WonderQuest with April Holladay, Article printer-friendly version

An ant's many teeth; Sound asleep snoring

Q: How many teeth do ants have? Hatheem, Colombo, Sri Lanka

A formica ant suspends a drop of aphid honeydew between her mandibles as she drinks it. Photo courtesy of Alex Wild, copyright, used with permission.

A Formica ant suspends a drop of aphid honeydew between her mandibles (which bristle with 7 or more teeth), as she drinks it. Photo courtesy of Alex Wild, copyright, used with permission.

A: How many teeth an ant has depends on which of the 12,000 ant species we're talking about. The creatures roam planet-wide, except for Antarctica and a few oceanic islands.

Early ants had only two teeth, but most modern ants have more — although some are "nearly toothless," emails entomologist Alex Wild of the University of Arizona.

In fact, although totally lacking teeth is a relatively rare condition, many ants do nearly lack teeth. Larger workers of "nearly toothless" species may have slight hints of teeth but smaller workers have none.

Most ants, though, have teeth. Larger ant species typically have more teeth than smaller ones, and the number varies from about two to at least eighteen teeth per mandible.

The teeth are made of the same tough stuff as an ant's exoskeleton. They look like, and are, extensions of the mandibles.

Some ants have many, sharp teeth to penetrate and hold a soft-bodied, squirmy insect long enough to sting it. But such teeth break when the mandibles snap together on a tough foe like a termite soldier. Ants after hard-bodied prey have blunt teeth, and crush the insect with a blow like a sprung trap from their quick-closing jaws.

Mandibles of some ants can slam shut in 0.3 ms, a thousand times faster than an eye blink, says neurobiologist Wulfila Gronenberg of the University of Arizona.

Few ants can exert enough jaw pressure to penetrate human skin. The painful 'bite' we feel is actually a venomous sting. An African driver ant, however, can bite with her sharp teeth hard enough to hurt a person badly. In fact, these fierce insects can swarm over a large mammal, and literally slice it to death. "The soldiers of the Neotropical leafcutter ants can also easily break the skin with their bites," says Wild.

Q: Why do people only snore when they are asleep? You breathe all the time, but it's noisier when you are fast asleep. Why? Hank, Boise, Idaho, USA

A man breathing in air (shown as a blue line) through his mouth. Drawing courtesy of Gray's Anatomy of the Human Body.

A: We almost cannot snore while we're awake, because we cannot relax critical muscles enough to snore. For normal adults, that extreme decrease in muscle activity only happens in the deeper stages of sleep. When awake, muscles keep even the most constricted part of the passage open enough, for air to quietly scoot down.

Airways are narrowest around the roof of our mouths (the soft palate), the back of our tongue and along the air passage at the back of the mouth (the oropharynx). See figure.

From time to time, about 45% of us snore. Then, as we sink into deeper sleep and our bodies relax totally, the passageways partly close and we snore. Inhaling, we not only suck in air but also tend to suck the soft parts of the passageway together and restrict the airway. The muscles surrounding these soft areas (the soft palate, the back tongue and the oropharynx) tighten to prevent airway collapse, but can't contract enough to keep the passage wide open and air flowing freely. Restricted airflow vibrates sagging soft tissues. Fluttering tissues produce a snore, somewhat like a bagpipe's vibrating reed drones its tune.

About 25% of us snore habitually. But there is one sure cure for snoring — eliminate gravity's effects. "Free falling in orbit, we do not snore, as there is no gravity to pull on the soft tissues," emails pulmonary physiologist Kim Prisk professor at the University of California at San Diego.

My wife says I make a noise like a stranded whale. — Rex Hunt

Readers' answers to question of the month:

People snore when sleeping, because the muscles in your tongue, throat and mouth relax, causing throat tissues to sag. As you breathe, these sagging tissues narrow your airway, and vibrate or flutter, causing the sound of snoring. The narrower the airway, the greater the sound of snoring.

Neelie, Sutton-in-ashfield, England

When people sleep, their muscles relax, including those at the back of the throat. This relaxing causes the soft tissue at the back of the throat to vibrate when they breathe. We call it snoring.

Mary Lou, North Bay, Ontario, Canada

It is the only way to annoy others, while you sleep. While awake, you can annoy others in a wide variety of behaviors.

Kenneth, Centennial, Colorado, USA

Next month's question:

Swans. Photo courtesy of Wikipedia.

Recently we were sitting outside and heard a bizarre noise coming from something flying over our heads. We realized it was a couple of swans. Now we are trying to figure out what the noise was. Some of us suggested it was a sort of singing or signaling, others that it was their wings making the noise. Can you help us out? We have a dinner at stake!! Mimi, Copenhagen, Denmark

I'll publish the best answers, and you get credit. Click here: Answer-the-question
to give me your answer.

(Answered June 2, 2007)