WIKIMEDIA, CITRONSwordfish have a previously unrecognized oil gland near the base of the sword that connects via capillaries to pores on the skin, according to research published today (July 6) in the Journal of Experimental Biology. Marine biologist John Videler, emeritus professor at the Netherlands’ University of Groningen, and colleagues hypothesize that this gland produces an oily coating on the swordfish head, which—along with microscopic protrusions from the skin, called denticles—may reduce drag and boost swimming speeds.
“I find this quite fascinating,” ecologist Jens Krause of Berlin’s Humboldt University, who was not involved in the work, told The Scientist. Krause noted that the gland’s function has yet to be tested. “Much is really left as speculation. Nevertheless, I think it’s an interesting idea that deserves publication and will undoubtedly require testing.”
This paper was two decades in the making. In 1996, Videler performed magnetic resonance imaging (MRI) scans on two swordfish, which revealed the oil gland. In the early 2000s, study coauthor Roelant Snoek, who is now a marine biology consultant, discovered capillary networks connecting the gland to pores in the skin. Using electron microscopy, the researchers characterized the pores and observed denticles on the skin. When they experimentally heated the oil ...
