Various ant species do a similar thing where their soldiers have really big, flat heads and when their nest gets attacked, the soldiers stick their head into the entrance way, so the attackers can't come inside.
Apparently, this kind of behaviour is referred to as phragmosis.
Thank you America for growing your population so large. When climate change gets so bad that the dykes pop, we can just grab the nearest American to plug the hole and save humanity.
Not OP, I couldn't find a paper. Just this site that makes the same claim almost word for word, and cites a youtube video of a lecture at Stanford. I didn't watch the video, but this seems best described as a "plausible" explanation rather than a proven fact.
Shit! That video is Robert Sapolsky's lecture. I have something like an "intellectual" crush on him. He has done pioneering works in behavioural science, and at the intersection of human physiology and psychology. One of his books "Why Zebra's Don't Get Ulcers" is entirely on the various effects of psychological stress on the human body.
He observed the same group of baboons for 25 years to understand their behaviour. Each year he used to spend 4 months with this group and observe them for more than 8 hours a day. "A Primate's Memoir" is another book on this. Recently he wrote "Behave", on the deterministic nature of human behaviour, tracing "aggression" back to the evolutionary reasons.
The more I read about them, the more I'm fascinated with how alien they seem to be to me. It's either them or crabs as the ultimate form that everything would come to eventually. Maybe even molecrabs we are yet to discover.
Naked mole rats are considered an example of a truly "eusocial" mammal analogue to ants. More evidence for the idea that social behavior/societal grouping, once established in a species, characterizes it more potently than just about anything else in its genetic history. Chimps might be our closest genetic relatives, but the way we live and think is probably much more similar to these guys.