why these ants don't die?

i thought they were dead long back. i've not seen seen them for long, i mean since the last winter. in the midst of last summer i shifted to my present room, 29. it was full of these red ants then. every nook and corner of the room belonged to them. they considered me as an intruder and attacked me with their painful stings at every possible instance. i initially thought, what these little ants can do to me? but when they decided to claim my bed and computer table too, the latter of which disturbed me most, i declared war on them. my lobby servant, gopal - who like my mom used to when be i was back home - is so meticulous about the cleanliness of my room, told me they will remain this whole summer but would die as soon as the winter sets in.
the winter came soon (or rather, last summer was so eventful that it went very fast) and the ants slowly disappeared. i searched for them everywhere - they were not there , not even inside the switch-box (in fact, i opened that too....did i miss them, then?)
then came spring....summer...now its autumn...i had forgotten them by then. i was waiting for the monsoon, which arrived late this season, but with a bang...i know its grossly incorrect to call the rains here 'monsoon'; being a malayali (keralite) i should call these 'mango showers', the ones we get every afternoon during summer. yet, this time it was better than last time. like those mango showers, the monsoon showers here comes in the evening. but, its one of the most enjoyable moments you ever to get have in your life, particularly if you have decided to spend your life as a 'garshom' (did they have a choice, let Moses answer!), but had a childhood in one of those tropical paradises on earth.
but it was yesterday only that i noticed those ants coming out of a crevice in my supposed to be computer table. Omg, where were they all these days? now , where have they come back from? i donno? do you? if yes, please share....now, i'm in my friend's room ....i see them here too, he's also wondering-where these 'bloody' creatures 've come back from? he says, "i can't even leave a ............... on my table!".