Most northern black widows offer a distinct appearance. They are jet black and glossy in appearance with an hourglass-shaped marking on their abdomen. The hourglass shape is usually bright red, and the bottom half of the northern widow's hourglass marking is rounded. Most of these spiders also feature a small row of dots and white stripes down the sides of their abdomen. The average female northern widow spider body size is around 0.5 inches; average leg span is between 1.5 and 2.0 inches. The average male northern widow spider is much smaller than the average female, they will only grow to around 1/3 the size of a female.
Not all widow spider bites are potentially lethal. Only female northern widow spiders are considered dangerous, their bite can be deadly. Male northern widow spiders pose no threat to humans, their bite is harmless. The most likely time to encounter this typically non-aggressive spider is at night, as they are nocturnal. These spiders typically bite only as a defensive measure when they feel threatened or get attacked. The northern widow spider is very protective of its web and will aggressively defend it, if egg sacs are present.
The average spider spins a relatively flat web. Northern widow spiders spin webs that do not resemble the web of a typical spider. A northern widow spider's web more closely resembles a cobweb. Webs from this type of spider can be found throughout Minnesota under logs, rocks, in crevices, cracks -- and basically anywhere that is sheltered from the weather. People may find northern black widow webs in sheds, barns, garages and under lawn furniture.
Northern widow spider bites can be fatal if enough venom is injected. Venom from a northern widow spider can weaken the brain and nerves, leading to body aches, nausea or impaired breathing. Very young and very old people are more likely than young adults and middle-aged people to die from a northern widow spider bite. Anyone that has been bitten by a northern widow spider should seek medical attention immediately.