Table 1. Study species pairings based on body mass and feeding strategy. Emboldened pairs used in extant ruminant and hindgut paired t-test comparison.

	Approximate Mass*	Feeding Strategy	Foregut Fermenters	Hindgut Fermenters
	~3kg	Browser	Tragulus javanicus (lesser mouse deer)	Dendrohyrax dorsalis (tree hyrax)
	~6kg	Browser	Cephalophus monticolor (blue duiker)	Eurohippus parvalus † Hyracotherium sp.†
	~25kg	Browser	Cephalophus ogilbly (Ogilbly's duiker)	Mesohippus sp.† Mesohippus sp.†
	~60kg	Mixed Feeder	Dama dama (fallow deer)	Merychippus sp.† Merychippus insignis †
	~75kg	Browser	Odocoileus virginianus (white- tailed deer)	Kalobatippus sp.†
	~120kg	Grazer	Damaliscus lunatus (tsessabe)	Calippus martini†
	~250kg	Grazer	Tragelaphus strepsiceros (greater kudu) Okapia johnstoni (okapi)	Tapiris bairdii (Baird's tapir) Tapiris terrestris (lowland tapir)
	~250kg	Browser	Connochaetes taurinus (blue wildebeest)	Equus burchelli (common zebra)
	~450kg	Grazer	Bos taurus (domestic cow)	Equus caballus (domestic horse)
	~800kg	Browser	Giraffa camelopardalis (giraffe)	Dicerorhinus sumatrensis (Sumatran rhino)