Ovulation in female tamarins typically occurs between 12 and 17 months of age, whereas in male tamarins, sperm production occurs slightly later at about 13 to 18 months.[1] The birth of infants has been observed in both early January and mid July.[2] Black-handed tamarins (like all other Callitrichids) usually produce fraternal twins, but litters may consist of 2-4 infants.