9 Fascinating Lobster Facts

Lobsters are a family of crustaceans that have inhabited the earth's seas for over 480 million years. Within the lobster family — called Nephropidae — there is a great deal of diversity in body size, claw size and shape, color, and eating habits. Lobsters can be found in all oceans of the world.

There are other crustaceans and crustacean families with "lobster" in their names, including spiny lobsters, slipper lobsters, and deep-sea lobsters. However, these are not as closely related to the Nephropidae family as their name suggests, and they are not considered "true lobsters" scientifically.

Long-lived and highly adapted to their local environments, lobsters are remarkable creatures. Here are a few fascinating facts about the lobster.

1. Lobsters Are More Closely Related to Insects Than Fish

Lobsters are invertebrates, which means they don't have a backbone. Their exoskeleton supports their body from the outside, like insects, which they are more closely related to. Both insects and lobsters are in the phylum Arthropoda.

Within Arthropoda, lobsters are part of the class Crustacea, which they share with crabs and shrimp.

2. Lobsters Live a Long Time

Lobsters have much longer lifespans than most crustaceans. A study of European lobsters found that the average lobster lifespan was 31 years for males and 54 years for females. The study also found some females that lived over 70 years.

Lobsters have indeterminate growth, which means they continually increase in size as they age, with maximum sizes unknown. Each time a lobster molts and regrows an exoskeleton, its size increases. The largest lobster ever caught measured three and a half feet long, weighed 44 pounds, and was estimated to be over 100 years old.

3. They Have Many Predators

Humans are far from the lobster's only predator. Seals like to eat lobster, as do cod, striped bass, and other fish. Eels are capable of slithering inside the rock crevices where lobsters like to hide. Crabs and shrimp eat very young lobster at high rates.

All lobsters live in the water full-time and are and benthic (that's the scientific term for bottom-dwelling). Most are nocturnal.

4. They Can Be Cannibalistic

When there is a high density of lobsters and not very many predators, lobsters will eat each other. This phenomenon has been observed in the Gulf of Maine, where overfishing (which reduces lobster predators like cod and halibut) has created a perfect environment for lobster cannibalism.

Under more typical circumstances, lobsters eat a variety of foods. They are generalist feeders, and their diet includes small live fish and mollusks, other bottom-living invertebrates like sponges, and plants like seagrasses and seaweed.

5. Lobsters Have Blue Blood

Lobster blood (called hemolymph) has molecules called hemocyanin that carry oxygen through the lobster's body. Hemocyanin contains copper, which gives the blood its blue coloring. Some other invertebrates, like snails and spiders, also have blue blood due to hemocyanin.

In contrast, humans and other vertebrates' blood contains iron-based hemoglobin molecules, which give the blood a red coloring.

6. They Come in Many Different Colors

Most lobsters are a combination of brown, grey, green, and blue. Lobster coloration generally corresponds to the local environment, which enables lobsters to camouflage themselves from predators.

Genetic factors can result in an atypical coloration, like a vivid blue, yellow, or white. These colorations are extremely rare; according to the Maine Lobstermen's Community Alliance, the odds of seeing a white lobster in the wild are one in 100 million. Lobsters can also be split-colored, with a different color on each side of their bodies.

No matter their natural coloring, all lobsters turn red when they are exposed to heat (via cooking or other means). That's because lobsters consume a red pigment called astanxanthin, which turns the skin beneath their shells a vivid red. Boiling water breaks down differently-colored proteins in the lobster's shell and reveals the red skin underneath.

7. Lobsters Communicate Through Their Urine

Strangely though it may sound, lobsters can communicate by peeing at one another. They release urine from the nephropores, located at the base of their antennae.

These urinary olfactory cues serve a number of different purposes related to hierarchy and mate selection. After male lobsters have established a hierarchy through fighting, they can recognize previous opponents and communicate their own social status through urinary signals. This signaling helps to maintain the established social order. Urinary signals are also a factor for female lobsters during mate selection.

8. They Have Eyes, But Their Antennae Provide More Information

Lobsters live in dark and murky environments on the sea floor. They have eyes on either side of their heads, but they mostly rely on their antennae to explore the world around them.

Most lobsters have three sets of antennae. The longer, larger ones are used to probe their local environment, and the two smaller sets of antennae detect chemical changes in the water around them. Their larger antennae are also used to distract and confuse predators, as well as maintain distance from them.

Lobsters also make sounds to scare or warn prey away by vibrating their exterior carapace.

9. Scientists Are Still Debating Whether Lobsters Feel Pain

Some scientists argue that lobsters lack the brain anatomy to feel pain as humans understand it, and that what we interpret as a lobster's pain experience (like thrashing in a pot of boiling water) is actually a painless reflex.

However, there is research to suggest that lobsters may be able to experience pain. A 2015 study found that crabs — which have similar nervous systems to lobsters — have a physiological stress response to electric shocks. The study also observed that, after being shocked, crabs appear to avoid areas associated with the shock. In combination, these two responses "[fulfill] the criteria expected of a pain experience," wrote the researchers. While equivalent studies have not been conducted on lobsters, we know that lobsters demonstrate stress responses like thrashing and trying to exit the pot when they are boiled alive.

Citing this research, Switzerland passed a law in 2018 requiring lobsters to be stunned before they are boiled for human consumption.