article_snippet.sent: Chimpanzees crossed in small subgroups.
article_snippet.sent: Whole parties crossed more rapidly when chimpanzees were more numerous in the crossing groups.'
article_snippet.sent: other members of the group also tended to form small groups of between two to three chimpanzees that crossed at a time.
highlights_snippet.sent: The chimps crossed in small groups, often running to get across quickly .
  