Details of ancient shark attack preserved in fossil whale bone

Nov 10, 2011
Whale bone fossil showing three tooth marks from a shark. The marks on the rib indicate the whale was once severely bitten by a strong-jawed animal. Judging by the 6 centimeter (2.4 inch) spacing between tooth marks, scientists believe the attacker was a mega toothed shark Carcharocles megalodon, or perhaps another species of large shark which was alive at that time. The whale appears to have been an ancestor of a great blue or humpback. Credit: Photo by Stephen Godfrey

A fragment of whale rib found in a North Carolina strip mine is offering scientists a rare glimpse at the interactions between prehistoric sharks and whales some 3- to 4-million years ago during the Pliocene.

Three on the rib indicate the whale was once severely bitten by a strong-jawed animal. Judging by the 6 centimeter spacing between tooth marks, scientists believe the attacker was a mega toothed shark Carcharocles megalodon, or perhaps another species of large shark which was alive at that time. The whale appears to have been an ancestor of a great blue or humpback.

"One certainly doesn't expect to find evidence of animal behavior preserved in the , but this shows just that, a failed predation," explains Stephen Godfrey, at the Calvert Marine Museum in Solomons, Md. and a Smithsonian research collaborator, who discovered the fossil. "The shark may have gone away with a mouthful, but it didn't kill the whale"

Scientists know the whale survived because "most of the fossil fragment is covered with a type of bone known as woven bone, which forms rapidly in response to localized infection," explains Don Ortner, an anthropologist at the Smithsonian's and authority on the effect of disorders on skeletal tissue. "Biomechanically woven bone is not very strong. The body eventually remodels it into compact bone, but it takes time." CT scans reveal evidence of inflammation in the bone marrow consistent with infection.

This illustration shows one plausible way, and the most likely, in which the three calluses preserved on the whale rib came about: a bite from one of the large Pliocene sharks with which these huge baleen whales had to contend. Credit: Illustration by Timothy Scheirer © CMM

The presence of the woven bone indicates the healing was incomplete and the whale died, the scientists estimate, between two and 6 weeks after the attack. The whale's death may have been unrelated to its infection and injury, Ortner says. "We don't know why it died."

Based on the curvature of the shark's jaw, as indicated by the arc of the impressions of its teeth, the scientists believe the shark was relatively small, between 4- and 8 meters long.

In the realm of paleontology, "only a handful of fossils show these kinds of interactions," Godfrey explains. "There are lots of bite marks on fossils showing where the animal died and its carcass was scavenged. This fossil is one of a very few examples that shows a trauma clearly attributed to another animal, yet also shows the victim survived the event."

Explore further: Micro-scale technique helps preserve rock art legacy 

More information: "Bone Reactions on a Pliocene Cetacean Rib Indicate Short-Term Survival of Predation Event" was published in the International Journal of Osteoarchaeology.

Related Stories

Bone-eating 'zombie' worms can no longer hide

Oct 31, 2011

Bone-eating 'zombie' worms may be good at keeping out of sight, living off dead whales in the darkness of the sea floor, but scientists have found out how to detect them, even if there’s no trace of their ...

Second ancient whale found in Italy

Apr 02, 2007

The skeleton of a 33-foot-long prehistoric whale has been discovered in what was once an ancient seabed in Italy's Tuscany region.

Oily whale bones puzzle solved

Aug 31, 2010

The puzzle of why some oily whale bones make great habitats for weird and wonderful deep sea creatures has been solved by Natural History Museum scientists this month.

Recommended for you

Archaeologists, tribe clash over Native remains

17 hours ago

Archaeologists and Native Americans are clashing over Indian remains and artifacts that were excavated during a construction project in the San Francisco Bay Area, but then reburied at an undisclosed location.

User comments : 0

More news stories

Male-biased tweeting

Today women take an active part in public life. Without a doubt, they also converse with other women. In fact, they even talk to each other about other things besides men. As banal as it sounds, this is far ...

Not just the poor live hand-to-mouth

When the economy hits the skids, government stimulus checks to the poor sometimes follow. Stimulus programs—such as those in 2001, 2008 and 2009—are designed to boost the economy quickly by getting cash ...

Archaeologists, tribe clash over Native remains

Archaeologists and Native Americans are clashing over Indian remains and artifacts that were excavated during a construction project in the San Francisco Bay Area, but then reburied at an undisclosed location.

Phase transiting to a new quantum universe

(Phys.org) —Recent insight and discovery of a new class of quantum transition opens the way for a whole new subfield of materials physics and quantum technologies.

Imaging turns a corner

(Phys.org) —Scientists have developed a new microscope which enables a dramatically improved view of biological cells.