Spiders, or at elast a great many of them, have eight eyes. (Some have fewer.) Other arachnids have way too many eyes as well - scorpions have multiple eyes, some as many as 12. Some arachnids have no eyes at all.
I thus have two questions:
Is there any other class of creatures that can’t agree on how many eyes they should have? For that matter, are there any other creatures with more than two eyes? (I count a compound eye, like a fly’s eye, as one eye.)
Since I own about a dozen tarantulas and scorpions, I shall try to tap into my vast knowledge of arachnid husbandry to help you in your quest for knowledge.
Well, every vertebrate and almost all invertebrates have two eyes or two globs fo compund eyes (one possible exception being the tuatara, a reptile with a third pseudo-eye, but they don’t really count). For the life of me, I can’t think of any insects that have more than two sets of compound eyes, except for those that have no eyes at all.
Because they’d look really silly with nine.
For most spiders, the two “main” eyes in the front are for primary sight with a very narrow field of vision, while the others arranged around thier heads perceive only light and dark, giving them some degree peripheral vision. Of course, it all depends on the spider. Jumping spiders and wolf spiders have pretty darn good vision, but from my experience, though, those eight eyes don’t seem to do my tarantulas a damn bit of good, since they don’t seem to respond to anything visually. Why they have eight and not, say, six, is just one of those mysteries of nature I suppose.
I don’t know off hand how good other arachnids’ vision is, although my scorpions are likewise very poor at understanding semaphore signals.
Most insects actually have three simple eyes (ocelli) in addition to the two large compound eyes, usually situated between the compound eyes. A spider’s eight eyes are similar to the simple eyes of insects. The number and placement of an insect’s simple eyes are quite variable, and some lack them. So an insect’s eyes can vary in number from two to five (counting the compound ones as single eyes).
It all started many years ago out of a desire to freak out my mother. As I think back now, it seems that most of my life to that point had centered around driving my mom to the loony bin, and to some extent it still does, but that purchase of a tarantula was the beginning of a new hobby.
In many ways, tarantulas are the perfect pets. They aren’t noisy, they don’t smell, they can live for months without food or water, they don’t need to be petted, they don’t need much room, they don’t shed all over the furniture, and finally, their poop is very small. Granted, it may seem to many that I’ve gone a little overboard, but there are so many different varieties out there. In some ways its as wholesome and American as collecting stamps or baseball cards, only with more legs.
Since the don’t like to be held, they’re mosty for display. Some are amenable to handling, but others don’t care for it at all and let you know it. I’ve never been bitten, and even if I were, tarantuals aren’t dangerous to people anyway.
Here is a link to my page where I list the tarantulas and other things I own. It’s in DIRE need of an update, since I’ve acquired some new ones recently. http://www.geocities.com/heroic665/pets/
I buy them all as spiderlings so I can indoctrinate them early on to form the backbone of my arachnid army.
Hey! I’m not a sissy! Bravely, and with utter confidence, I entered your leggy web site. My ultimate assessment: those are some serious looking spiders. If I was forced to like one, it would have to be the itty bitty one, back when it was itty bitty, though Raca was…attractive? I’m glad that one spider didn’t drown. (That was a bit scary there for a moment!) But, I do want to know how and why they can molt a leg off. That’s seems to be poor design. Anyway, I did have to stop after the first scorpion cuz I, apparently, am a big sissy.
I’m not exactly sure how it happened. I reckon that because Anansi inadvisedly decided to molt in an enclosed area, the struggle to get loose of the skin may have detached some legs. Very sad.
Molting is definitely the most dangerous time for a tarantula (or any arthropd) since they can’t move while they’re doing it and are soft for quite a while afterwards. Worse, if they don’t dry right, they can have possibly fatal deformities of the fangs.
That said, 99% of the time if goes off without a hitch. It’s a hell of sight to watch them “shrugging” out of their skin. I wish I could catch it on film. They always do it when I’m not around.