At four months old, babies typically show remarkable growth and development, as seen with a baby weighing around 15 pounds and demonstrating joyful giggles and frequent smiles. At this stage, many infants begin rolling both ways—from back to belly and belly to back—which is a key motor skill milestone indicating improving muscle strength and coordination. Sleeping through the night is a positive sign, with most four-month-olds still requiring one feeding of pureed food per day and continuing with around size 2 diapers. Sitting up independently for longer periods is emerging, often supported by wearing 3-6 month clothing to suit their size. Babies at this age also exhibit increased curiosity and enhanced fine motor skills, frequently reaching for and grabbing nearby objects, which supports sensory and cognitive development. Short naps lasting about 15 minutes indicate a growing but still fluctuating sleep pattern. Hydration remains important; babies typically drink approximately 4 ounces of fluids every 1.5 to 2 hours. Parents can encourage developmental progress by offering safe toys to grasp, encouraging tummy time to build strength, and maintaining consistent sleep and feeding schedules. Regular monitoring of growth, diaper size, feeding routines, and awake times helps in tracking healthy development. If any concerns arise about milestones like rolling, sitting, or sleep patterns, consulting a pediatrician is recommended to ensure the baby's well-being and support tailored care strategies.