Final answer:
Mammals have the longest juvenile period due to the extensive parental care they provide, which includes protection, feeding, and teaching skills necessary for survival. Mammals like humans, kangaroos, and pandas invest a great deal in a few offspring, requiring a long development before they become self-sufficient.
Step-by-step explanation:
Animals with the Longest Juvenile Period
The type of animals that have the longest juvenile period are typically mammals. Mammalian parents often provide extensive parental care which includes feeding, protecting, and teaching their offspring essential survival skills. For instance, meerkats take the time to train their pups in handling and eating scorpions, ensuring they can safely remove the stingers. This form of parental investment is significant in species with fewer offspring, such as humans, kangaroos, and pandas. These species' offspring are usually quite helpless at birth and require a lengthy period to develop skills and reach maturity, resulting in a prolonged juvenile stage.
Conversely, species with a Type III survivorship curve, like trees, marine invertebrates, and most fishes, produce a large number of offspring with minimal to no parental care. The high birth rates help to ensure that some offspring will survive to adulthood despite the high mortality rates in their early life stages. This strategy is markedly different from the intense parental care observed in mammals, where the focus is on the survival and development of relatively few young.