Known scientifically as Latrodectus hasselti, the redback spider is from the widow family and is most often found in Australia. It is a deep brown or black with a bright red marking on its back. Unlike some other spiders, the redback spider builds a very tangled web with no discernible pattern. Male widow spiders usually are eaten during the mating process or — if they survive — die soon afterward. People who have been bitten by redback spiders rarely show symptoms, and the spiders are not naturally aggressive toward humans, so the number of recorded deaths are few.
Young female redback spiders are a deep brown color rather than black. They also have white spots in addition to a red stripe. When they grow older, their color deepens, and the spots disappear. Males resemble juvenile female spiders, and they always stay small.
A redback spider web is not an intricate display like some other webs. In fact, these spider webs resemble fake webbing that can be bought in costume stores. On the other hand, the webs usually are quite strong. They typically are located near the ground and can be found in many places that are dry. The actual spider usually can be found hiding in a corner of the web with her eggs.
Like other spiders from the widow family, female redback spiders kill their mates by eating them. They usually begin eating the smaller male spiders during the process of mating. Sometimes the mating continues even after the male redback spider has been mostly eaten. After a successful mating, the female spider can make eggs for as long as two years, enclosed in about four sacs. It takes about two weeks for the baby spiders to hatch, then they travel to a new location when the wind picks up and blows them away.
Redback spiders are not considered to be aggressive, but they can bite if threatened. Most cases of redback spider bites occur when a person accidentally disturbs a web. Spiders can be protective over their webs, especially when guarding egg sacs. This kind of spider is mostly dangerous to children, elderly people and people who are ill. Only a few dozen fatalities are known to have occurred because of redback spider bites.
Although they are potentially dangerous, redback spiders are of little threat to the vast majority of humans. Still, some caution should be exercised when one is outdoors in Australia. Attempting to kill the spiders with chemicals usually is pointless. Some of the spiders die, but they are quickly replaced by more. In addition, the chemicals kill redback spiders' natural predators, which results in even more redback spiders.