The horn of the Japanese rhinoceros beetle can grow to be two-thirds the length of the rest of its body. And size matters. The beetles battle with their horns to get access to female beetles. Biologists Doug Emlen and Erin McCullough, of The University of Montana, are looking into what regulates the size of this extra-large attribute.
Flora Lichtman is host of the podcast Every Little Thing. She’s a former Science Friday multimedia producer.