How to Identify Northern U.S. Spiders

Examine the spider for distinct coloring. If the spider is black with a red hourglass on the abdomen, it can be a female black widow who has a venomous bite. This northern American spider can be very aggressive. Northern spiders that are black with striking yellow markings are black and yellow gardens spiders. They are orb weavers that can be found in fields, high grasses, outhouses, and eaves of homes. They are harmless to humans. Spiny micrathena are black spiders with a white spiny abdomen with black markings.

Study the size of spiders. Most spiders in northern United States like the spiny micrathena and jumping spiders are about a half inch long. Exceptions are the longjawed spider with its long narrow body reaching one inch long. Another exception is the cobweb spider that is commonly found in homes reaching no larger than a quarter inch in length.

Observe the behavior of northern United States spiders. Jumping spiders hunt for prey on the ground, typically in the evenings. Jumping spiders have excellent eyesight with two small and two large eyes. They hide when they see prey and jump onto it when it passes by. Crab spiders camouflage themselves on flowers of similar colors such as yellow and orange while they wait for prey. Their bodies are flat and angular and they walk sideways, like crabs.

Examine the spiders web. Northern United States spiders have various kinds of webs. For example, the starbellied orb weavers makes large zig-zag designs in their webs. The yellow and black garden spider has small zig-zags in their webs and jumping spiders create small webs that are used to hold their eggs and not for capturing prey. Spiny micrathena spiders spin their webs tightly coiled and perfectly round.