There are several types of centipedes in the United States. Some of them invade homes occasionally. The centipede that probably frightens the most people is the Giant Desert Centipede. It is also called the Giant Red-headed Centipede and the Poisonous Black Centipede. This creature's scientific name is Scolopendra heros.
There are other Scolopendra centipedes around the United States and people often confuse them. Scolopendra polymorpha, the Sonoran Desert centipede lives in the southwestern states. Its territory overlaps with the S. heros. The Scolopendra alternans is a member of this group that is found in Florida.
These giant centipedes often grow longer than 7″. They are active at night. In poor light, their dark brown bodies may look black. It is possible that this is the reason some people call them the poisonous black centipede.
Centipedes have specialized claws near their heads. These claws are connected to venom glands. The centipedes eat insects and spiders. They normally use their venom to paralyze their prey. If they are threatened, they will readily bite a person. They probably perceive a human hand reaching to pick them up as a threat.
The danger from these centipedes actually seems to depend on the person who is bitten. Most people feel a sharp pain when a centipede bites them. The bite site often swells and turns red. Many times the area itches. For most bite victims, these symptoms begin to disappear in a few hours.
For some people, the symptoms last longer. These people may feel tenderness around the bite site for several weeks. The swelling may last and sometimes they get a sore where they were bitten.
A few people are very allergic to centipede venom. These people may get headaches and nausea. They may feel dizzy and they may have changes in their blood pressure. Sometimes these symptoms do not appear for an hour or more after the bite happens.
It is common for elderly people, children, and people who have been ill to have severe symptoms if they receive a bite from a centipede. Bite victims should be observed closely. If they show signs of a reaction, seek medical attention.