Head Lice, What Are They?

There are many different varieties of lice, living on many different types of animal's bodies. The head louse, as the name shows, lives in the human hair on the head and back of the neck.

You can get lice on other parts of the human body but these are a different type of lice. The head louse, Latin name (Pediculus humanus capitis) looks like a small ant when it is a fully grown adult, like an ant they have a head, thorax and abdomen with six legs, although the louse has extra long front legs to help grip onto the hair.

The Life Cycle Of A Head Louse

A head louse starts of life in an egg that the female louse has laid a centimeter or so away from the scalp; these are "glued on" by the female so they do not fall away from the scalp.

The eggs are anything from white to brown in color and are the size of a grain of sand, which is tiny. The incubation period is between seven and nine days, once hatched the baby louse is called a nymph.

You may hear people refer to the term "nit" when talking about head lice, this term refers to the empty egg the nymph left behind or a dead egg that did not finish its incubation cycle. A nit is normally found further away from the scalp than an egg in the incubation stage; a nit is usually around two and a half centimeters from the scalp.

A head louse nymph goes through three stages before becoming an adult head louse. As the nymph nears the end of each stage it sheds it exoskeleton so it can carry on growing. The total length of time to complete all three stages as a nymph before maturing to an adult is ten to twelve days.

The sex of a head louse is not apparent until it matures from the nymph stage into an adult. The lifespan of an adult head louse is about thirty days, a female louse cannot start laying eggs until it has become an adult, and from this period it can lay between three and seven eggs per day for its entire lifespan.

Recap

-- Head lice are only found in the hair of the human head and neck

-- The adult head louse looks like a tiny ant with extra long front legs for grip

-- A louse starts life as an egg glued to human hair about one centimeter from the scalp

-- A head louse egg is about the size of a sand grain

-- A nit is the empty or dead egg of a head louse

-- It takes 7 to 9 days for a louse egg to hatch

-- The baby louse (nymph) goes through three stages before adulthood, shedding its exoskeleton at each stage

-- A louse does not have a sex until it matures into an adult

-- The lifespan of an adult head louse is about thirty days

-- An adult female can lay between 3 and 7 eggs a day