Why This Spider Has a Cartoonish Butt

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Pokémon may not be real, but this spider could be the next best thing.

While conducting research in the jungles of Honduras, National Geographic explorer Jonathan Kolby stumbled across the closest nature has ever come to creating the cartoon’s beloved Pikachu.

On the rear abdomen of the arrow-shaped micrathena, Micrathena sagittata, is a bright yellow marking with two long rear spikes that end with black tips. Slightly more menacing than the mild-mannered cartoon is another row of spikes, at the bottom of the Pikachu-like structure. The rest of the spider’s body is a bright reddish color, almost resembling an ant.

When Kolby first noticed the micrathena at his research site in Cusuco National Park, the spider’s cartoonish feature was the first thing he noticed. ( Read more about Kolby’s work to save frogs in Honduras.)

“The exceptional spines protruding from its rear are what immediately caught my attention!” he said in an email.

While this trip to Honduras was the first time the amphibian specialist has seen this spider species, arrow-shaped micrathenas can actually be found throughout North America and are even widespread in the U.S. They can be hard to spot though-these spiders are small. Females, usually twice the size of males, grow to only a centimeter (legs included.)

The bright yellow backs, which only form on females, usually tend to attract attention. Scientists believe this may help the spider prey on insects. A 2002 study published in the journal Ecological Entomology studied a similarly colored black and yellow Australian spider and found that its bright abdomen may help attract prey.

Using a black marker, the researchers “erased” the spiders’ bright yellow color. The spiders whose colors had been thus muted were on average less successful at catching prey. Like arrow-shaped micrathenas, the Australian spiders are “sit-and-wait” predators that ensnare prey in large webs. ( Watch these baby spiders eat their mothers alive.)

While the bright yellow color may attract prey, the spider’s spikes ward off predators. Kolby explained that the spikes may make it difficult for animals like birds to swallow the small creatures.

When Kolby found the spider in Honduras, it was resting in a web that was suspended above the ground. He took the photo and left it in peace, content to not catch them all.