Male black widow spiders are quite a bit smaller than females, usually about half their size, but they have longer legs. The male measures approximately ¼” in body length. The male's abdomen is more elongated and is not large and rounded like the female's.
The females are well known because of their black color and unique hourglass marking. The males are sometimes lighter in color, but exhibit more colorful patterns than the female. They have streaks on their abdomens and patterns on their backs, usually spots and lines that branch out to the sides.
A male black widow will recognize a female by the pheromones in her web. He will use a vibration technique to put her in somewhat of a trance and attempt to mate. Contrary to popular belief, females rarely eat males after mating.
The bite of the male black widow is not harmful to people, unlike the bite of the female. Once a male reaches maturity, his venom sac is not functional. The juveniles are also harmless and, whether male or female, resemble an adult male in appearance. They are light yellow or whitish in color when they first hatch. As they get older, they become darker in color.