The snowy owl is among the largest owls in the world. (DIRK LAMMERS/AP)

Which of the following best describes owl pellets?

A. Owl vomit.

B. Owl poop.

C. Small pieces of chocolate shaped like owl eyes.

D. Fossilized owl bones.

The correct answer is A.

The most famous owl in the world is Hedwig, the snowy owl that Hagrid gave to Harry Potter. Although the owls in J.K. Rowling’s books are trusty companions, they are known for delivering mail, not owl pellets.

Owls, like hawks, falcons and eagles, are birds of prey. That means they feed on insects, fish, small mammals and even other birds.

Owls are known for having great eyesight and for being able to turn their heads much more than halfway around in search of prey. They can do that because they have 14 vertebrae (bones) in their necks instead of the seven that humans have, making them more flexible.

One of the differences between owls and other birds of prey is the way in which they eat and digest their food. Owls swallow their prey whole or in large pieces but do not produce enough stomach acid to digest bones, fur, feathers and scales. Because undigested body parts could injure the owl’s intestine, the animal needs another way to deal with that part of its diet. That’s where owl pellets come in.

An owl has two stomachs. The first one, called the glandular stomach, produces acids, chemicals and mucus that help separate the digestible and indigestible parts of its prey. The second stomach, called the gizzard, is very muscular and grinds up the meaty part of the meal.

Once the meat has been broken down, the digestible material moves into the owl’s intestine. The bones, fur, feathers and scales remain in the gizzard.

The owl’s gizzard continues to work, compressing the indigestible portion of the meal. After several hours, a gizzard-shaped owl pellet is produced.

Once formed, the pellet moves back into the owl’s glandular stomach. The pellet will remain there until the owl has finished absorbing all of the nutrients from its meal. That can take as long as 10 hours. At that point, the owl will regurgitate (vomit) the pellet and will be ready to eat again.

Some kids study owls in science class and get to dissect owl pellets. That is very cool, because they get to see the tiny bones and leftovers from an owl’s meal. If you aren’t going to do that in school, you can ask your parents to buy owl pellets over the Internet to dissect at home. It’s a good idea to have your mom or dad help with the process.

— Howard Bennett

Bennett, a Washington pediatrician, is the author of “Max Archer, Kid Detective.”