“The preservation of dinosaur feces is pretty rare,” said Donald Henderson, curator of dinosaurs at the Royal Tyrrell Museum in Drumheller, Alta.
Feces stand a good chance of being destroyed by rain, washed away or eaten by other animals unless they are rapidly buried.
“A skeleton can be broken up and swept downriver and we can still find the bones,” he said.
“But once feces get disturbed, it’s gone.”
However, samples have been found despite the difficulties.
Henderson said it is almost impossible to tell the exact kind of dinosaur that made the fossilized feces, which is known as coprolite.
“The best we can say most times is if it is a plant eater or meat eater,” he said.
Henderson said Tyrannosaurs rex coprolite found in Saskatchewan is kept at the T.rex Discovery Centre in Eastend, Sask.
Researchers know it was this particular dinosaur because bone fragments were found inside the loaf-sized coprolite. The T.rex was the only carnivore in the area 65 million years ago.
“It’s thought that the bone mineral actually helped encourage fossilization of the material,” said Henderson.
Tim Tokaryk, curator of vertebrate paleontology at the centre, said the coprolite was discovered a year after the skeleton of Scotty, the T.rex at the centre, was unearthed.
“We were able to determine the bones contained in this coprolite were from a juvenile dinosaur, possibly a triceratops or duck-billed dinosaur,” said Tokaryk.
Karen Chin, curator of paleontology at the University of Colorado, said she worked on a project at the Tyrrell Museum that involved carnivore coprolite with fossilized muscle tissue inside.
“When the dinosaur ate some of its prey, the pieces of meat that it ate were not fully digested,” she said.
The coprolite would have had to be rapidly buried and mineralized, she added. Otherwise, the muscle tissue would have easily decomposed.
Carnivores leave behind interesting remains, but Henderson said he has come across herbivore coprolites that contained twigs, small wood fragments and plant needles.
“They don’t grind their food up the way we do. At best, they chop it up into smaller pieces, then swallow that,” he said.
Pieces of wood were found in a duck billed dinosaur’s feces that contained insects.
“The thinking is, what if the animal was eating the wood to get the bugs and protein?” Henderson said.
Chin said researchers have found evidence of dung beetle burrows in some coprolite samples, which she said dated dung beetle activity to as far back as at least 75 million years ago.
“That’s why coprolites, for me, are really interesting,” she said.
“Because they can provide evidence for links between these different animals.”
Examples of coprolites have been found across Saskatchewan. Tokaryk said the centre in Eastend has some from the Assiniboia area and near Rouleau, Sask., but researchers aren’t sure which dinosaur made them.
Henderson said coprolites have also been found in the Dinosaur Provincial Park near Brooks, Alta.
He said the climate in Saskatchewan during the dinosaur era was wetter than other places, which made it difficult for coprolites to be preserved.
However, marine dinosaur coprolites have been found from when Saskatchewan was covered by water 100 to 67 million years ago.
“In order to preserve dinosaur feces, they had to fortuitously defecate in a place where the feces would be buried rather quickly, usually in river environments,” Chin said.
“In one case, we even found one in a tidal flat.”