4 Reasons Babies and Toddlers Suck Their Thumbs

If you’ve ever watched a toddler with a thumb in their mouth, you might have wondered why they do it. Thumb sucking is a normal behavior in early childhood, and it happens for several good reasons. Most kids naturally outgrow the habit as they get older, but understanding what drives it can help you support your little one through this phase. Here are four reasons babies and toddlers suck their thumbs.

Hunger or Oral Exploration

Babies explore the world through their mouths, and thumb sucking is a significant part of that discovery process. In the early months of life, your baby may suck their thumb when they’re hungry or looking for something to do with their mouth. This oral exploration is how they learn about textures, tastes, and sensations.

Most babies start sucking their thumbs at birth and continue doing so until they’re around two to four years old as they move through the oral development stage. Using their mouths to explore helps children build neural pathways related to taste, texture recognition, and hand-to-mouth coordination.

Self-Soothing and Comfort

Thumb sucking is a normal behavior in early childhood, and it happens for several good reasons. In fact, many psychological theories explain self-soothing behaviors like thumb sucking, showing how they help toddlers manage stress, regulate emotions, and feel in control.

If your child sucks their thumb to relax, you may notice that they often do it after a tantrum, during a long car ride, or when they’re settling into a new environment. The repetitive motion and familiar sensation give them a sense of security, which is why you’ll often see them reach for their thumb when they need to feel safe.

Sleep Aid

Many toddlers suck their thumbs to help themselves fall asleep. The rhythmic motion and soothing sensation create a calming effect that makes drifting off easier. You might notice your child reaching for their thumb as part of their bedtime routine or during naps. Over time, this habit can become a sleep association, which means they rely on it to feel ready for rest.

If your child is around the age of four, you may have to help them adopt new sleep routines, as thumb sucking should end around this age. Try pairing bedtime with other comforting activities such as reading a story, playing soft music, or giving them their favorite stuffed toy. The goal is to find a new coping skill that helps your child feel relaxed and safe so they can drift off to sleep.

Boredom or Habit

Another reason babies and toddlers suck their thumbs is simply because it’s become a habit for them, done without much thought. In this case, it doesn’t always relate to a specific need like hunger or stress; instead, it becomes a part of their routine. This type of thumb sucking can fade with age, but some children get addicted to the dopamine release and need help quitting.

If the habit continues past age four or five, or if you notice dental concerns, it’s a good idea to check in with your pediatrician or dentist. Until then, try to view thumb sucking as a normal and natural way for your child to self-soothe and feel secure.