Ruminating mammals include cattle , goats , sheep , giraffes , bison , yaks , water buffalo , deer , camels , alpacas , llamas , wildebeest , antelope , pronghorn , and nilgai . Ruminating mammals include cattle , goats , sheep , giraffes , bison , moose , elk , yaks , water buffalo , deer , camels , alpacas , llamas , wildebeest , antelope , pronghorn , and nilgai .