>>42614935
I've changed my position on this back and forth. The truthful (but also kinda bullshit) answer is that we can't accurately guess without more concrete examples of how exactly half-and-half creatures work in Equestria.
Clearly all of the chimeras MUST be magical or at least have come from magic originally, because you can't just sew a lion onto an eagle without it dying instantly unless magic is involved. And that magic MUST necessarily be actively making changes to the biology of both animals so they can even be alive at all. But how they are made, and what the magic is specifically doing to make the creature functional matters a lot.
It's NOT necessarily the case that it's going to be the most biologically obvious choice. Why would a creature that is chaotic down to DNA level obey the laws of normalcy? Why would their biology tend toward being obvious, and mundane? I think they'd have a tendency not to be. A chimera doesn't HAVE to follow the rules of normal evolution at all, it just has 2 animals as a base to work with, and the magic can kinda go in any direction it wants with them in theory. There is no reason a Lamia can't have 5 vaginas and 7 eyeballs if that's something the magic decides to do. Neither lions nor eagles are sapient, but Griffons are. Neither Ponies nor lions are house-sized but sphinxes are (also lions do not have slit pupils). Clearly the process of making a chimera sometimes gives them traits that neither of their base animals has.
THE TRUE ANSWER IS WHO EVEN FUCKING KNOOOOOWS
