The social organization of howling monkeys was studied by:

Explanation

The social organization of howling monkeys has been studied by several researchers. Among the options you provided, Allen, Thorpe, Schjelderup-Ebbe, and Carpenter, only one of them is directly associated with studying howling monkeys' social organization. The correct answer is Carpenter. Allen: It is unclear which specific Allen you are referring to, as there have been many researchers named Allen in various fields. Without further information, it is difficult to determine if any of them have specifically studied howling monkeys' social organization. Thorpe: Again, without more context, it is challenging to identify which Thorpe you are referring to. There have been multiple researchers with the last name Thorpe. However, it is worth mentioning that the name Thorpe is not commonly associated with studies on howling monkeys' social organization. Schjelderup-Ebbe: Konrad Lorenz is well-known for his work on ethology and animal behavior, including his studies on the pecking order in chickens, which introduced the concept of "dominance hierarchy" and "pecking order." However, Schjelderup-Ebbe is not typically associated with howling monkeys' social organization research. It's possible there may be some connection or reference I am not aware of, but it is not a commonly recognized association. Carpenter: Robert Carpenter is a primatologist known for his extensive research on howling monkeys' social organization. His work has focused on studying the behavior, ecology, and social dynamics of howling monkeys in their natural habitats. Carpenter's research has contributed significantly to our understanding of howling monkey social systems, including their vocalizations, group composition, and mating strategies. In conclusion, among the options provided, Carpenter is the researcher most closely associated with studying the social organization of howling monkeys.