Star-Nosed Moles, Electric Eels, and Other Tales of Evolution’s Mysteries Solved

Kenneth Catania Presents the First Porter Book Club Lecture

BY ELISA GUMA, NIMH

“Nature was my first classroom,” said Kenneth Catania to an engaged group of about fifty people gathered for the inaugural Porter Book Club event. Catania is the Stevenson Professor in the Department of Biological Sciences at Vanderbilt University (Nashville, Tennessee), and presented his book Great Adaptations: Star-Nosed Moles, Electric Eels, and Other Tales of Evolution’s Mysteries Solved, to NIH staff on March 10. He shared a personal account of the unexpected and fascinating discoveries made during a career spent investigating nature’s most mysterious animals.

Catania’s journey to becoming a biologist and neuroscientist started as a young boy growing up in Columbia, Maryland, where he collected interesting critters inhabiting the surrounding forests, lakes, and streams. And it was there, in that natural classroom, where he first encountered the elusive star-nosed mole. The unfortunate creature was dead, perhaps forced out of its habitat due to nearby developments, but it made a lasting impression on young Catania.

Years later, that encounter would help him land his first research internship. As an undergraduate student interning at the National Zoo in Washington, D.C., Catania was brought on to capture and bring back wild star-nosed moles. A team of researchers there wanted to study whether the mole’s curious looking nose, comprising 22 sensory appendages resembling a star, could detect electric fields. While these creatures are not endangered, they are extremely hard to find because they live underground in wetlands, usually under mud and dense vegetation.

Ready for the challenge, young Catania set out into the northern Pennsylvania wilderness in a van (in which he slept) with some traps, a map, and some jars of earthworms for baiting. He came upon an ecologically rich wetland surrounded by foothills where accumulated decaying vegetation and moist soil had allowed a huge diversity of invertebrates and other animals to thrive. Eventually, he caught five or six moles; the trip was considered a huge success! Back at the zoo, however, he didn’t find evidence for an electric sense—a mole’s nose was not, in fact, an electroreceptor. He surmised it must serve a different purpose.

Despite that early setback, Catania eventually cracked the case of the mole’s nose in graduate school. It turns out that the pink, fleshy tentacles surrounding the small mammal’s nose were exquisitely sensitive sensory organs. Compared to the human hand, which has 17,000 touch fibers, the star-nosed mole’s snout has an astounding 100,000, making it one of the most densely innervated skin surfaces of any mammal. This sensory organ enables the mole to navigate through underground tunnels and forage for food at unprecedented speeds, sometimes eating five separate prey items in a single second.

Through his experience with the star-nosed mole, Catania got a taste for solving biological mysteries and studying extreme adaptations in the animal kingdom that reveal new insights into how life evolved. He learned the benefits and challenges of tackling questions (and going on adventures) that few had previously considered. He has since applied those skills to learning more about other animals such as electric eels, tentacled snakes, water shrews, and parasitoids. Such creatures have advanced the field of science in unique ways. For example, the electric eel inspired Italian physicist Alessandro Volta to invent the battery in 1800 and allowed scientists to first identify acetylcholine receptors, which enable skeletal muscle contraction.

Catania also shared his process of discovery, which has gone hand-in-hand with failure in his own research. “As a rough rule of thumb, one in six ideas work and the rest fail,” he said, adding that he encourages young scientists to get comfortable with failure. “Learn not to get too attached to any one idea, and then move on quickly from those failures.”

Elisa Guma, a Postdoctoral Fellow in the National Institute of Mental Health, is studying how sex and sex chromosome number can affect brain anatomy in both humans and mice in hopes of understanding how sex differences in the brain may have evolved across species. Outside of work she enjoys doing ceramics, rock climbing, and getting outdoors for a hike.