Take a fire ant—don’t forget your gloves. Toss it in water, and it’ll eventually ___1___. But throw a group of fire ants into the water, come back the next day, and they’ll still be floating.

Ants are known for ___2___. A species of fire ant called Solenopsis invicta originated in the rainforests of Brazil. It adapted to the region’s frequent flooding by building rafts—made up of big groups of the ants themselves. These allow the ants to float, sometimes for months.

Scientists wanted to know how. They collected fire ants from roadsides in Georgia. They placed the ants in water in groups of 500, 3000, and 8000. The ants quickly group together. Half ___3___ underneath in a single layer—but there are small pockets of trapped air that likely prevent them from drowning.

The ants connect by gripping each others’ mandibles and claws. The scientists say it’s similar to ___4___ waterproof fabric. The resulting two-layer raft is cohesive, buoyant and water-repellent. The research was published in the Proceedings of the National Academy of Sciences. [Nathan Mlot, Craig Tovey, David Hu, Fire ants self-assemble into waterproof rafts to survive floods]

This discovery could help roboticists interested in building self-assembling flotation devices. Or just satisfy our curiosity about how ants cooperate to ___5___.
【视听版科学小组荣誉出品】
drown cooperative behavior get stuck weaving stay afloat
手套戴戴好，然后把一只火蚁扔进水里，你会发现这只火蚁终将溺水身亡。不过，你要是抓一大把火蚁扔进水里的话，第二天再来看，它们还在水上飘着呢，死不了。 蚂蚁齐心协力可是出了名的。红火蚁原产自巴西热带雨林。为适应当地多雨气候，它们制造出了小筏，而筏身则是它们自己——大批大批的红火蚁。借此，它们可以漂浮生存，有时候一漂就是几个月。 科学家们想对此一探究竟。他们从乔治亚州的路边收集来许多火蚁，然后把这些小家伙分成500只、3000只、8000只各一组，并分组放入水中。这些火蚁迅速集结起来，一层上面其中一半的火蚁还是会身陷窘境，不过一些小气泡也许是帮助它们免受溺水之苦的救星。 火蚁通过互相紧抓下颚和脚以保持紧密聚集。科学家们称，这就像是在织防水衣。火蚁制作的双层筏子够结实，漂浮性好，还防水，真是太美好了~该研究结果刊登在《美国国家科学院院刊》上。 这项发现也许能激起机器人研发人员对开发自主组装漂浮设备的兴趣，又或者只是满足了我们对蚂蚁集体漂浮的好奇心╮(╯▽╰)╭