Professors Chad Tillberg from Linfield College and Chris Smith of Earlham College and colleagues research the Dinoponera australis or dinosaur ant social structure. (Courtesy of Alex Wild/alexanderwild.com)

Turns out it’s not only among humans that the rich get rich and the poor work harder.

Researchers studying one of the world’s largest ant species — Dinoponera australis, the inch-long dinosaur ant of South America — dug through five of the ant’s colonies in Argentina, measuring the insects’ body fat and correlating it with what kind of work each specimen did. They found that the hardest workers, with the most dangerous jobs — the foragers — were the leanest. “The ‘working poor’ are the most nutritionally stressed,” said Chad Tillburg of Linfield College in Oregon. The fattest ants, with the most power, had cushy jobs at the center of the nest. “If we think of fat as a type of currency, we see that one group possesses a disproportionate share of the wealth,” Tillburg said. “These differences in wealth are associated with jobs.”