Tag: 上海贵族宝贝XI

first_imgHermit crabs have a pretty good thing going. They make their home in discarded gastropod shells, and when they outgrow it, they just hop into a bigger one. This affords the crab protection from ocean predators, but some species have taken this a step further and adorn their shells with anemones. The two species have formed a symbiotic relationship. So, what happens when the crab needs to switch shells? That’s when it gets really cool.Having sea anemones living on its shell gives the crab an active defense against predators. All it has to do is retreat into the shell and let the stinging tentacles of the anemone ward off an attacker. Riding around on the crab’s shell is advantageous for the anemones too. The two animals share food, and being mobile allows an anemone to disperse its offspring more efficiently.When the time comes to swap shells, the hermit crab brings its old shell close and hops into the new one. It won’t leave the anemones behind, though. The video above shows the process of moving the anemones to the new shell. The crab tugs on the anemone and peels it off the old shell. Then it places the anemone on the new shell and it attaches itself with its adhesive foot, known as a basal disc. It will only detach from a shell when coaxed by a hermit crab.The species of hermit crabs that do this are toward the larger end of the scale, but are still only a few inches across. They’ve got room for between two and three small anemones at most. That’s still enough to scare away many of the crabs natural predators. Symbiosis is fascinating.last_img read more