CHICAGO May 8, 2013 - Lice make their home on the heads of approximately 12 million people in the U.S. every year. The thought of being host to these tiny insects with three pairs of legs creeps most of us out but at least lice do not spread diseases. They do however thrive by drinking our blood.
Contemplating lice makes you wonder if anything can be said about them except, “Ewww,” but a bit of investigation reveals that lice have a great deal to say about humans. Evolutionary biologists have been studying them to determine when humans began wearing clothes.
TIP: Although you may not feel it immediately, the most common head lice symptom is itching. People also complain of tickling sensations from the scurrying critters, red bumps on the head, neck, shoulder, or pubic area, problems sleeping, and sore spots from continuous scratching.
Although archeologists discovered sewing needles that are about 40,000 years old, they know that man left the warm climate of Africa long before that. To survive in colder environs we must have been clothed but before studying lice, no one knew exactly when humans first suited up.
The Story of Clothing As Told by Lice
Head lice have likely been with us from our beginning. They live only on the human scalp and cannot survive past a day without sipping our blood.
There is another type of lice called the pediculus humanus humanus, or clothing lice. It dwells only in clothing and bedding so must have evolved from head lice after mankind started wearing Stone Age duds. Unlike benign head lice, clothing lice can carry three diseases that are deadly to man, the most commonly known is typhus.
By studying DNA mutations, scientists determined when the genetic code for head lice took a fork in the genome road, creating the clothing lice population. It happened 170,000 years ago.
So, thanks to lice, we now know that our ancestors put us on the road to jeans and running shoes around 170,000 years before the birth of polyester. This is also when our predecessors began to journey north and out of Africa, carrying head and clothing lice with them.
TIP: To prevent the spread of pesky head parasites, advise your children to avoid head to head contact with other kids, and not to share personal items such as hair accessories, brushes, combs, hats, helmets, scarves, coats, towels, headphones, and earbuds.
The Plot Thickens
Just when you think lice have told us all they can about ourselves, scientists discover more. It seems these flightless critters that cannot jump reveal when man started losing body hair.
This story chapter is shared by pubic, or crab lice. The pubic lice variety did not evolve from head lice. Just to prove that life has a sense of humor, it turns out that our pubic parasites are genetically similar to gorilla lice. This makes it probable that we formerly ate gorillas or slept in their nests.
Scientists determined that head lice and pubic lice became separate human-loving species about 3 million years ago. It is believed this happened because man was losing his thick coat of torso hair, creating a distinct boundary between head and pubic lice zones.
TIP: An early louse preventive action is parting your child’s hair and looking for small, white nits, or lice eggs. Unlike dandruff flakes nits tend to stick to the scalp and hair. You can also check your kid’s clothing for lice or nits, especially hats, scarves, shirts, and coats.
How fascinating that missing pieces in the story of mankind were revealed by a reviled pest. It could be lice have even more juicy gossip to share. This does not make them less creepy-crawly, but it does emphasize that every living thing has an interesting tale to tell.
Evolution story source: Lice and Human Evolution
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