If by predator you mean any animal...there are numerous single celled animals that prey on and consume other single celled animals.
The smallest element known to man is Hydrogen (H).
Bacteria cells. They are the smallest living thing on Earth (known to man).
When we "look" at the smallest things known, we must consider the group of subatomic particles. The tiniest units of matter exist in this quantum mechanical world. As we're still sorting out some things here, it may be hard to be more specific. But let's nominate the electron neutrino, a fundamental particle, as the least massive of the particles in that group.
The smallest unit of life is known as an atom!
an atom
amoeba
yes it is actually the smallest known to man
predator
Musk Turtle
Man. The worst predator there is
carnivourous ant :P
Man is the only predator of sharks.
Of course these beautiful, intelligent birds have a predator - man...
man
Great white sharks have no predators exept for man.
The atom is the smallest known particle.
The Siberian tiger is an apex predator and has no predators except man.