When a toddler bites nails, the habit may appear during quiet moments, waiting, screen time, stories, or changes in routine. Nail biting can be connected to boredom, comfort, imitation, or a rough nail edge and does not automatically indicate anxiety. This guide explains how to observe patterns and respond calmly with short, smooth nails, gentle hangnail care, safe activities for busy hands, and quiet reminders. It also covers what parents should avoid and when pain, bleeding, damaged skin, swelling, pus, changes in nail growth, significant distress, or signs of infection should be discussed with a healthcare professional.