Are Daddy Longlegs Spiders? (Re: 8 Animal Misconceptions Rundown)

In my animal misconceptions video, I casually mentioned that daddy long legs aren’t spiders and received a ton of comments asking for clarification or suggesting that it’s not that simple. So I feel the need to clear things up a bit. But first, a disclaimer: If images of spiders make you uncomfortable, 1) you shouldn’t have clicked on this video, and 2) you should stop watching, right about now.

Cutest spider ever. Right? When editing the video, I decided to cut out a daddy-longleg discussion, and now you’ll see why. To answer the question ‘are daddy longlegs spiders?’ we first need to know, what are spiders? And for that, we need the biological classification system you should have learned in high school.

Spiders are in the animal kingdom – which is a pretty broad class of life and not helpful in narrowing things down. The phylum that concerns us are the arthropods, which are a subset of animals with external skeletons, segmented bodies, and jointed limbs. The arthropods with exactly eight legs and two body segments are in a class called arachnids – where the name arachnophobia comes from.

And while often used to mean fear of spiders, there are plenty of arachnids that are not spiders, such as scorpions and mites. The true spiders are a subset of arachnids in the order Araneae. What defines these as spiders are their fangs and the poison glands within them, their numerous eyes, and their spinnerets that allow them to make webs.

Now that we have a spider checklist, on to the second problem: the name ‘daddy longlegs’ means different things in different places. In Australia, this cellar spider is called a daddy longlegs – which, as an eight-legged, multi-eyed, web-spinning member of Araneae, makes it an official spider. It also produces venom, but then so does everything in that bloody country.

Where I grew up, this is a daddy longlegs (sometimes called a harvestman). They have just two soulless eyes, can’t web-sling, and lack fangs and poison glands, and so fail the spider checklist. They are in a different order called Opiliones. It was these I had in mind while making the video.

To make things more complicated, in my adoptive UK, the British call this Crane Fly daddy longlegs. Unlike the closely related Opiliones and Araneae, the Crane Fly isn’t an arachnid but an insect, the class of arthropods with six legs and three body segments. And, as if the name wasn’t ambiguous enough at this point, there is also a plant called daddy longlegs.

For taxonomical completeness, the plant is over here a different kingdom. But because of the way life works, even this plant is distantly related to those other daddy longlegs because plants and animals are both eukaryotes, which means that their cells have complex structures, most notably a nucleus.

So, to fully answer the first question: there are four daddy longlegs, three animals, two arachnids, but only one spider among them.