infants are defined as babies under one year old, while toddlers are children between one and three years old. The term “infant” typically refers to the period from birth to around 12 months, while “toddler” generally describes the stage from 12 months (1 year) to 36 months (3 years). Infancy (0-1 year): This stage is characterized by rapid physical and cognitive development, including learning to sit, crawl, and potentially walk, as well as developing language and social skills. The Ages and Stages for Newborns, Infants, and Toddlers Toddlerhood (1-3 years): Toddlers are characterized by increased mobility, developing language skills, and growing independence. They are learning to walk, run, and explore their environment more actively, while also beginning to communicate more effectively and assert their independence.