Some explanation here.
Omnivore is a scifi novel
by Piers Anthony. It
describes, through the
eyes of a small team of
humans, a planet whose
life has evolved from fungi.
The manta lifeform is the
top predator --here
protecting one of the
earthmen, Veg, from a
carnivore.
The novel is heavily
didactic and the omnivore
is actually Man, i.e., the
most destructive of all
species.
More on the subject here.
