From 1931 to 1934, Carpenter conducted field research on the natural behavior of primates under the sponsorship of Yale University professor Robert M. Yerkes.
[2] This includes determining how to get an accurate count of individuals, recording and interpreting primate calls, and improving understanding of other complex social behaviors.
[2] According to Irven DeVore, "for the succeeding thirty years almost all of the accurate information available on the behavior of monkeys and apes living in natural environments was the result of Carpenter's research and writing."
[3] Though known for his innovations in field work, Carpenter also advocated for breeding rhesus macaques for scientific experimentation.
He initiated an effort to move 400 monkeys from India to Santiago Island, now part of Puerto Rico, for experimentation.