Why Does That Baby Macaque Always Suck its Thumb? The Nature of Thumb-Sucking in Pet Macaques

I wanted to delve into the issue of digit sucking in pet macaques, as this is so prevalent across social media pet monkey channels. The issue of thumb sucking in pet macaques appears to be multifaceted.

Question
Why do wild macaques not engage in sucking thumb-sucking like pet macaques do?

#️⃣babymonkey #️⃣macaques