What caused the Pleistocene Mass Extinction?

[parvez]

I read somewhere entire northern hemisphere had plenty of herbivores in Pleistocene. Thus carnivores too must have flourished. But that cycle or rhythm must have shifted to southern hemisphere. That may be the reason why southern hemisphere with some exceptions has plenty of floral and faunal diversity. Plants must have died first due to change of particular cycle or rhythm followed by mass extinction of animals. Or perhaps it may be due to change in earth's magnetic field. No one knows the true reason. Sorry if I spoiled the discussion. Reply