The Menstrual Cycle of the Primates.—Part VI. Further Observations on the Breeding of Primates, with special reference to the Suborders Lemuroidea and Tarsioidea



  • 1The Common Macaque (31. irus) experiences a conspicuous seasonal variation in fertility.
  • 2The Hamadryas baboon (P. hamadryas) breeds continuously, but also experiences a seasonal variation in its birth-rate. The period in which it reaches its maximum of fertility is different from that of the Common Macaque.
  • 3The Spectral Tarsier (Tarsius spectrum) breeds throughout the year, and apparently without any conspicuous seasonal variation.
  • 4Animals belonging to the genus Lemur give birth in London only very exceptionally outside the period March to June. All of 66 births were distributed in the period March to September, 64 falling between March and June, and 2 in September.
  • 5The Slow Loris (Nycticebus coucaizg) breeds continuously. Its curve of fertility seems to rise towards the end of the year.
  • 6The Tree Shrew (Tupaia sp.) has a breeding-season with a duration of at least eight months. Data are not available for the other four months of the year.