Time for another round of “What’s the Difference?” Maybe you’ve always wondered about something in the natural world, two things that seem to be so closely similar – why do they have different names?  Let’s investigate.

What’s the Difference between a TORTOISE and a TURTLE?
Actually, they are both turtles, the only shelled reptiles. Turtles have been around for about 18.5 million years. The seven basic kinds of turtles are mud and musk turtles, pond and marsh turtles, sea turtles (which can grow to 8 feet in length and weigh 1500 pounds), side-necked turtles that fold their necks along the side of their body instead of pulling it in, snapping turtles, soft-shelled turtles (some of whih can outrun a man!), and tortoises.

All tortoises live on land. All but one, the African pancake tortoise, have high, domed shells (the low-slung pancake tortoise protects itself by wedging its flexible shell into rock cracks). Tortoises can be as long as 4 feet and weight up to 600 pounds, with very stout legs to support their weight.

What’s the Difference between an ALLIGATOR nd a CROCODILE?
American alligators have relatively short, wide, rather blunt snouts. The big fourth tooth on each side fits into a pocket in the upper jaw out of sight when the mouth is closed. Fortunately for canoeists in Georgia’s Okefenokee swamp, alligators are less aggressive than crocodiles. Unprovoked attacs aren’t likely.

Crocodiles have longer, narrow snouts. They’re about one-third lighter than an alligator of the same length. The fourth tooth is left visible when the crocodile’s jaws are closed, giving the creature a sinister look. Crocodiles move more quickly than do alligators, are often aggressive, and must be considered very dangerous. It’s unlikely you’ll see one in the United States except at the tip of Florida, whereas alligators are found from North Carolina south around Florida, and west to the Rio Grande.

What’s the Difference between a DOLPHIN and a PORPOISE?
The names are often used interchangeably, as if the animals were the same. They’re not, though both are small whales. They are warm-blooded mammals, not fish. They breathe air, and must surface occasionally to blow out used air and suck in new. Every year, thousands drown after becoming entangled in fish nets.

Dolphins have pointed, beaklike snouts. The bottle-nosed dolphin is the one you see in shows. Those weigh 400 to 600 pounds, but larger ones may weigh tons. They have cone-shaped teeth and that familiar smirk. Dolphins travel in groups of as many as 1,000.

Porpoises are smaller: a big one might weight 220 pounds. They have flatter, sloped foreheads, spade-shaped teeth, and a round, blunt nose. No smile. They typically travel in groups of just two or four.

What’s the Difference between a MULE and a DONKEY?
Donkeys are domesticated wild asses. Originally from Africa, they’ve spread over the centuries to southern Asia and Europe. A small, surefooted variety called a burro is found in the Americas. Donkeys have been bred in a variety of sizes to suit a multiplicity of tasks. They’re renowned for sturdiness, unfussy diet, and stubbornness. Male asses are called jacks.

When a jack mates with a female horse (mare), the resulting animal is called a mule. If a female donkey (jenny) mates with a stallion, the progeny is called a hinney.

Donkeys bred for large size are called jackasses. Mated with big mares, they father mules as large as military horses, but much stronger and sturdier, and able to work harder and longer, particularly in hot climates. Both mules and hinny are sterile and cannot reproduce.

(The above information is from the Sierra Club, and their What’s The Difference Knowledge card deck. The deck is available through Pomegranate Communications, Inc. www.pomegranate.com )