Cognitive research in the United States spans approximately 100 years. Most studies have occurred in primate centers, fewer at universities, and for a brief period, in home-based projects focused on enculturation. Historically, great apes living in zoos have been under represented. A shift has occurred that affects the future of the field. Studies at primate centers have significantly decreased, all university based projects have ended, and work in zoos is increasing. The Simon Skjodt International Orangutan Center at the Indianapolis Zoo provides an example of one stable, longitudinally based project. The primary areas of study at the Center are symbolic representation, numerical competency, social learning, memory, and strategic reasoning. All data collection sessions are conducted with visitors present. Cognitive studies in a zoo environment promote great ape welfare, offer a platform for transformational public education, and provide an effective means to advance support for in situ conservation of great apes.

Estrildid finches (family: Estrildidae) are characterised by great intraspecific and intersexual variations in sexual traits, which include courtship song, dance and ornamental colourations of plumage. These features are expected to help us answer some questions about the evolution of sexual signals: (1) why multiple ornaments evolve in socially monogamous species; and (2) why, in certain species, males and females share identical sexual traits. To discuss these, first, I briefly review the past phylogenetic comparative studies of Estrildids and show that the three sexual traits evolved independently. Secondly, I focus on one behavioural component of the courtship dance, nesting material holding display, and test the idea that the display evolved as a signal of nest building ability using phylogenetic comparative approaches. The results showed that males exhibited nesting material holding displays in species where males tend to work harder to prepare nests, which indicates that parental cooperation plays a role in the evolution of sexual signals.