The period of time when young animals grow to maturity is commonly referred to as "juvenile development" or simply "development." This stage varies significantly among species, but typically includes several key phases, including infancy, adolescence, and maturation. During this time, juvenile animals undergo physical and behavioral changes that prepare them for adult life, which may include learning to hunt, build shelters, or find mates. Growth rates and the length of this developmental phase can differ; for example, some species mature quickly, while others, like elephants, may take many years to fully develop.