PBS - Triumph of Life: The Eternal Arms Race (2009)

Since the dawn of life, an evolutionary arms race has imbued predator and prey with ever more sophisticated weaponry. Teeth and jaws are merely the low-tech side of the struggle. Bats have evolved sonar, and moths have devised a way to jam it; squid create smoke screens, caterpillars concoct poisons, and the race escalates from eon to eon.