---
title: "First kiss was 20 million years ago by early primates, scientists say"
description: "AMSTERDAM, Nov 19 (Reuters) - Kissing did not begin with star-crossed human lovers but with the primate ancestors of great apes around 20 million years ago, according to a study published on Wednesday."
type: "NewsArticle"
publisher: "Daily Maverick"
site: "https://www.dailymaverick.co.za"
section: "Newsdeck"
author: "Reuters"
author_url: "https://www.dailymaverick.co.za/author/reuters/"
canonical_url: "https://www.dailymaverick.co.za/article/2025-11-19-first-kiss-was-20-million-years-ago-by-early-primates-scientists-say/"
published: "2025-11-19T04:40:08"
updated: "2025-11-19T04:40:10"
lang: "en-ZA"
word_count: 279
---

# First kiss was 20 million years ago by early primates, scientists say

> AMSTERDAM, Nov 19 (Reuters) - Kissing did not begin with star-crossed human lovers but with the primate ancestors of great apes around 20 million years ago, according to a study published on Wednesday.

By Reuters · Published 19 November 2025, 06:40 SAST · Updated 19 November 2025, 06:40 SAST

## Key points
- In a groundbreaking study that could make even the most passionate of romantics blush, researchers have traced the origins of kissing back to a time when our primate ancestors were more focused on lip-locking than lip-smacking, revealing that this age-old practice likely began between 21.5 and 16.9 million years ago, long before it became a popular method for spreading germs and assessing mate suitability.
- Researchers from Oxford and Florida Tech trace the origins of kissing to 21.5-16.9 million years ago, suggesting it stems from a shared ancestor of primates.
- The study defines kissing as non-aggressive, mouth-to-mouth contact, encompassing both sexual and platonic forms.
- The reasons for kissing's evolution remain debated, with theories ranging from mate assessment to social bonding.
- Evidence indicates that Neanderthals and early humans likely engaged in kissing, as they shared oral microbes long after diverging.

## Content

By Toby Sterling

Researchers from Oxford University and the Florida Institute of Technology wanted to examine when kissing began, given that from an evolutionary standpoint it has no obvious survival benefit, and could spread disease.

Yet humans, chimpanzees, bonobos, orangutans, and gorillas all kiss, which strongly suggests the habit was inherited from a shared ancestor. Scientists in the study combined observations of primate behaviour with data on evolutionary relationships, to rewind the clock and try and date the first kiss.

"Using these two key pieces of information, we employed a modelling approach that allowed us to simulate different evolutionary scenarios," said lead author Dr. Matilda Brindle of Oxford's Department of Biology. Running the model millions of times put that first smooch at 21.5-16.9 million years ago.

The findings were published in the journal Evolution and Human Behavior.

The scientists' unromantic definition of kissing was "non-aggressive, mouth-to-mouth contact that did not involve food transfer." This included sexual kissing as well as platonic kisses such as those between family members or in friendly greetings. How kissing emerged remains a subject of debate, as does why it persisted.

"Some people suggest sexual kissing is a useful way of assessing mate quality or suitability," Brindle said. "Alternatively, kissing could be a type of foreplay, increasing sexual arousal and boosting the chance of fertilisation."

Platonic pecks are thought to be used to navigate complex social relationships or increase bonding, she said.

The study argued Neanderthals and humans also likely locked lips, given evidence that they interbred and shared an oral microbe - a sign they swapped saliva - long after the two species diverged 450,000-750,000 years ago.

(Reporting by Toby SterlingEditing by Alexandra Hudson)