A lion's roar doesn't tell you much about whether an animal is a king of the jungle, or a joker.
A lifetime of Disney movies has trained me to have certain expectations about animal sounds, most especially with regard to the King of the Jungle, the lion. The best lion has the best roar. Them's just the rules.
But now, courtesy of Ed Yong's eagle eye, we have scientific evidence that a lion's roar says very little about an animal's role in the jungle's hierarchy. A team analyzed the roars of 24 lions collected over decades in an effort to discern whether there were meaningful correlations between the features of the roar and the animal's sexual fitness.
"No evidence that acoustic variables were related to male condition was found, indicating that sexual selection might only be a weak force modulating the lion's roar," the researchers concluded in a 2007 paper.
The vocalizations of the male lions were not highly correlated with other characteristics either, not even how nice and shiny (and dreamy!) his mane is.
"The acoustic features of male roars neither varied with mane color nor with mane length," they wrote. "Both mane color and mane length are signals of male status and have been characterized as costly signals, because larger manes and darker hair increase the surface temperature and decrease the rates of heat transfer, which can harm sperm production."
About the only thing the researchers could tell from was whether the lion was a male or a female. The smaller females roared with a slightly higher fundamental frequency (195 Hz versus 207 Hz).
The researchers do have another theory about what a lion's call signals: "Lion roars may have mainly been selected to effectively advertise territorial boundaries," the paper speculated. Not come hither, but step off.