Prehistoric puke reveals hunting (and hurling) habits of ancient ocean predators

As It Happens6:13Prehistoric puke reveals hunting (and hurling) habits of ancient ocean predators

What is 66-million-year-old vomit like? A lot more pleasant than the fresh stuff, says paleontologist Jesper Milan.

"It doesn't smell anymore," he told told As It Happens host Nil Kӧksal. "It doesn't look disgusting at all."

That's good news for the patrons of Denmark's East Zealand Museum, where Milan is a curator, and where the preserved puke of a prehistoric ocean predator will soon be displayed.

Discovered by a private fossil hunter on a historic coastal cliff in Denmark, Milan says it offers a rare glimpse into the hunting habits of sea creatures in the Cretaceous period.

'Oh, this could be vomit'

When Milan first laid eyes on the fossil, which is about 3.5 centimetres in diameter, he says it didn't look like much at all. 

But as museum staff dusted it off and cleaned it up, they revealed the skeletal remains of two crinoids — small, tentacled marine invertebrates, better known as sea lilies — coiled together in a pellet.

"That's when we started to think … oh, this could be vomit," Milan said.

That's great news to a paleontologist, because vomit offers clues about ancient ecosystems — namely who was eating what and when. 

But it's also hard to come by. 

"Normally, vomit is mostly soft things that don't get fossilized," Milan said. "It must have got buried in the seafloor quite fast."

The scientific name for fossilized vomit is regurgitalite.

"They're really rare, and they're really important," Russell Bicknell, a paleobiologist at the American Museum of Natural History who was not involved in the Danish discovery, told CBC.

Regurgitalites, Bicknell says, are a sub-category of bromalites, which are fossilized digestive materials.

There are also colonites, food preserved in intestines, and perhaps the most popular of them all, coprolites, a.k.a. fossilized feces.

Bicknell also studies ancient ocean predators, but with a focus on the Cambrian period, between 538 and 485 million years ago, which had excellent geological conditions for fossil preservation. 

For the Cretaceous period, he says, bromalites are more rare. And this one dates to a period just before the mass extinction event that killed off the dinosaurs. 

"It's from the period just before the meteorite hit the Earth," he said. "That's really exciting."

What did the puking?

So far, scientists don't know what actually did the puking. It may have been a fish, or a marine reptile, gobbling up sea lillies along the bottom of the ocean. 

Sea lilies, which predate dinosaurs and still live on the ocean's floors today, have skeletons are made of mineral calcite, which explains why they were so well-preserved in the regurgitalite.

Their skeletons consist of hundreds of individual plates of different shapes and sizes, which could explain why they didn't go down very well. 

"There's not many animals that like to eat things that are particularly spiky or shelly," Bicknell said. "Either this particular animal really enjoyed this kind of food, which is interesting, or maybe there was kind of a limitation on what could have been eaten at the time in that environment, so it was kind of limited to the more, you know, crunchier."

Milan has some theories. 

"You have a few possibilities, but my main suspect is one of the small bottom dwelling-sharks that are still alive today," he said. 

"Bullhead sharks, or the Port Jackson Shark, they feed on the sea starfish and sea urchins and mussels and crayfish and a lot of things with hard shells. And you find the fossilized teeth from that kind of shark in the same deposit as as the vomit."

Whatever barfed out the sea lilies, Milan says he's grateful for the international attention they're receiving, and for Peter Bennicke, the 79-year-old fossil hunter who found the prehistoric puke.

He says roughly two thirds of fossils on the record in his country come from amateur fossil hunters, and he encourages them to keep doing what they're doing. 

"They are doing a great job in Denmark," he said.