Hermit Crabs

Hermit Crabs

These crustaceans can’t grow their own carapace, so to protect their soft abdomens from enemies, they walk around with abandoned shells. Though hermit crabs use what they can find, including glass and cans, some have specific preferences. (The Pagurus samuelis, for instance, favors shells from black turban snails.) Crabs need bigger shells as they grow and they often fight each other for armor. As competitive as they may be, hermit crabs don’t harm snails.  

(Photo: Richard du Toit/Getty Images)

Birds

Birds

A particularly creative wren was once reported to have fashioned a nest built completely out of office supplies, including thumbtacks, paper clips, and rubber bands. Chances are if you leave a small pile of twigs, leaves, and dry grass in your backyard, a bird will pick it up to make a nest. Of course, if you want to attract birds to your backyard, keep it organic and pesticide free—just in case they eat the materials there. 

(Photo: Celia Hueck/Getty Images)

Burrowing Owls

Burrowing Owls

Unlike their tree-dwelling relatives, burrowing owls live underground. They’re able to dig their own holes, but the birds will just as happily take burrows abandoned by prairie dogs or other critters. They recycle when decorating too. Burrowing owls carpet their nests with dung. The muck attracts fellow recyclers that happen to be the owls’ favorite snacks: dung beetles.

(Photo: Anderson Neomar Gomes/Getty Images)

Dung Beetles

Dung Beetles

As their name suggests, dung beetles have an affinity for excrement. They roll up droppings into balls to eat, bury them underground, and lay eggs on them. Scientists even suspect that dung beetles help reduce global warming—their digging action in cow manure lessens the methane gas released into the air. Though the significance of their impact on climate change is still up for debate, they’re nevertheless some of nature’s greatest recyclers. As scientist Bruce E. Gill said, “If it weren’t for dung beetles, we’d be up to our eyeballs in you-know-what.”

(Photo: Marco Isler/Getty Images)

Octopuses

Octopuses

In 2009, scientists in Indonesia observed a peculiar behavior in octopuses: The eight-armed mollusks were tiptoeing across the seafloor carrying coconut shells under their bodies. This astonished the researchers. Unlike hermit crabs, the critters weren’t collecting the coconuts just for armor; they were transporting the shells for later use as shelter, signaling their ability to plan ahead. This trait makes octopuses the first animals without backbones that use tools.

(Photo: A. Martin/Getty Images)