(if they are happy, they will not leave the jar, ever!)
Another ant story.
Won't be the last, I promise you. Because when I was little, I liked ants quite a lot. (I was an only child and I had no one to play with.) I had great fun catching them, keeping them and doing all the matter of cruel things that children do with ants. But this is one ant story that I always like to share with people.
Back when I was eight or nine, I live in a house where there were these half a centimeter sized orangy-red ants in the backyard. They weren't too small and they weren't too fast. They bite, but their pincers weren't sharp enough to penetrate skin, so they were quite harmless even in great numbers. I could catch them, nimble with my little fingers, by their little legs. And I would put them into transparent containers like jars, tic-tac boxes and lego constructs for observation.
One day I got hold of a glass jar (Peanut butter jar, it was if I recall correctly) and thought to copy something I saw in a book on how to keep ants. Usually, people who keep ants as pets, keep them in something called ant farms. These are glass tanks filled with soil. So I did this: first I filled the bottom of the jar with moist soil, just enough to cover the bottom. Then I threw in a few of freshly picked juicy-looking leaves from the park nearby, making it look cosy. Lastly I sprinkled in a bit of sugar. After this, I poked pin sized holes into the cap. And then I proceeded to get myself some ants. I managed about fifteen to twenty. It is possible to do them all in one go if you are fast and you're an expert like me.
Not surprisingly, at first, the ants ran frantically about all over the inside of the jar. A few lucky ones managed to escaped as I was putting another one in. (And a few brave ones tragically died trying to escape, squashed between cap and edge of the jar.)
After a while, the ants calmed down and stood about. Most of them were sitting near the cap, waiting, ready to dash out if I should be so foolish as to open it up again. I left them alone. The next day, a few ants were at the bottom, sucking at the sprinkled sugar, a few were just idling on the leaves. Some were still on the cap. This is where things became interesting. As days went by, more ants came down from the cap and were either on the leaves or on the soil or on the side of the jar. Eventually, only one or two ants were on the cap, the rest of the ants sat within the cosy tent of leaves. A week went by, and another. There were no more ants on the cap, they were either in the pile of leaves or dead.
Three weeks had gone by, my ants were still alive, which was surprising to me at the time. Their appearance had changed some what. They have very fat abdoments (well, the hind section). They were sitting together in the pile of leaves doing absolutely nothing. The leaves had become slightly curled, but was still green and quite lush. (I guess the moistness and humidity helped).
Little young me decided that it was time to let them go. I took off the cap and left the jar outside. ( I didn't want to pour them out roughly. )
The next day I returned and guess what. The ants were still there! Sitting there doing nothing. I took the jar and put in my room. I didn't cap it. They'd probably get out by themselves once they notice the jar no longer had a cap, or so I thought to myself. Another week went by, and not one ant left the jar.
I didn't get to know how long they would stay in there with the jar left open because mum found it and freaked out over the whole thing. (She threw the whole jar away 
. )My guess is that these ants would never leave. Why would they want to? Free food (sugar and probably leaf juice), a nice cosy nest and no queen to boss them around.