When fire ants encounter water, they will clump into a floating raft. But the individual ants don't always stick together in a tight blob - instead, some will throw themselves over the edge of the swarm to form tentacle-like protrusions.
But why do these individual ants purposely endanger themselves like that?
The Smithsonian explains:
“[The swarm] is almost like a smart system,” says Franck Vernerey, a soft matter physicist at the University of Colorado, Boulder, and the senior author of the fire ant study. “It's flowing by itself, producing those large, long protrusions and retracting them.”
Protrusion formation probably helps fire ants search their environment for new ground in a flooded environment, akin to casting a wide net and hoping something catches, says Linda Hooper-Bui, an environmental scientist at Louisiana State University.