Help me identify my new spider friend.

March 20, 2009 3:42 PM

Help me identify this black spider.

My kids and I been identifying the spiders we find around the house, for fun. I only have one field guide, and need a decent magnifying bug box, which makes things hard.

Right now, trapped under a glass in my kitchen, I have a round-bodied black spider a bit more than 1/4 inch long (body, not including legs). It was hiding in a vacuum cleaner's crevice tool that had been lying undisturbed on the basement floor for awhile.

The Black Widow in my guidebook is the closest match: the spider has a round body, long arched (rather than flattish) legs. In profile, it really does resemble this Black Widow , but it either has no markings on its belly or a very very faint dark reddish-brown stripe, which I might be imagining.

When it feels threatened, it rolls into a little ball. For awhile, it was hanging by a thread from the bottom of the upturned glass, with its legs pulled in tight. It seems very shy.

I've googled around, but can't find any images of other all-black spiders besides the Black Widow, except the False Black Widow, which isn't supposed to appear in my area (I'm in mid-Michigan).

I was not able to get a decent picture with my point-and-shoot camera. I'd like ideas about what it might be, though.

Any thoughts, from more experienced arachnophiles?

posted by not that girl to pets & animals (12 comments total)

So you have no pics, no real description besides:

-round-bodied black spider a bit more than 1/4 inch long (body, not including legs)

-it either has no markings on its belly or a very very faint dark reddish-brown stripe, which I might be imagining.


So its black and is shy (when trapped under glass). Hmmm...it could be any of thousands of spiders.

If I were you, I'd either:
1. Get a good picture (somehow), and let it go.
2. Just let it go.
posted by hal_c_on at 3:54 PM on March 20

hal_c_on, could you name a few? or a family? Or point me to a list of the "thousands"? My field guide, and guides on-line that I've found, do not offer many options for all-black spiders.

When released from the cup, it immediately runs to the nearest crevice-like spot; since it's on a kitchen counter, along the edge of the lip of the sink is popular. It doesn't jump, run toward me, or run away, all things that some spiders do. So it is shy when not trapped under glass as well.

I don't have sufficient magnification to see the arrangement of its eyes.
posted by not that girl at 4:03 PM on March 20

One way that it resembled the black widow is that it has highly-arched legs, rather than the flatter profile of, say, a nursery web spider. It also has relatively smooth legs, rather than being one of your more hairy-legged spiders.
posted by not that girl at 4:11 PM on March 20

My guess is male black widow, but they don't look THAT much like the females.

As hal_c_on says, it's really impossible to figure out without a photo.

Good Luck and good show fooling around with your kids like that! When I was just a pup and started bringing stuff home in margarine containers my folks bought me some books to help me recognize what was or was not OK to catch. I can't count how many times that's saved me from horrible bites, stings and worse.

Sorry for rambling!
posted by snsranch at 4:18 PM on March 20

My yard guy says: Not a black widow, and he can't remember its name, but it will cause a bad ra bites.
posted by not that girl at 4:26 PM on March 20

"Cause a bad rash if it bites."
posted by not that girl at 4:26 PM on March 20

How about this Australian one?
posted by b33j at 4:29 PM on March 20

I would try googling for spiders that are common in your area...I would check it out, out of curiosity, but I'm not sure where the rust belt is!
posted by snsranch at 4:32 PM on March 20

it might not be shy, but thirsty. apparently when spiders are dehydrated, they can't extend their legs. put the glass over a droplet of water and see what happens.
posted by klanawa at 5:00 PM on March 20 [1 favorite]

klanawa, your idea is great! but the spider has been released into the wild.
posted by SomePerlGeek at 6:19 PM on March 20

Black Widow webs are very sticky and noticeably tougher to dismantle than nice spider webs.
posted by auntbunny at 9:59 PM on March 20

Have you tried bugguide?
posted by AV at 11:37 AM on March 21