Answers to your questions about chelonians

• What is the difference between a turtle and a tortoise?

• What do you call a group of turtles?

• Do turtles have teeth?

• How big is the largest desert tortoise?

• What is the largest species of tortoise/turtle?

• Can turtles breathe through their butts?

What is the difference between a turtle and a tortoise?

In common usage in the United States, the word turtle is an inclusive word that refers to all species of water turtle, sea turtle, box turtle, terrapin and tortoise. The word tortoise refers to a particular type of turtle that is well adapted to life on land.

Scientists group all turtles together in the "order" known as TESTUDINES. This order includes about a dozen living "families" of turtle. Tortoises are a specialized clade or subgroup of the order TESTUDINES that are known as the Testudinidae.

According to Dr. Kristin Berry, the following distinction is made between the terms "turtle" and "tortoise" in the US:

"A tortoise is a land dwelling turtle with high domed shell and columnar, elephant-shaped hind legs. Tortoises go to water only to drink or bathe. In contrast, the word turtle is used for other turtles: pond turtles, river turtles, box turtles, musk turtles, sea turtles, etc.

So, tortoises form a subgroup that can be distinguished from other groups of turtle, but they are "turtles" nonetheless.

Michael J. Connor

What do you call a group of turtles?

Although people who keep pet turtles tend to use the collective term "herd" to refer to a group of turtles, the classic collective term is a "bale of turtles."

Michael J. Connor

Do turtles have teeth?

While some prehistoric turtles had them, no modern turtles possess real teeth. Instead, all of the turtles alive today have very sharp beaks which they use to bite with. Hatchlings emerge from their eggs using what is commonly known as the egg-tooth or caruncle. This is located at the front of the upper jaw and typically it disappears a few months after the turtle hatches. It is a modified scale and not a real tooth.

Michael J. Connor

How big is the largest desert tortoise?

The largest recorded desert tortoise is "Maximus," a captive tortoise measuring 15 inches in carapace length and weighing 23 pounds (St. Amant, 1976). Maximus had been a pet for many years and was turned into the California Department of Fish and Game office in Long Beach in the 1970's.

Maximus, the largest known desert tortoise at 23 pounds (10.4 kilograms) and 15 inches (38 centimeters) carapace length. Photograph by J. A. St. Amant