Striking to see this evolutionary step in comparison to other species.
You'll find mother-infant kisses across various primates! An obvious reason is that monkeys, and apes in particular, have fleshy lips they may also use for e.g., object manipulation (see Iwasaki et al. 2019). You may also be interested in the work on comparative lip microanatomy by Rogers et al. (2009).
The reason why humans don't lick their infants, however, likely involves the transition away from the ancestral chimpanzee-like tongue, which has more degrees of freedom outside the oral cavity - as opposed to ours, which has more degrees of freedom inside the oral cavity (Takemoto, 2008). In general, human evolution has de-emphasized the tongue in object manipulation (and emphasized it in articulation, i.e., speech). This transition may have been fascilitated by changes in diet, the introduction of which largely coincides with substantial changes to facial anatomy in the homo fossil record (Wrangham, 2009; Lieberman, 2011), and technological innovation of tools as indicative of greater capacities of planning (Osvath & Gärdenfors, 2005) and as a further de-emphasis of oral anatomy in object manipulation.
Refs:
-Iwasaki, S. I., Yoshimura, K., Shindo, J., & Kageyama, I. (2019). Comparative morphology of the primate tongue. Annals of Anatomy-Anatomischer Anzeiger, 223, 19-31.
-Lieberman, D. (2011). The evolution of the human head. Harvard University Press.
-Osvath, M., & Gärdenfors, P. (2005). Oldowan culture and the evolution of anticipatory cognition. Lund University Cognitive Studies, 122, 1-16.
-Rogers, C. R., Mooney, M. P., Smith, T. D., Weinberg, S. M., Waller, B. M., Parr, L. A., ... & Burrows, A. M. (2009). Comparative microanatomy of the orbicularis oris muscle between chimpanzees and humans: evolutionary divergence of lip function. Journal of anatomy, 214(1), 36-44.
-Takemoto, H. (2008). Morphological analyses and 3D modeling of the tongue musculature of the chimpanzee (Pan troglodytes). American Journal of Primatology: Official Journal of the American Society of Primatologists, 70(10), 966-975.
-Wrangham, R. (2009). Catching fire: how cooking made us human. Basic books.
That is becouse we have alternative for cleaning of infant. But due to evolutionary instinct to smell and taste there infant the concept of kiss is still in practice
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts