Dinosaur unearthed in Fort McMurray oilsands was carried to watery grave by 'bloat and float'
'As a big-gutted ankylosaur, you have lots of big digestive chambers that fill up with the rotting gasses'
A dinosaur famously unearthed from a Fort McMurray oilsands mine was likely the victim of "bloat and float," says Edmonton paleontologist Scott Persons.
"It had sunk to the bottom and settled down into the very fine silty sediment of the sea floor, before scavengers could disturb it and before the skeleton fell apart," Persons said during his dinosaur series with CBC Edmonton's Radio Active.
"Bad stuff usually happened to their bodies. They got torn apart by scavengers, or their carcasses rotted and their skeletons fell apart into a big jumble.
"But not the Borealopelta specimen."
Much like the opening scene of a murder mystery: a few hard-working labourers were going routinely about their jobs at the remote mine, when they stumbled across the specimen.
A team of expert detectives is called in to investigate, and a slew of mysterious circumstances surface.
The fossil, which is now the centrepiece of a recently opened exhibit at the Royal Tyrrell Museum near Drumheller, is part of a larger paleontological mystery, said Persons, a PhD student at the University of Alberta.
The armoured herbivores, not much larger than the modern hippo, were land animals but their fossils are most often found in areas that were once submerged in prehistoric ocean.
How did the "Suncor Ankylosaur" reach its watery grave? Paleontologists believe they have cracked the case.
The dinosaur likely died in an inland marsh, and as it began to rot, its distended body was carried out to sea, Persons said.
"Bloat and float, that's something not uncommonly observed today, when the carcasses of cattle can be found bobbing up and down in the ocean," said Persons.
"Or when the corpse of an Indian elephant is seen floating down even a shallow portion of the Ganges River."
Persons hypothesizes that the dinosaur was living in the wetlands of prehistoric Alberta, it died of natural causes.
'Like really gross balloons'
"Imagine this, you are an elder Borealopelta living it up in the wetlands of prehistoric Alberta, but the time has come to shuffle off your mortal coil."
It died, but not in a violent way, said Persons.
"You aren't torn apart limb from limb by a hungry tyrannosaur or pack of raptors. You're done in by a disease, or a heart attack, or maybe you drank some bad swamp water," Persons said.
"As your body sits in the subtropical sun, you start to rot. Bacteria feeding on your soft insides produce gas as a byproduct."
You're done in by a disease, or a heart attack, or maybe you drank some bad swamp water.- Scott Persons, paleontologist
The ankylosaur, one of the best-preserved specimens of its kind, is the perfect example of this puzzling phenomenon, said Persons.
The combination of having extra big guts and heavy armour, which would bring the carcass quickly to the bottom of the briny deep, made ankylosaurs particularly prone to bloat and float.
From fossil records, paleontologists can tell that these armoured animals had great barrel-shaped bodies designed to house lots of digestive vats and looping intestines.
"As a big-gutted ankylosaur, you have lots of big digestive chambers that fill up with the rotting gasses quickly and swell, like really gross balloons.
"That's the bloat."