This paper investigates whether body size-related constraints on home-
range resource harvesting could lead to coexistence between interspeci
fic competitors of different body size under conditions of complete ni
che overlap. With this objective, I analyzed the influence of body siz
e on induced and sustainable resource limitation and its implications
on the interaction between an individual and a fixed biomass of larger
competitors in a four-dimensional space, consisting of two spatial di
mensions describing competitor home range, resource availability, and
time. It was shown that body size-related spatiotemporal constraints o
n home-range resource harvesting, trophic optimization, and relativity
of resource availability determine absolute and relative amounts of u
nused home-range resources, restricting the influence of resource limi
tation induced by an individual to a definite size distance around its
size. It was therefore concluded that: (1) when competition occurs as
ymmetrically with a superiority of large animals, size differences alo
ne could allow coexistence, independently of any kind of resource part
itioning; and (2) superiority of large animals should result from the
resource density control that a larger competitor imposes on the small
er one whenever size differences for stable coexistence occur. Existin
g evidence of an inefficiency in home-range resource exploitation seem
s large enough to suggest a view of guilds based on a hierarchy of inc
lusive home ranges.