The deeper you go, the bigger they get. This is an adage that applies to much of the life eking out an existence in the crushing depths of our oceans. Near the surface, tiny crabs are terrified of larger predators. In the deep, 13-foot-wide giant spider crabs are usually the predators themselves.
Perhaps the most infamous example of this deep-sea gigantism is the giant squid, capable of attaining lengths of over 40 feet and possibly even longer should it stretch out its tremendous tentacles. Giant isopods, giant jellyfish, even giant amoebas, the list goes on. But just what is driving this varied cast to get so extravagantly sized?
Are Bigger Animals More Efficient?
One potential explanation is that the deep sea is very dark, cold, and far from the surface where most other life lives. As a result, food, usually in the form of falling bits of detritus called marine snow, is sparse. It pays to be efficient with your scarce energy, and as a general trend, bigger critters tend to be more efficient.
