You really need to study some biology, this is getting silly. The scientific definition?
I'll reiterate: The animals that have hair also have mammary glands and inner-ear bones and bear live young (and share several more technical traits as well). True, the word mammal and mammary are cognate, but that's beside the point. The interesting thing is, there are two exceptions, which are only found in Australia: the platypus and the spiny anteater. They lay eggs, but share the other traits with mammals. Also, it's no longer clear that feathers are restricted to birds, as there were dinosaurs with feathers.
You should learn a little about what you speak of before spouting your verbal diarrhea.
That is also rude. Learn some manners while you're studying science.
I'm sorry but the only conclusion to be drawn from that is that birds and dinosaurs are the "same". So say the Darwinians.
And the platypus and the echidna are considered mammals just because they have incipient mammary glands. Look it up anywhere. Yes, many species of the same genus have similar traits - that is why they are in the same genus. However, there is always one trait which is deemed to be characteristic of it and whether they have the other traits or not, they are considered part of the genus if they have that trait.
More importantly though is the whole idea that if one trait is present then all the others are present. This is ridiculous - especially from an evolutionist point of view. Simultaneous development of totally unrelated traits at random is totally impossible. Also, that is the general problem with paleontology. If we are going to assume things from little evidence, we are never going to learn anything new, we are just going to justify pre-existing prejudices.