused with a whale shark which has a "whale" in its name . Whale shark is a kind of shark and not a whale. In fact, whale shark is the largest fish in the world.
2007-07-15 10:00:04 · answer #8 · answered by ♥ lani s 7 · 0⤊ 0⤋
A shark is a fish that has cartilage instead of bone.
It has gills like a fish. Sea going mammals like whales and dolphins have blowholes and need to surface and breathe air.
And no, they don't have mammary glands either.
2007-07-15 03:42:31 · answer #9 · answered by John M 2 · 0⤊ 0⤋
Sharks are not mammals because they do not produce milk for their young.
2007-07-15 03:37:34 · answer #10 · answered by Rodztah 1 · 0⤊ 0⤋