Move over, Lady Gaga—in the wild, plenty of animals are natural accessorizers.
In a recent study, Stevens and colleague Graeme Ruxton reviewed literature on animals that adorn themselves—like the decorator crab—and discovered that bling may serve a variety of functions, from camouflage to communication.
"The most common reason to decorate is to avoid predators," said Stevens, whose study was published June 3 in the journal Royal Society Biology Letters.
Others include protection from sunlight and "cosmetics" to appear more attractive to mates.
Take a look at some of nature's best-dressed animals. (Also see "5 Animals That Look Like Lady Gaga.")
A number of crab species belonging to the family Majoidea dress for success, using materials from their environment to hide from or ward off predators.
The crabs' shells are covered with Velcro-like hairs that help them stick seaweed, sponges, anemones, corals, and other objects to their backs. This can help the crab blend into the background or actually look like another object—a strategy ecologists call masquerading.
Watch a video about another species of crab that uses a sea urchin as a shield.
Other times, crabs choose specific items with which to decorate that have a pungent smell or contain noxious chemicals, making them repugnant to predators.
The larvae of many caddisfly species (insects of the order Trichoptera) make hard cases out of whatever material they find in the environment. The larvae produce silk to bind the materials into a sturdy armor, which keeps them safe from predators. (See "Photos: Masters of Disguise—Amazing Insect Camouflage.")
Even when feeding or moving around, most of the larva remains hidden inside the case. The elaborate shields may also keep larvae secured in their rapidly moving freshwater habitat.
These pig relatives enjoy a good wallow in a muddy pool—and then end up "wearing" the dried mud. Scientists believe such mud baths help regulate their body temperatures, reduce parasites, and disinfect wounds.
Study co-author Stevens says some assassin bugs in the family Reduviidae carry around the dead carcasses of their ant prey as a "backpack" to protect them from predators.
It works: Backpack-wearing assassin bugs are less likely to be eaten by jumping spiders than those without this macabre accessory, research has shown. That's because the predatory spiders notice the mound of dead ants but not the tasty bug hiding underneath.
Some birds add material to their feathers to change their appearance, much like makeup.
Mostly white-feathered bearded vultures (Gypaetus barbatus) rub their heads, necks, and bottoms in iron-rich soil, which gives them a reddish-brown hue.
Older and socially dominant birds have the most color, so it's likely that it functions as a status symbol. (Related: "Flamingos Apply 'Makeup' to Impress Mates.")
It's also possible that the birds' colorful add-ons are medicinal, providing antioxidants and safety against potentially harmful bacteria.
How'd you like to wear your poop? The larvae of lacewing insects in the family Chrysopidae often cover themselves with shields of dead skin, their own droppings, and other materials. These coverings seem to offer both camouflage and predator defense. (Related: "A 110-Million-Year-Old Trash Collector.")
For instance, green lacewing larvae, which eat aphids, transfer a waxy wool substance from their prey's bodies onto their own. This embellishment protects the lacewings from protective ants that tend the aphids. In experiments, if the lacewings' shields are removed, the ants throw the intruders out.
Moral of the story: Always dress to kill.