How long ago was the first human-on-human smooch? It depends how you define a kiss
The Independent - Science •
With the exception of a few species, and most apes and a handful of monkeys have been observed to kiss
The first human kiss originated 21 million years ago, study finds
The Independent - Science •
Kissing Has Existed for at Least 16 Million Years, Scientists Say
The New York Times - Science •
