Death of a Sea Monster

Old bones have many tales to tell. The fossilized skeleton of any prehistoric creature contains clues about that animal's evolution, as well as the world around it and—if we're lucky—what caused its death. One such skeleton is at the center of the National Geographic Channel program Death of a Sea Monster.

The documentary's titular sea monster is a large, nearly-complete ichthyosaur skeleton excavated by paleontologist Jørn Hurum and his team from the approximately 147-million-year-old strata of Svalbard. According to the documentary, it is the first discovery of its kind made at this Arctic site, but this shark-shaped marine reptile is not the first Svalbard fossil to enjoy a little fame. In 2008, Hurum made news with the discovery of a short-necked, large-mouthed pliosaur informally dubbed "The Monster." Then, in a 2009 media blitz that included a History Channel documentary, Hurum announced the discovery of a second, even bigger pliosaur from the same site. You may know the second creature by it's B-movie moniker "Predator X" (which, appropriately enough, has inspired a made-for-TV horror movie). Neither the Monster nor Predator X has been fully described, and they are referred to only as pliosaurs in the National Geographic Channel program.

(A brief note: Hurum was involved in the promotion of the fossil primate Darwinius masillae ("Ida") in 2009, and I criticized him and the media company he worked with for the sensationalist claims about that fossil.)

In the new show, though, it is the ichthyosaur's time to shine. After the arduous task of excavating the ichthyosaur skeleton from the cold Svalbard rock, transporting it, and cleaning it up, Hurum and colleagues discover that a large chunk was taken out of this animal near its tail. There also appeared to be large bite marks on the bones, and there was only one kind creature in the ecosystem large enough to cause such devastation. No prizes for guessing which.

But the "sea monster" angle is only a hook to get at a bigger mystery surrounding the lives of the many marine reptiles Hurum and his team have found. Despite an abundance of large predators at Svalbard—primarily ichthyosaurs, long-necked plesiosaurs and short-necked pliosaurs—hardly any fish remains have been found. Instead, there are abundant fossils of coil-shelled cephalopods called ammonites, extinct cousins of squid and nautilus. Might ammonites, rather than fish, have been the chief food source of many of the Jurassic marine reptiles? This question ties the disparate threads of the show together.

Other fossil tidbits restore important details of the prehistoric environment. The deposits at Svlabard do not indicate a warm Jurassic sea, but a relatively cold ocean seemingly devoid of fish, and there appears to be some evidence of methane seeps along the ancient seabottom. These sites are exactly what they sound like—patches along the sea floor where methane trickles out—but, as we know them today, these sites also support communities of strange, deep-sea creatures similar to those that inhabit the fringes of hot hydrothermal vents. Among the ruins of these seeps one paleontologist even uncovers what is interpreted as part of a squid that reached Kraken-like proportions, though this suggestion remains unconfirmed by the show's close.

"Death of a Sea Monster" is a close look at the harsh conditions paleontologists face while working at Svalbard, and also offers a sneak peek at discoveries that will hopefully be described in the scientific literature someday soon. If the hypotheses presented in the show are correct, the Svalbard deposits could represent a unique prehistoric ecosystem in which giant marine predators thrived on an alternative food source. Throughout the program I repeatedly thought to myself, "I hope that they're writing a paper on that." I find it frustrating when documentary programs are used as platforms to present scientific discoveries that may not be published for many years afterward. Considering the circumstances, though, the National Geographic Channel program is a well-constructed preview of what could be some remarkable fossil finds. In all, Death of a Sea Monster is a compelling look at how paleontologists start with scattered fossils in the field and wind up with a vision of a long-lost ecosystem.

Death of a Sea Monster will air Saturday, April 9 at 9 PM ET/PT on the National Geographic Channel

Riley Black | | READ MORE

Riley Black is the author of The Last Days of the Dinosaurs and many other books. She is a science correspondent for Smithsonian magazine covering fossils and natural history, and she writes about the prehistoric past for a variety of publications.