text: can you breed a dog with a cat?   i wouldn't suggest trying it.  i'm pretty sure there are both prezygotic and postzygotic barriers to this type of hybridization. that is to say, you probably couldn't get them to mate, and, even if you could, the sperm and egg would not recognize each other and fuse. and, if, by some miracle, you managed to pull this off, there are enough genetic differences (different genes, different chromosome organization, different number of chromosomes, etc) would be so many developmental problems that there is no chance it could survive to term.  bird and dinosaur is even less likely; the last common ancestor between cats and dogs, miacidae (or one of its relatives), lived 40 million years ago. in contrast, archaeopteryx, which is thought to be one of the earliest birds, lived some 150 million years ago. if you add the time cats and dogs have been diverging from miacidae together, it's still only about half the time since birds have been diverging from the relatives of their dinosaur ancestors.