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 spider 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 Araniee 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 and are in a different order called Opiliones.
It was these I had it mind while making the video.
To make things more complicated, in my adoptive UK the british call this Crane Fly daddy long
legs.
Unlike the closely related Opiliones and Araniee 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 long legs.
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 the first question: there are four daddy long legs, three animals, two arachnids,
but only one spider among them.