SOLOMONS, Md. – The extinct megatooth shark Otodus megalodon (aka “megalodon”) was the largest shark that ever lived, reaching up to 65 feet in total body length. Megalodon is well known for its large, evenly serrated teeth, indicative of its lifestyle as a formidable apex predator. These blade-like teeth were used to prey upon marine animals, such as whales, dolphins, and likely other sharks.
Evidence of predatory behavior is well represented in the fossil record, with many examples of shark-bitten fossil bone (Figure 1). However, shark-bitten shark teeth are very rare. In a paper just published online in Acta Palaeontologica Polonica (DOI), paleontologists from the Calvert Marine Museum in Solomons, Maryland, USA and St. Mary’s College of Maryland describe four megalodon teeth that were bitten by other megalodon teeth. These bite marks are represented by shallow parallel lines marking the surface of the teeth caused by a forceful impact with the serrated cutting edge of another megalodon tooth (Figures 2 & 3).
Although the authors describe these very rare meg-bitten meg teeth, they do not know under what circumstances any of the megalodon teeth were bitten. One might imagine that the simplest way to account for megalodon-bitten megalodon teeth would be that two teeth in opposing jaws struck each other during occlusion, the serrated cutting edge of one marking the other. However, in lamniform sharks (the group of sharks to which megalodon belongs), the upper jaw protrudes beyond the lower jaw to such an extent that this would be unlikely. A tooth would have to have been contorted or at least partially out of place for the cutting edge to occlude with and mark an opposing tooth.
Another possibility is that a megalodon tooth was knocked loose for any number of reasons but remained in the originating jaw of the shark. This shed tooth (but still in the shark’s mouth) might then have been struck and marked by another occluding tooth.
A third possibility is that megalodon teeth became marked during a predatory or scavenging event. In this scenario, the tooth that would become marked became dislodged into the body of its prey (like a whale), when the prey was bitten. During a subsequent bite, one of its intact teeth would have serendipitously struck the shed tooth with sufficient force to mark it in the process. It has been calculated that the bite force of megalodon was more than 10 x greater than that of the modern great white shark Carcharodon carcharias. Consequently, there is no doubt that megalodon’s bite was powerful enough to produce these bite marks.
The authors of this study also envision the possibility of antagonistic encounters between megalodon, perhaps during territorial disputes, over mating rights, simple aggression, or during an act of cannibalism – either from active predation or scavenging, in which one individual forcefully bit the jaws of its rival (or the carcass of the conspecific being scavenged), marking the receiving tooth as part of that episode (Figure 4). As a potential modern analogue, living great white sharks (Carcharodon carcharias) occasionally engage in jaw-to-jaw aggression, possibly brought on during territorial and/or mating disputes, or simple naked aggression. Other sharks are known to also engage in acts of cannibalism, and intrauterine cannibalism is common among lamniform sharks. While we may never know exactly what events led to these megalodon-bitten megalodon teeth, we cannot help but appreciate the rarity of this preserving in the fossil record and the sense of curiosity sparked by these discoveries.
Figure 4. Here two megalodon aggressively attack each other, just one of the ways in which the fossilized teeth of megalodon might have become marked with serration marks from another tooth. Art by Clarence “Shoe” Schumaker, Courtesy of the Calvert Marine Museum.
Link to the paper: https://www.app.pan.pl/archive/published/app69/app011882024.pdf
Explore how the prehistoric past, natural environments, and maritime heritage come to life and tell a unique story of the Chesapeake Bay. The Calvert Marine Museum is open daily from 10 a.m. to 5 p.m. Admission is $11 for adults; $9 for seniors, military, and veterans with valid I.D, AAA and AARP members; $6 for children ages 5 – 12; children under 5 and museum members are admitted free. Proud participant in Museums for ALL. For more information about the museum, upcoming events, or membership, visit the website at www.calvertmarinemuseum.com or call 410-326-2042. Follow us on Facebook, Instagram, and X.