1910. Maternal instinct in a monkey. _Journal of Animal Behavior_, vol. 5, 403-405. 1916. Provision for the study of the monkeys and apes. _Science_, vol. 43, 231-234. YERKES, R.M. and COBURN, C.A. A study of the behavior of the pig 1915. _Sus scrofa_ by the multiple-choice method. _Journal of_ _Animal Behavior_, vol. 5, 185-225. End of the Project Gutenberg EBook of The Mental Life of Monkeys and Apes by Robert M. Yerkes