- Kissing started 20 million years ago, long before humans existed upi.com
- Study on origin of kissing traces it back to early primates RTE.ie
- First kiss dates back 21 million years, say scientists BBC
- Neanderthals also kissed: A gesture of love that is 21 million years old EL PAÍS English
- Neanderthals and early humans ‘likely to have kissed’, say scientists The Guardian
