Work songs composed to keep rhythm during labor can be found around the world. Credit: Frank Perry / AFP via Getty Images Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. A few years’ back, a viral trend overtook social media that nobody saw coming: ShantyTok . Seemingly overnight, TikTok and Instagram were inundated with posts celebrating the niche world of maritime sea shanties. The fad ostensibly began with the spread of Scottish singer Nathan Evans ’ version of “Wellerman,” a New Zealand whaling shanty with historical roots stretching back well over a century. As newcomers dove into a vast backcatalog of songs, many quickly highlighted just how catchy these tunes really are. But while early sea shanty composers didn’t envision ever reaching the top of the charts, they certainly wrote them to be earworms.…