For years, marine biologists have puzzled over what the mysterious vampire squid eats.
The vampire squid (Vampyroteuthis infernalis) is a small, deep-sea cephalopod found throughout the temperate and tropical oceans of the world.
It's easy to imagine the vampire squid as a nightmarish predator. It lurks in the eternal midnight of the deep sea, has a dark red body, huge blue eyes, and a cloak-like web that stretches between its eight arms. Its latin name, Vampyroteuthis infernalis, literally means "vampire squid from Hell")
In reality, the vampire squid is a soft-bodied, passive creature, about the size, shape, and color of a football. A "living fossil," it inhabits the deep waters of all the world's ocean basins at depths where there is almost no oxygen, but also relatively few predators.
A few previous researchers have caught vampire squids in nets, hauled them up to the surface, and tried to figure out what they ate by examining the contents of their stomachs. The results were generally inconclusive. The stomachs typically contained bits and pieces of tiny, shrimp-like animals, microscopic algae, and lots of slimy goo.
Poop and snot
In a recent article in the Proceedings of the Royal Society B: Biological Sciences, MBARI scientists Postdoctoral Fellow Henk-Jan Hoving and Senior Scientist Bruce Robison, show that vampire squids eat mostly "marine snow"—a mixture of dead bodies, poop, and snot.
The dead bodies are the remains of microscopic algae and animals that live in the waters farther up in the ocean, but sink down into the depths after they die. The poop consists of fecal pellets from small, shrimp-like animals such as copepods or krill.
The snot is mostly debris from gelatinous animals called larvaceans, which filter and consume marine snow using mucus nets.