What?! Weirdest Animal Stories of 2013

Butterflies in the Amazon have been observed flocking onto the heads of turtles to drink their tears, which provide the animals with a vital source of the mineral sodium.

(Image credit: Jeff Cremer / Perunature.com)

Cute animals are an Internet genre of their own. But sometimes, Mother Nature's creations are downright weird.

The past year had its share of bizarre animal discoveries, from butterflies that feast on the tears of turtles to a two-headed shark fetus. Speaking of shark fetuses, they can sense predators even while they're still in their egg cases. Like we said: weird.

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The Nopoli rock-climbing goby (Sicyopterus stimpsoni), found throughout Hawaii, has a strange talent: It can climb its way up waterfalls 300 feet (100 meters) tall, using an ancillary mouth sucker. To put that in perspective: If the rock-climbing goby were human, the equivalent would be running a marathon vertically, against running water, Clemson University biomechanist Richard Blob told LiveScience.

While some sharks give live birth, others deposit egg cases called mermaid's purses in the water. The shark fetuses in these egg cases are relatively defenseless, but the fetuses of bamboo sharks do have one protective trick up their sleeves. When a predator is nearby, the fetuses can detect its electrical field and freeze, so the predator is less likely to see them. [See Video & Images of Developing Bamboo Sharks]

A March 2013 study revealed that bat-eating spiders live on every continent except Antarctica. After a web-building spider species (Argiope savignyi) and a terrifying tarantula species (Poecilotheria rufilata) were found to kill and eat small bats, researchers got interested in how common it was for spiders to eat bats. They combed through 100 years of scientific reports and observations and found 52 instances worldwide. Most of the time, spiders prey on bats in the tropics, particularly the toasty regions of North and South America.

Butterflies congregate on yellow-spotted river turtles to drink their tears, researchers said in September. The motivation? Minerals. Salt is scarce in the western Amazon, and herbivores like butterflies (and bees, which have also been seen supping on turtle tears) struggle to get enough. Other than temporarily obstructing the turtles' vision, the tear-drinking likely has little effect on the reptiles.

The orchid mantis, *Hymenopus coronatus* (a juvenile male, shown here), which resembles a flower, takes on this appearance in order to lure in prey, researchers say. In fact, orchid mantises are even better at drawing in insects than some actual blossoms; they not only look like flowers, but they also beat the petally beauties at their own game, scientists added.

The orchid mantis is like several other insects in that it mimics the look of a harmless plant. But while most mimics disguise themselves from predators, the orchid mantis is a predator. And its flowery look actually attracts its prey, particularly pollinators like bees and butterflies. The mantis is the only animal in the world known to mimic a flower blossom to attract prey, researchers reported in November 2013.

Stephanie Pappas is a contributing writer for Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor's degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz.