I don't know, I don't think "Survival of the Fittest" has transitional animals.
I'm assuming that concept applies to critters that happen to be of one color where all the other ones of a different color stuck out like a sore thumb and were eaten, or they knew enough to migrate, or had better fighting skills etc
We do know that many plants and animals went extinct...probably because they weren't the fittest.
PS The biggest baddest males get all the chicks
Shouldn’t the biggest and baddest left fossils. Shouldn’t we be asking where they are just like Darwin did?
Pray for America