While there are some exceptions (like the echidna and platypus), most mammals rely on their mother's milk for nutrition during their early development. Milk provides essential nutrients like:
* Proteins: For growth and development
* Fats: For energy and insulation
* Carbohydrates: For energy
* Vitamins and minerals: For various bodily functions
This milk provides all the necessary nourishment for the young mammal to grow and thrive until they can start eating solid food.