Final answer:
Mammals are dependent on their mothers for food until they are weaned. The length of this period varies by species, and parental care often includes protection and teaching essential survival skills to the young.
Step-by-step explanation:
All mammals are dependent on their mothers for food until they are weaned, which is the process of transitioning from mother's milk to other forms of nutrition. This period of dependency varies across different mammal species. In most mammals, such as humans, kangaroos, and pandas, the offspring require considerable care and nourishment post-birth as they are relatively helpless. For example, the young grey kangaroo is completely helpless at birth and remains in the mother's pouch for about nine months before it begins to venture out. Furthermore, in species like meerkats, parental care includes not only feeding but also teaching valuable survival skills, such as how to safely eat scorpions without being stung.
While guinea pigs are an exception where the newborns can eat solid food immediately, they do drink milk if it's available. This underscores the importance of parental care in ensuring the survival of the offspring. This care takes various forms, from feeding and protection to teaching essential life skills, and is critical for species that produce fewer offspring and invest a significant amount of energy into rearing each one. The extent and duration of this care reflect the adaptative strategies of mammals in nurturing their young and safeguarding the species' continuation.