Although many chimpanzee populations live in environments containing oil palm nuts, members of only a few populations use stones to crack open the nuts. The most likely explanation for this behavioral difference between populations is that
a. Members of different populations differ in manual dexterity.
b. Members of different populations have different nutritional requirements.
c. Members of different populations differ in learning ability.
d. The use of stones to crack nuts has arisen and spread through social learning in only some populations.

Verified step by step guidance

1. Understand the context of the problem: The question is about behavioral differences in chimpanzee populations and why only some populations use stones to crack open oil palm nuts, despite living in similar environments.
2. Eliminate options that are less likely based on biological reasoning: For example, consider whether manual dexterity (option a) is likely to vary significantly between populations of the same species. Chimpanzees generally have similar physical capabilities, so this is unlikely to be the main reason.
3. Evaluate the role of nutritional requirements (option b): All chimpanzees have similar dietary needs, so differences in nutritional requirements are unlikely to explain why only some populations use stones to crack nuts.
4. Consider learning ability (option c): While learning ability can vary among individuals, it is unlikely to differ significantly between entire populations of the same species. This makes this option less plausible.
5. Focus on social learning (option d): Behavioral traits like tool use often spread through social learning, where individuals observe and imitate others. If only some populations exhibit this behavior, it is likely because the behavior originated in those populations and spread through social learning, rather than being an innate or physical difference.

Key Concepts

Social Learning

Social learning refers to the process by which individuals acquire new behaviors or knowledge by observing and imitating others. In the context of chimpanzees, this concept suggests that the use of tools, such as stones for cracking nuts, may be passed down through generations within certain populations, leading to variations in behavior based on cultural transmission.

Cultural Variation

Cultural variation in animal behavior highlights how different populations of the same species can develop distinct practices based on their social structures and environments. This concept is crucial for understanding why some chimpanzee groups utilize tools while others do not, as these behaviors can be influenced by the unique experiences and interactions within each group.

Manual Dexterity

Manual dexterity refers to the skillful use of the hands to manipulate objects. While it may play a role in the ability to use tools, the question suggests that differences in manual dexterity alone are unlikely to explain the observed behavioral differences among chimpanzee populations, as the presence of social learning and cultural factors are more significant in shaping these behaviors.