The Answer to Animal, Plant, Mineral, or Man-Made: #1

Image courtesy Emma Bueren

It’s the food straining antenna of a mole crab (Emerita spp.)!

Although it is sometimes called a sand flea, this crustacean has no interest in humans. It burrows in the sand of the intertidal swash zone to stay out of danger and to gather food. As a wave comes to shore, the mole crab uses its food-straining antenna to search the water for plankton to eat.

Mole crabs often molt and their shell casings can be found a little further up on the beach, near the wrack zone. To find a live mole crab, look for small “V” marks in the sand at the swash zone. Those tiny “V” marks are actually the feeder antennae, searching for food!

Congratulations to Amanda Kahn, for being the first to identify the creature and its antenna.

Runners up: Clifton Herrmann and Todd Ruston.

 The remains of a mole crab. Note the long circular structure of the secondary antenna, which is used to capture food. Image courtesy Emma Bueren