Episode 206 – Boxer Crab: The Pom Pom Punch

“…and today we’re talking about yet another crustacean that packs a punch. More on that later.”

For a small crab with very little claws, there’s a ton of pressure on the ocean floor. Bigger fish can swallow you up like you were supposed to be in Nineveh. But when the challenge of survival is laid at one crab’s single-spiked feet, it picks up the gauntlet. The boxer crab climbs the steps of success and fights above his weight class using a clever trick his opponents don’t see coming. But using what you have at your disposal is the best way to win in Life, Death, and Taxonomy. 

 Description of the Boxer Crab

  • Tiny colorful crab 
  • Cream-colored carapace with eight legs striped with brown rings. The polygonal plates on the body are also lined with smoke on the water (deep purple).
  • There is a series of large brown-red plates on either side of its body that looks like big angry eyes.
  • Its coloration and pattern disruption allow it to blend into its sandy and coral-based environment pretty well. He wants the predators to think that he is leaving, he is leaving but the fighter still remains.
    • This is crucial because it’s not as well equipped to handle predators as most other crabs.
    • The boxer crab is pretty small and has a relatively thin and weak carapace.
    • Its front claws are small and underdeveloped, so it can’t really catch prey or fend off predators on its own.

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. 

  1. Goose
  2. French Hen
  3. Partridge
  4. Swan

Carapace Width

  • 0.5 inches (13 mm)
  • How many boxer crabs go into the height of the tallest professional boxer in history?
  • Hint: The tallest boxer is actually three boxers that all share the same height. Gogea Mitu of Romania in the 1930s, John Rankin fought only once in 1967 at 300 pounds, and Jim Cully fought in the 1940s but some sources say he was an inch or two shorter. 
  • 171 crabs. The tallest boxers were 7’4” (223.5 cm)


  • 20 m (66 ft)
  • How many boxer crab living depths go into the depth of the deepest permafrost in the world?
  • Hint: Permafrost is permanently frozen earth for at least two years. Permafrost can occur on land or under the ocean. Around 15% of land on earth is permafrost.
  • 50 crab depths. In Siberia, there’s an area of permafrost 1,000 meters (3,200 feet) down. 

Fast Facts About the Boxer Crab

  • Range: Lives in and around the Hawaiian Islands
  • Diet: Boxer crabs are omnivorous scavengers. 
    • They eat plant matter, dead animals, basically anything they can find. 
    • However, they don’t really hunt thanks to their underdeveloped claws.

Major Fact: The Pom Pom Punch

The boxer crab has a pair of colorful boxing gloves that provide a secret weapon against predators. Boxer crabs have pinchers that lack sufficient armor, so they can’t really use them to defend themselves or find food. 

Instead, they use their pincers to grab onto small sea anemone. These anemone are living creatures closely related to jellyfish. 

The crabs hold them all the time and only let go briefly to molt. They’ll use the anemones for two reasons. The first is that the tentacles of the anemone passively gather food particles that the crab scraps off and eats. 

Boxers also use the anemones for protection. When a predator approaches, they’ll get a swat from the crab. The anemones pack cnidocytes, which are stinging cells. They can deter larger predators and even kill smaller ones. 

The pom poms are a precious resource. If a crab is without one and can’t find one on their own, they may steal one from another crab. However, if a crab loses an anemone, they can rip the remaining one in half and it will regenerate, creating two new ones. If a crab loses both, they may still regrow from small pieces left in their claws. 

When crabs fight each other, they don’t use their pom poms. They will wave them around threateningly, but they ultimately use their legs to fight. We aren’t sure why. Some theories are that they aren’t effective, and don’t sting the crabs. The pom poms may be such a precious resource, that they don’t want to risk losing them.

If there are no anemones to be found, the crabs may use sponges or coral as a replacement. It’s unclear what the anemone gets out of the deal, though it may have to do with mobility. Moving around with the crab exposes it to more oxygen and food. 

If you were to be punched by a boxer crab, you may feel a very painful sting, followed by swelling, redness, and lesions that last for several weeks. 

Ending: So use what you can find, keep an eye out for predators, and wave those death poms like you just don’t care like the boxer crab here in Life, Death, and Taxonomy.