I have had an idea for a possible story, where the protagonists are some kind of future, sapient hominid descendants (Not descended from humans; bonobos or gorillas or something).
The main premise of the setting is that there is a huge diversity (In terms of number of species) of large mammal carnivores, specifically big cats, hyenas, bears and canines. I want to justify this scenario with some kind of plausible explanation, rather than "there just is".
The removal of humans is obviously going to help, and I never saw humans as being part of this age. I have my own idea, but I won't put it here; as I wouldn't want to start a discussion, which this site is obviously not for.
So, my question is; What scenario would be a plausible way to justify the appearance of all these large predator species?