One of the coolest aspects of doing research on the water is the “wild” aspect of it all—anything could happen on a given day, and there is always the potential for new discoveries. Sometimes discoveries are made after years of data analysis and attention to an issue, while other times nature hands it over to you in the heat of the moment….literally.
What would you do if a tiger shark vomited partially digested food on you?
Our research team was faced with this very question in November 2010 during a normal day of shark research in the Florida Keys. While taking measurements and blood samples on a sub-adult female tiger shark, I noticed a trickling of greenish, oily liquid coming from the mouth of the tiger shark. A few seconds later, a huge clump of feathers joined the river of bile and stomach acid. I sat there next to the shark, and couldn’t help but smile, knowing what this neat little observation meant.
These are the moments that we savor as scientists—the ones when nature decides to give you a little hint, a “tip” so to speak. We finished the work up of the animal, attached a satellite tag to her, and sent her on her way. Meanwhile, we bagged up the feathers and kept them on ice. And while tiger sharks are known to have a broad diet which indeed includes birds, we knew an identification of the specimen was needed before we could make any conclusions.
Partially digested remains of an American Coot, as vomited by a female tiger shark.
I spent the entire next morning calling bird experts at NOAA, Miami Museum of Science and the Florida Keys Bird Sanctuary. Upon making a few calls and emails, the story got juicier and juicier. I soon found out that there was a recent massive bird die-off, where hundreds of turkey vultures somehow ended up floating dead in Biscayne Bay and the middle Florida Keys—an area right in the “wheelhouse” of our tiger sharks. With the help of Tom Jackson at NOAA, we positively identified the specimen as an American Coot, a terrestrial bird species which is found in marshes throughout the middle of North America. It wasn’t a marine bird, and hardly a local species.
How did it end up in the tiger shark’s stomach?
The tiger shark’s menu is large and diverse. Photo by Austin Gallagher
We concluded that since there was a massive input of new potential prey items, the tiger sharks responded and took advantage. In fact, results from our satellite tagged individual showed that it spent a considerable time on the surface near Biscayne Bay after we released it, potentially continuing to feed on the floating mass of birds.
While tiger sharks are known to consume birds, such a scavenging event has rarely been described in the Atlantic, allowing us to publish a short note in the journal Florida Scientist. Since that day, we have seen tiger sharks puke up some other interesting food items. And while this was just one small observation, our finding is another piece of the puzzle to understanding these complex predators. Nature sometimes moves in mysterious way, and the infamous “Tiger Bird” episode proves just that.
If any other sharks want to puke on us, we are ready and willing.
-Austin Gallagher
PhD Student, Research Assistant
RJ Dunlap Marine Conservation Program
Abess Center for Ecosystem Science and Policy
www.rjd.miami.edu
www.austingallagher.com
agallagher@rsmas.miami.edu