I'm well aware of cases in evolution where mainly carnivorous animals become primarily herbivores (bears, primates, bats, etc.), but has the reverse ever happened? Has there ever been an instance in evolution of herivores evolving into carnivores?

Haven't all carnivores evolved from herbivores if one goes far enough back?

I can't think of any more-concrete examples but the ancestor of the pangolin (http://en.wikipedia.org/wiki/Pangolin) called Eomanis is thought to have been mainly a herbivore that accidentally ingested insects, whereas extant pangolins only eat ants and termites.

Last edited by Owen Jones (22nd Nov 2012 11:29:45)

I don't think so David. The ancestral condition of most vertebrate groups is carnivory of some description and indeed for most invertebrates. Once you get right down to filtering out plankton where you will be getting phyotplankton and zoo plankton I guess you oculd call this something like herbivory, but it's more like omnivory and eating other organims whole. While we're obviously blessed with plenty of berbivores in terms of insects and grazing mammals, it's generally secondary.

Few fish eat plants for example and eat other fish, or small invertebrates (or plankton). Plenty of birds eat seeds but most eat insects etc. and there's barely a reptile or amphibian that's not a carnivore.

interesting and thanks - I sit corrected!