Squat lobsters

There are over 900 squat lobster species found throughout the ocean, except in cold Arctic and Antarctic waters. They typically live on the floors of seamounts, canyons, and hydrothermal vents. Though they look like lobsters, squat lobsters are crabs and are closely related to hermit and porcelain crabs.

The behavior of our local squat lobsters changes dramatically based on the oxygen content of the water. They can live in low oxygen waters where very few other organisms are able to survive. Munida quadrispina squat lobsters are sedentary, non-territorial, and docile towards one another in low oxygen waters, even when so densely packed that they’re touching. In water with normal oxygen levels, where there also happen to be many other invertebrates and also fish, their bodies are never touching and they are aggressive and territorial towards one another. They occupy cracks and crevices, and if other squat lobsters try to enter, they will grab or pinch them so aggressively that one may lose their claws.

Munida quadrispina squat lobsters grab zooplankton from the water with their claws to bring to their mouth. They will also pick up detritus or feed on carcasses. These squat lobsters are smaller than Dungeness crabs and when they encounter one another at a large carcass, the squat lobsters rely on the larger and stronger dungeness crabs to break through tough tissue so they can enter the body cavity.