Imagine, if you will, a pair of pigeons on a rooftop.

They see you walk by on the street below. One of the pigeons exclaims: “Look! A chimpanzee!”. While I would take the comment as a compliment (chimps are awesome), I imagine many people would take offense at the gross error our feathered friend just committed. The other pigeon who was obviously paying attention in biology class would say: “No dummy, chimps have a lot more hair and don’t walk upright like that and they have longer arms and are much better looking. Yes, they are both primates, but can’t you tell them apart?”

So for the sake of not offending anyone, next time you see a harvestman (order Opiliones), take good care not to call it a spider (order Araneae).

After reading this article, this should be easy.

Both spiders and harvestmen are Arachnids (remember Arachnids, unlike insects, have eight legs and no wings), but despite appearances, they are quite different. Perhaps one of the best ways to tell them apart is that a spider’s abdomen and head (or cephalothorax) are clearly two different body parts. Harvestmen have both body parts as well, but they appear as one unit, one solid block.

How many pairs of eyes does a spider have? I know you know the answer: four.

Harvestmen however are just like you and me; they have one pair of eyes. Some of you are thinking, “It doesn’t matter, just like spiders they are venomous and even more dangerous!” That is a classic urban legend. Unlike spiders, Opiliones do not have venom glands and their jaws are usually too small to cause humans much harm.

That means harvestmen and spiders don’t have the same eating habits.

Opiliones are omnivorous, consuming plant material, insects, other arachnids and even slugs or snails. Just like Grandpa Bob who is waiting for his new set of teeth, spiders are on a liquid diet. They must inject digestive enzymes to liquify their prey before eating (fortunately, Grandpa Bob just uses the blender). The harvestmen, like the rest of us, eat solid food.

Why the name harvestman?

Most Opiliones species come out and wander in late summer or fall, harvest season, for mating. Thanks to iNaturalist, we know that this is not true for the genus Eurybunus. They are observed roaming the trails of our park in the spring, as in this observation by ncy5000: inaturalist.org/observations/79603762.

You’ll recognize these harvestmen by their solid black bodies and their long black legs adorned with white stripes. Think of them as little skunks. A stretch you say?

Well, how about the fact that just like skunks, harvestmen are able to stink up the place by releasing secretions via pores located at the base of their front legs. If after that a harvestman is still pursued by a predator, it can drop a leg which will keep twitching to distract the assailant long enough for an escape. Unlike lizards who also share the same behavior called autotomy by dropping a bit of their tail, harvestmen can’t regrow their legs. They can however continue to live their lives with a slight seven-leg handicap.

Harvestmen are commonly called daddy longlegs, a term I prefer to avoid altogether since it also refers to other animals such as cellar spiders (those long-legged spiders that like to visit your tub or shower) or crane flies (also called “mosquito eaters”, even though they don’t eat mosquitoes… that’s for a different article).

Editor’s note: Article provided by Patricia Simpson, a trail guide at Mission Trails Regional Park. Photo of harvestman by ncy5000 with a CC-by-NC 4.0 Creative Commons License.