Why can ants walk up walls?

[tubagirl]

I was watching ants while smoking when I realized,

“Why can they walk up walls and across ceilings? And why when I try walking up a wall on my hands and knees, I can’t?”

I realize that ants don’t have suction feet, so does it have to do with the gravitational pull of the earth and their small size in relation?

[ricepad]

What were you smoking?

[DSYoungEsq]

Scale and size, Tubagirl. You can walk up a wall if provided with crevasses and projections equal in scale to your fingers and toes as the ones an ant uses. I would suspect some aspect of it has to do with the ratio of weight to strength of an ant, also, but I’ll leave discussion of that to those with info.

Also, I think this belongs in General Questions. Where IS that moderator…

[C_K_Dexter_Haven]

Agreed, and now it’s in General Questions.

[Ukulele_Ike]

Not EVERY ant can climb walls.

Only those who’ve been bitten by radioactive spiders.

[PRISM02]

Ants can climb walls for two reasons: (1) the ‘smooth’ walls are not all that smooth because they have microscopic bumps and crevasses. (2) the ants have little hooks on their feet designed to grip in and on these little irregularities.

The same goes with flies.

[tomndebb]

Each leg always consists of five parts: a coxa articulated to the thorax, a small trochanter, a femur, a tibia, and a tarsus with one to five segments. The tarsal segments often carry claws with adhesive pads between them (arolia or pulvilli); these enable the insect to hold onto smooth surfaces. The legs may be modified for leaping, burrowing, grasping prey, or swimming in various ways.

(italics mine) from:
insect Thorax

(This was not straightforward look-up. The EB article on ants does not discuss their feet. I did a web search on “ant feet” and on one hit found a reference to arolia. I came back to EB and looked up arolia. There was no article on it, but the search did turn up the reference in the section on insect thorax.)

[Phobos]

*Originally posted by tubagirl *
**so does it have to do with the gravitational pull of the earth and their small size in relation? **

The others answered your main question, but I’ll just note that gravity doesn’t work any differently for ants than for us. It’s just that the adhesive/hooks on the ants’ legs certainly don’t have to support much weight.

[foolsguinea]

Also, there’s some structural advantage to being tiny. The amount of muscle required to move an ant’s body vertically is pretty small, and the stress on the wall’s structure is very little. In fact, due to gravitational effects, I’m not at all sure a creature structurally identical to an ant, but weighing 50 pounds or more, would be able to scale walls without adding a lot of muscle mass. And I know such a critter would be hard on the plaster walls in my house!

[tracer]

Hey, yeah! Why do we never see Spiderman falling off walls or ceilings with plaster stuck to his hands?

[Smeghead]

*Originally posted by foolsguinea *
**Also, there’s some structural advantage to being tiny. The amount of muscle required to move an ant’s body vertically is pretty small, and the stress on the wall’s structure is very little. In fact, due to gravitational effects, I’m not at all sure a creature structurally identical to an ant, but weighing 50 pounds or more, would be able to scale walls without adding a lot of muscle mass. And I know such a critter would be hard on the plaster walls in my house! **

They wouldn’t even be able to stand up. They’d collapse under their own weight. Exoskeletons aren’t very good at our size.