An archaeologist shows one of around 700 coprolites that were discovered in caves in Oregon. Some of the fossils were estimated to be 14,300 years old. (Jeff Barnard/Associated Press)

Let’s start out with a little quiz.

Which of the following best describes a coprolite?

A. a stalactite that’s composed mostly of copper

B. an energy drink

C. a rechargeable battery

Two specimens of coprolite, or fossilized dinosaur dung, are shown. (Associated Press)

D. fossilized dung

Wrong answers

If you’ve ever visited Luray Caverns in Virginia, you have had the pleasure of seeing stalactites firsthand. These geologic wonders, which are thousands of years old, are made from mineral deposits (mostly calcium carbonate) that remain after water drips from the ceilings in limestone caves.

Energy drinks are advertised a lot on TV. The active ingredient in these products is caffeine, which is the chemical in coffee and tea that helps adults stay alert. Doctors never want kids drinking this stuff. You should have all the energy you need by eating a healthful diet, exercising and getting enough sleep at night.

Batteries are one of the coolest inventions of all time. They work by converting chemical energy into electrical energy. Batteries usually are made from heavy metals such as copper, zinc and lithium. One of the weirdest batteries ever invented used urine (pee) as its energy source.

Correct answer

A coprolite is fossilized dung (or poop). Although coprolites can come from the feces of any animal, the most famous ones were produced millions of years ago by dinosaurs. The largest coprolite ever found was 17 inches long and almost seven inches wide. Because it contained a lot of bones, paleontologists think it came from a large carnivore, such as a Tyrannosaurus rex.

Here are some other fascinating facts about coprolites.

●When an animal or plant dies, it is usually decomposed by bacteria and fungi that live in the soil. Like animals, poop can become fossilized if it gets buried in sediment (sand, mud, ash) that protects the organic material from being broken down.

●Because feces decay rapidly, coprolites are very rare.

●Although sauropods (long-necked, plant-eating dinosaurs) produced up to a ton of poop every day, carnivore dung was more likely to become fossilized because it contained calcium-rich bones and teeth that decomposed more slowly than plant matter.

●Coprolites tell scientists a lot about what an animal ate and how it lived.

●Coprolites are referred to as “trace fossils” because they reveal information about animal behavior. Skeletons are referred to as “body fossils” because they reveal information about animal structure.

●Some herbivores do not have teeth that can shred the plant matter they eat. To solve this problem, they swallow stones that remain in their stomach and tumble around to help them grind up what they eat. According to the book “Dino Poop,” coprolites have been found inside dinosaur skeletons. That implies that some dinosaurs mistook coprolites for stones and unknowingly swallowed fossilized poop to help digest their dinner!

Bennett is a Washington pediatrician. You can read more fun (and gross) stuff he has written at