After 22 years of observations in Shark Bay, Australia, behavioral biologist Janet Mann and her colleagues have discovered that certain bottlenose dolphins, known as spongers, form social networks, showing the first hints of culture among nonhuman animals. Spongers are dolphins that wear marine basket sponges on their beaks as hunting tools, using them to root around on deep sandy bottoms and find fish concealed below the sand. Sponging is a complex hunting technique passed on from mother to offspring. A sponger must know where the sponges grow, how to pick the right sponge, how to remove the sponge intact from the ocean floor, and how and where to properly hunt.

Spongers typically live solitary lives, but over 22 years of observation, a pattern emerged. The 28 female spongers formed cliques with other female spongers that were not necessarily genetically related to them. This behavior differs from other animal behavior where circumstances, such as genetics or food sources, dictate the formation of groups. The fact that these spongers chose to associate based upon similar, socially learned behaviors makes their cliques a cultural first among animals.

Which of the following expresses the main idea of the passage?

(A) Sponging is a complex behavior used by some dolphins as a hunting technique.
(B) Any study of animal behavior must take place over an extended period of time in order for patterns to emerge.
(C) A small set of non-human animals has been found to form social networks.
(D) Studying how animals form groups is important to our understanding of nature.
(E) Only humans can form social networks.



Consider each of the answer choices separately and indicate all that apply.

Which of the following can be properly inferred from the passage?

A. Groups formed by genetic bonds or food supplies do not qualify as social networks.
B. All spongers of Shark Bay, Australia, form social networks.
C. Spongers can only be found in Shark Bay, Australia.