Lice are considered to be one of the oldest parasites in existence. Lice refer to three different types of human parasites. The parasites include head lice, body lice, and crab lice. All three forms of lice have been present since ancient times.
The most ancient specimens of nits (lice eggs) are 10,000 years old and were first found in Brazil.
A louse was discovered attached to hair that was dated to 10,000 years ago. This discovery was proof that head lice had affected humans for 10,000 years or longer. This is also evidence that nits can attach to human hair for a very long time.
Female head lice glue their nits to individual strands of hair. The nits are fixed to the hair by a glue-like substance. Nits are oval-shaped and very small. They can be difficult to see.
The glue-like substance hardens and is extremely resistant to chemical and biological breakdown which could explain why the 10,000-year-old nit found in Brazil was still attached to the hair. While the nit is no longer alive, the glue is so hardy that it stayed attached to the human hair.
Even after the nits have hatched and the nymph emerges from the shell, the empty eggshell remains glued to the hair.
Scientists have also used the lice glue to study the DNA of humans that were infected by lice. The lice glue is reported to help trap and preserve anything it encases including human DNA.
The study of ancient lice and nits has provided scientists with information about the evolutionary and natural history of both lice and humans.