By Susan Milius
Colonies of Argentine ants spreading around the world might be real-life invasions of the living dead.
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2009/05/10334.jpg?resize=300%2C218&ssl=1)
Normal, still-breathing adult workers carry chemicals signaling “Dead ant — haul to burial pile” on their outer covering, proposes Dong-Hwan Choe of the University of California, Riverside.
What prevents awkward mistakes about who’s really dead are two additional compounds also found on the covering of living ants, Choe suggests. These compounds temporarily inhibit responses to the death cues by signaling, “Wait — still alive so far,” Choe and his colleagues report online May 4 in Proceedings of the National Academy of Sciences.