actually...we do offer our bodies to others when we die.....to the real ruler of Earth...insects.
true, currently we don consciously offer ourself to others for food, or allow ourself to be eaten, and it is true that our live is no more important than theirs, BUT consider this, we humans are omnivorous animal, a high level one granted (this is debatable), but an animal nevertheless, and speaking as a species, we eat other species. just as carnivorous lions eat antelopes and deers (should we stop the savage lions from eating the delightfully cheerful and beautiful deer?) and herbivorous elephants eats sugarcanes. all this morality considerations comes in purely as a human invention and thus, it takes some getting used to to be applied to mother nature...yes?
and speaking of letting the animals eat us, we have been eaten before, by lions and saber tooth tigers, by remnants of the dinosaurs even if u will...when? many many millenias ago when we still cant tell peace from piss (even now i'm not so sure we do either...sadly).