What is a coprolite?

Fossil collector Mary Anning lived in Lyme Regis, Dorset, in the early 1800s. She’s remembered for making a number of important fossil discoveries of extinct animals, including ichthyosaurs and plesiosaurs – large reptiles that lived in the sea.

But these creatures weren’t all she found on her collecting trips along the Jurassic Coast near Lyme Regis.

In the video above, local fossil hunter Heather Middleton explores the less glamorous side of the legendary collector’s career: fossilised poo.

What can we learn from coprolites?

Coprolites are the fossilised faeces of animals that lived millions of years ago. They’re trace fossils, meaning not of the animal’s actual body.

By looking at the shape and size of coprolites, as well as where they were found, scientists can work out what kind of animal the droppings might have come from. Coprolites can also contain clues about an animal’s diet.

For example, a spiral-shaped coprolite may have been left by an ancient shark or another kind of fish. This is based on the knowledge that some modern fishes such as coelacanths and sharks have spiral-shaped intestines.

It’s difficult to find out exactly what animal produced a prehistoric poo, however, as fossils of the animal’s body are not usually found in the same places as the fossil faeces.

It’s easier to tell whether the animal was an ancient meat-eater or a vegetarian.

Dinner clues

Scientists can look inside coprolites to see what they contain. If there are bone fragments, the animal was a carnivore. Tooth marks on the fragments, if present, can reveal how the animal ate its prey.

“Mary was really the first person who looked inside these fossils and saw the remains of fish, with scales and bone,” says Heather. “This prompted William Buckland, who was a well-known geologist, to confirm that they were coprolites, which are fossilised faeces.”

Seeds, leaf remains, pollen or bark found in a coprolite suggest that the animal it came from ate plants.

Experts can use powerful microscopes to look at what’s normally invisible to the naked eye.

When magnified, plants often have distinctive shapes and patterns, making it possible for scientists to work out what type of plant they are looking at – even when it’s partly digested and inside a coprolite. So scientists can learn about both a prehistoric animal's diet and which plants were growing in its habitat at the time.

Go on a fossil hunting adventure

What fossils could you unearth near you and what might they tell you about prehistoric animals and their habitat? Discover how to go on your own fossil hunting expedition on your next trip to the beach.

Help to identify your fossil finds is available from our Identification and Advisory Service.