Lobsters vs. Crabs: What’s the Difference?

Discover the differences and similarities between lobsters and crabs and uncover some interesting facts about these shelled inhabitants of the sea.

Sep 14, 2023byCaitlin Ross
lobsters crabs how alike are they

When it comes to crustaceans, lobsters, and crabs seem to steal the spotlight. Both of these shelled creatures are well known for their unique appearances and snipping claws. But how alike are these two marine mysteries, and in which ways do they differ? Keep reading to explore the intricacies of brans and lobsters and discover what makes them special.


american lobster
Image credit: Science News Explores

First, crabs and lobsters look almost nothing alike! Aside from their sometimes reddish-brown color and hard exteriors, these two creatures are shaped completely differently – the crab sports a rounder body, while the lobster has a more elongated shape. However, there are still some other similarities between the two.

Both lobsters and crabs have a hard exoskeleton (their shells) that protects their soft and delicate inner bodies. Their shells act as a shield against predators too.

These creatures both have jointed legs and claws as well, which allow them to move quickly and with serious agility around their surroundings.

Finally, both crabs and lobsters have segmented bodies with different sections – their abdomen and a section known as the cephalothorax, which is their head and thorax fused together in one!


lobster habitat
Image credit: The Institute for Creation Research

While these creatures might look similar and share some physical attributes, their behaviors and preferences can tend to be quite different from one another.

For example, lobsters are typically found in ice-cold water and prefer rocky environments where there are plenty of holes and crevices for them to burrow deep inside. This is why the Atlantic Ocean is a prime spot for lobsters to lurk around.

Crabs, on the other hand, are much less fussy about where they make their bed. These creatures can be found in a wide array of different habitats, from the ocean to freshwater lakes, and you shouldn’t be surprised to find them on dry land in the sand or mud, either! Crabs love to burrow, making them happy beach dwellers.

Feeding Habits

crab feeding
Image credit: Shrimp and Snail Breeder

These scavenging critters are carnivorous by nature, but there are some pretty interesting differences in their overall feeding habits.

Lobsters are considered nocturnal hunters by marine scientists, which means that they choose the dark of the night to go on the prowl for their prey – fish, mollusks, and even other crustaceans. However, they’re also not averse to feasting on any other dead animals they might come across.

Meanwhile, crabs have a pretty diverse diet, and they’re less suspicious about how they get their meals. They feed on algae, small fish, invertebrates, and even plankton. Some types of crabs have herbivorous tendencies, too, widening their diet.

The most interesting thing about crabs’ mealtimes is that certain species use a filter-feeding technique to inhale their food quickly and easily through the water they’re passing through.

Defense Mechanisms

ghost crab
Image credit: Jeremy Janus Photography

Both crabs and lobsters sport some impressive coats of armor, but what else is there to know about their defense against predators?

First of all, crabs are known for using camouflage alongside their hard armor for protection. Some species have intricate colors and patterns on their shells that help them to blend into their surroundings with ease and hide away from predators. Their strong claws are another great source of protection – the coconut crab, in particular, is known for its weapons!

Interestingly, lobsters have a remarkable ability to regenerate lost limbs, much like lizards. This means that even if they’ve suffered an attack from an enemy, they’ll probably be just fine as long as they manage to escape.


lobster eggs
Image credit: The National Lobster Hatchery

Crabs and lobsters both go through some complex life cycles, and their reproduction process differs quite significantly.

For instance, where crabs carry their eggs internally, female lobsters carry theirs externally, attached to their abdomens.

When crab eggs hatch, they undergo a phase of metamorphosis, growing into juvenile crabs (which are tiny but fully formed) until they finally reach adulthood. Meanwhile, Lobster larvae go through several stages of molting before they mature.

Ecological Importance

lobster in cave
Image credit: DeeperBlue

Finally, it’s always important to consider the ecological impact of our animal and sea life because every creature has its own important role to play.

Lobsters play a vital role in maintaining the balance of our marine ecosystems. Since they’re considered predators, they do the important job of population control and ensure that the ocean doesn’t become overrun with smaller organisms. Without lobsters’ contribution (thanks to their feasting), the overall health of the habitat would suffer.

Crabs play an equally significant role in their respective ecosystem. They, like the lobster, help control the growth of smaller species, but they also serve as a source of food for many larger marine creatures.

Some species of crabs play deeper roles, too, such as the fiddler crab, which aerates the soil and promotes oxygenation through its digging and burrowing. This just goes to show that every tiny trait has a significant impact!

Caitlin Ross
byCaitlin Ross

Caitlin is an animal lover at heart with a passion for writing and sharing this love with the world. She’s a born and raised South African and grew up always surrounded by animals: more pets than she can count, and regularly adventuring with her family into the bush, where she feels most at peace with the wildlife in their natural habitat.