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
(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.
Further Reading:
Ant
behavior by Alex Wild, Myrmecos.net, http://www.myrmecos.net/antbehavior.html
Ants of South East Asia, www.antbase.net
Trap-jaw mechanism by Wulfila Gronenberg, The Journal of Experimental
Biology 199, 2021–2033 (1996)
Morphological and Functional Diversity of Ant Mandibles by Chris A. Schmidt,
Tree of Life Web Project
The number of ants in the world, The Physics Fact Book
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
Further Reading:
Snoring: analysis, measurement, clinical implications and applications by F.
Dalmasso, R Prota, European Respiratory Journal, 1996, 9, 146-159.
http://www.erj.ersjournals.com/cgi/reprint/9/1/146.pdf
Snoring, bupa.com
The effects of
snoring, The Franklin Institute
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)
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