Columbia subject headings:
Harvard subject headings:
Herbivores--Ecology.
Herbivores--Size.
Mammals--Ecology
Mammals--Size.
Ungulates--Ecology.
Ungulates--Size.
Princeton subject headings:
Herbivores--Ecology.
Herbivores--Size.
Mammals--Ecology.
Mammals--Size.
Ungulates--Ecology.
Ungulates--Size.