These Nomamyrmex esenbeckii. of army ants live in South America and are among the few species of ants that do not build nests, they link their bodies together to make a structure called the bivouac.
These ants are almost totally blind. While ants generally tend to have poor eyesight (though there are exceptions, such as Gigantiops destructor and many Myrmecia sp.) so, it's even more interesting that this species has chunky antennae.
What I've noticed is that ants that do a lot of fighting tend to have more study antennae-- and when it comes to violence? These girls are among the most belligerent ants on the planet! Being nomads army ants always stay on the move, they run through the forest in waves up to a meter wide driving all living things from the bush, killing and eating every insect they encounter. That's where they get their other name "driver ant" because they drive a wave of creatures from the forest! There are many species of "ant bird" that feed almost exclusively on the creatures chased from their homes by driver ants.
So, these girls are built for fighting and can't afford delicate breakable antennas -- (This was originally a response to someone who posted this photo and asked why their antennae are so chunky. But that person has deleted their blog. So, I've reconstructed it here. )