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Hermit crabs have odd ways of preventing theft and finding new homes…

Calliactis and Dardanus 001.JPG
large red hermit crab with shell/H. Zell
(CC BY-SA 3.0)

The hermit crabs learned to move into the shells of dead crustaceans, and their well-being depends on that movable property. Recent research suggests that they have made some unusual efforts, as species, to hang onto the desirable shells:

Over the course of evolution, penis size has been subject to female choice and competition with male rivals. In a study published today (January 16) in Royal Society Open Science, Mark Laidre, a biologist at Dartmouth College, introduces a new idea: that larger penises help animals keep hold of precious resources. He compared hundreds of specimens of nine related species of hermit crab and showed that crustaceans that have more valuable shells have longer sexual tubes, helping them keep a grip on their homes while they extend their reproductive organs toward a mate. “It is a relatively novel way of thinking about the evolution of penis size,” says Morgan Kelly, a biologist at Louisiana State University who was not involved in the work. Abby Olena, “Larger Hermit Crab Penises May Prevent Shell Theft” at The Scientist

Hernit crabs do put a lot into their mobile homes:

These animals can whittle their shells and secrete erosive chemicals, allowing them to create a smooth and expansive interior. These refurbished homes give them space to grow and may even provide room for egg storage—making the shells extremely valuable. They are, in other words, not something that you’d like to leave—even temporarily—which many hermit crabs have to do to mate. But what if you could have a large enough sexual organ to reproduce without exiting your shell, which rivals may steal? Jake Buehlere, “Male hermit crabs evolved larger sex organs to avoid losing homes” at National Geographic

Finding new homes?

See also: Researchers: Some Life Forms Don’t Grow Old Or Lose Fertility, Challenging An Assumption About Evolution (they live longer too)

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Did anyone say that hermit crabs do not kill snails and take their shells? No ET
Well, YOU didn’t seem to understand that otherwise you would not have even brought it up.
They also kill them in the wild to take the shells. But more on topic, the barnacle, another crustacean, has the longest penis relative to body size of any animal. So when you see some guy wearing a T-shirt that says “Hung Like a Barnacle”, they are bragging. Ed George
Well, YOU didn't seem to understand that otherwise you would not have even brought it up. ET
Aquariums are artificial environments, Ed.
Thank you, Captain Obvious. :) Ed George
Aquariums are artificial environments, Ed. ET
For us in the aquarium hobby they also have a nasty habit of evicting (ie, eating) snails if they desire their shells. Does a number on your clean-up crew. Ed George

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