LEDs light up spider eyes at 100 feet - wild!

[IdahoDoug]

I'm sure others have noted this and similar interesting effects from the short wavelength of LED lights but this was worth typing.

I just got home from a couple weeks in Florida and while there I played around with my Wolf Eyes Cree Explorer several nights. We were on an island and there's lots of jungle type conditions with swamps and little critters. One evening coming home from a night walk along the Gulf beach, I noted that I could sometimes get a tiny little pinprick of green brilliantly reflecting back at me from the grasses. I had always thought they were dew drops but I realized they were too far apart and infrequent on this night so I honed in on one about 100 feet away. I had to keep coming on the precise angle or it would wink out - stooping progressively as I got closer to the source. To my amazement, it was a common little spider's eyes. Tiny - no more than a half inch in diameter including legs - and sitting on a blade of grass. After that I grew more adept at it and was able to show others in my family how I could find a spider and other insects from very far off in the dead of night in tall grass or shrubbery. You just walk along until a tiny gleam or wink catches your eye and then home in on it as described.

So, another strange but fun character of LEDs to play with. It also works with tiny crabs and things but only closer. For some reason owing to the spider's role as a predator with appropriately effective eyes, they were visible from incredibly far off. Lots of fun..

DougM

 

[defloyd77]

If I remember my school teachings well, only a few types of spiders have a tapetum (the same thing cats and deer have) one of them being the wolf spider. It's really amazing that even my dim stylus with red led can light up a cats eyes 100+ feet away with ambient city light, quite an eerie effect if you're not expecting to see glowing red eyes. Great story.

 

[whippoorwill]

In the south we call it 'sniffing spiders', because as you said, the reflection can only be seen if you hit them with the beam dead on. Amazing trick to pull on the young kids. However, it is not just LEDS. I had been doing it for years before LEDS were even thought of.

 

[GadgetTravel]

When we were in Zambia a couple years ago we would go out night spotting in the National Park we were in. The guides had an uncanny ability to determine what an animal was by the location of the eye (tree, brush, etc) color/brilliance and spacing. I would see something and it would almost always turn out that they had already spotted it and discounted it, like just an impala or something.

 

[Sgt. LED]

It IS a very cool effect!

 

[light_emitting_dude]

Can't wait until summer here! It is an interesting thing to see!

 

[Hondo]

Yes, very cool, I discovered this too while walking out of the woods after hunting in 2006. Interesting I had not noticed it with incans before as whippoorwill said, but I spend a lot more time in the woods after dark since getting into LED lights, so that could have a lot to do with it.

I was then amazed at how many of the wolf spiders were just sitting about in my lawn. I can't remember for sure, but I seem to remember being able to do the same thing with the moths as well.

 

[Illum]

I've done this before, lighting up tall grass with LED light for spiders, this and that, usually helps me avoid walking into them [webs also appear after dew condensation]

the spiders doesn't seem to be angered, if they were I certainly didn't notice it

 

[cv3po]

Sweet! Come summer here in michigan I'll have to try that. My red-leg tarantula's eyes are too small to reflect light but any ground hunting spider (wolf, lynx or any species of jumping spider) have two large eyes in front and have excellent vision. Good stuff!

 

[PhotonWrangler]

...in other news, dozens of blind spiders turned up on an island in Florida recently... :laughing:

 

[txmatt]

This works best with a headlamp. The light from the animal's eyes reflects back along the same axis from which it came. The closer the light source is to your eyes, the more likely you are to see this reflected light.

 

[p1fiend]

Holy timing Batman!

Just this evening as I was leaving work, I was shining my P2D out across a neighboring field to see how far it would throw. All of a sudden I see 4 green eyes staring at me. I was freaked!!! I assumed they were deer (based on the height of the eyes). The light didn't have a chance of lighting up the bodies, but it made the eyes glow.

Pretty neat!

 

[greenlight]

It's called 'retroreflectivity'.

 

[Patriot]

In the south we call it 'sniffing spiders', because as you said, the reflection can only be seen if you hit them with the beam dead on. Amazing trick to pull on the young kids. However, it is not just LEDS. I had been doing it for years before LEDS were even thought of.

Yes, I've noticed that any light will work and Wolf-Spiders light up from a very long distance.

GadgetTravel
When we were in Zambia a couple years ago we would go out night spotting in the National Park we were in. The guides had an uncanny ability to determine what an animal was by the location of the eye (tree, brush, etc) color/brilliance and spacing. I would see something and it would almost always turn out that they had already spotted it and discounted it, like just an impala or something.

That's neat gadget. When I'm up archery deer hunting we go out spotlighting at night while we drive all of the roads. Within a short amount of time you can tell the difference between elk, dear, cattle, coyotes and others, just by the color, intensity of reflection, spacing and so on...all the things you already mentioned. It's funny because in short order you get really good at it. When buddies show up for the hunt during the following days and we take them spotlighting, they think that we're total "hot shots" because we've already discounted interest in an animal and while they're still trying to figure it out.

 

[IdahoDoug]

Good one on the blind spids - got a chuckle out of me.

This effect is not limited to wolf spiders - these were ordinary everyday grass spiders. I'll look forward to checking for a wolf spider's reflections. One spider was actually a very large one and at the right angle you could clearly see TWO eyes looking at you from some distance away. He was about 2.5 inches in diameter and I was not fired up on discovering they're in the grasses my children like to run through so I didn't tell them. They'd end up carrying one into the house.

As noted, this also works on other insects like moths but I didn't think you guys would regard "moth spotting" on the same manly level as spiders - heh. There's a greenish clear insect we call a "lace wing" that is kinda like a moth and their eyes are incredibly reflective and I think they're red. Kind of an eerie look for such a wimpy insect to have these fiery red eyes...

DougM

 

[Hondo]

Moth hunting not manly? First you catch a monster wolf spider in a jar, then hunt down a whopper moth to toss in there. Then it's showtime! Watch that sucker take down an insect many times his own size and feast on it. Even my two girls get in line to see that one!

 

[dcom]

I learned about spider sniffing in Boy Scouts back in the 70s, it's a fun thing to do with kids. As posted before, it works best to hold the light at your temple, even with your eyes. That technique is good for finding things like small jewels in carpets too.

 

[yellow]

it was a common little spider's eyes. Tiny - no more than a half inch in diameter

doh, at 1st reading I thought that was the size of the eye - got awake very quick

 

[Outdoors Fanatic]

I do that all the time, but I use a headlamp instead. Much more effective. You never miss the spider's eyes using a headlamp because the light follows your head and eyes.

 

[z96Cobra]

I did the same thing this past summer, also thought it was dew at first, then "remembered" we were in a bad drought and there was no dew. The second one I checked out had about 100 little baby spiders on its back! Really cool! Went and got the camera, but couldn't find any more with the baby spiders.

Roger