This crab ripped off its pants for the camera…

nudecrab

Twitter informs me there’s something called #NationalSendaNudeDay. Am I doing this right?

(Maybe the Post Office and/or Hotmail are desperate to justify their existence.)

Anyway… here is a recently molted crab we found during an early morning intertidal zone hike with students adventure travelers during our seminar adventure tour in the Andamans near Wandoor in 2015.

The one on the right is basically nude. A nude crab. And on the left… crab pants.

For a bit of background on why a crab would take off its pants, let’s turn to NOAA:

Crabs (and other crustaceans) cannot grow in a linear fashion like most animals. Because they have a hard outer shell (the exoskeleton) that does not grow, they must shed their shells, a process called molting. Just as we outgrow our clothing, crabs outgrow their shells. Prior to molting, a crab reabsorbs some of the calcium carbonate from the old exoskeleton, then secretes enzymes to separate the old shell from the underlying skin (or epidermis). Then, the epidermis secretes a new, soft, paper-like shell beneath the old one. This process can take several weeks.

A day before molting, the crab starts to absorb seawater, and begins to swell up like a balloon. This helps to expand the old shell and causes it to come apart at a special seam that runs around the body. The carapace then opens up like a lid. The crab extracts itself from its old shell by pushing and compressing all of its appendages repeatedly. First it backs out, then pulls out its hind legs, then its front legs, and finally comes completely out of the old shell. This process takes about 15 minutes.

Note: It pulls this off while leaving the original shell more or less intact. That’d be like getting out of a wedding saari without actually undoing any fold or wrap and leaving the hole thing standing. Could you do that, Ishani?

Tags: , , , , , , , ,