Guided by evolution, most species protect their young and let older ones die off in a crisis—right? Not in the case of ants, according to a study in PLoS One. When water washes out an ants' nest, the vulnerable larvae and pupae become life rafts, and queens are allowed to ride in the center. That puts the babies at risk of drowning, cold, and predators lurking underwater. But ants have a reason for such callous escape methods: Their little ones float better, the International Science Times reports.
Ants aren't alone in putting their children at risk: Bees are known to toss out larvae infected with infectious bacterial disease, and Time reports that mustached tamarin mothers, when overwhelmed, will kill their own kids or let them die off. The scientists who studied ants in controlled floods found that the babies were usually just dazed after being life rafts, and walked off no worse for wear. But conditions may be worse in the wild, they note, thanks to "oxygen deprivation, increased CO2 levels, and possible thermal effects from cold water." (Read more ants stories.)