Amazing ants ‘fly’ when they fall

Look, ma, no parachute!
The falling ants’ first phase is called uncontrolled parachuting because they splay their legs in all directions in an effort to slow their fall by increasing drag. However, parachuting animals technically lack control over their trajectory.

Gliding or directed descent is initiated in phases two and three when the ants turn around and gain control over their flight path.

Their typical falling speed is 8 mph (4.3 meters per second), a fast clip for a creature less than a half-inch (1 centimeter) long. Sometimes, the tiny creatures bounce off the tree trunk the first time they hit it. When that happens, they're able to recover control rapidly and glide right back to the tree, Yanoviak said.

For arboreal animals, the ability to glide or fly or even parachute can be a life-or-death matter. Ants are frequently buffeted about by the wind or nearby mammals and birds, which can knock them off a branch or leaf to start tumbling down to a risky place — the forest understory, comprising the shrubs and trees that grow between the rain forest canopy and the ground cover. Moreover, some ants will voluntarily drop off tree trunks when approached by a foreign object.

In any case, the ability to self-rescue comes in handy. The understory and forest floor are full of hazards, not to mention terrain that is tough for tiny navigators, Kaspari said.

"An ant falling to the forest floor enters a dark world of mold and decomposition, of predators and scavengers, where the return trip is through a convoluted jungle of dead, accumulated leaves," Kaspari said. "Gliding is definitely the way to go, and we won’t be surprised if we find more examples of this behavior among wingless canopy insects."

Gliding is thought to be an important stage in the evolution of flight, scientists say.

Major trip
A fall of 30 yards is a huge distance for a canopy ant — 3,000 times the animal’s body length. For a human, this would be equivalent to being tossed 3.5 miles and then having to walk back home (although humans have different biomechanics and energy reserves that ants lack).

Ants often rely on chemical trails to find their way back to the nest. If they land in the understory and cannot find a trail or some other cue to get home, they are lost forever. Like many animals, ants are dependent on the work and contributions of the entire group, so the loss of any individual ant that falls and never returns is costly.

For this reason, evolution has favored traits like sticky toes and the ability for directed aerial descent to prevent the loss of workers, Yanoviak said.

The ants glide backwards because their hindlegs are longer than their forelegs. It is probably easier for them to get a quick grip on the tree with their hindlegs, as if using a fishing gaff or grappling hook, Yanoviak said.

It could also be that the shape of an ant's body only permits directional control in the air when facing backwards. However, Yanoviak said he recently discovered a type of ant called Camponotus that glides to the tree head-first. "The story will undoubtedly get more interesting the more we work on it," he said.

Other arboreal creatures that can glide include lizards, frogs and snakes. Still no word on whether pigs can fly.

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