It’s well known that chimps and bonobos have much larger overall genitalia size than humans, but most people think this is only because of their colossal testicular size (triple that of humans).
However it seems that chimps also have longer penises than non-African humans, and bonobos have much longer penises than all human races!
According to an article in Psychology Today, bonobos have an erect penis length of 6.8 inches, followed by chimps at 5.8 inches.
By contrast, human racial data found by commenter Afrosapiens shows peoples of African ancestry averaging an erect penis size of 5.81 inches, followed by whites at 5.71 inches, and East Asians at 5.08 inches (though it’s worth noting that human penis size data is notoriously unreliable)
So even before adjusting for their much smaller heights, our closest ape relatives have far bigger male genitalia than most humans do, both in testicle size and in penis length. Though humans have thicker penises.
Sex is such a dominant part of human life that it’s fascinating to think that our closest ape relatives (with triple our testicle size) experience triple our sex drive. Despite having an average IQ of only 14, they probably wouldn’t trade places with humans because it would mean giving up a sex life so intense and extreme, us humans can’t even imagine it.