• Saguinus mystax;
  • Saguinus fuscicollis;
  • population recovery mechanisms;
  • mixed-species groups;
  • wildlife management


In 1978, 66% of the individuals of Saguinus mystax and 9.5% of Saguinus fuscicollis were cropped from a population at the Yarapa river, Peru. The effects of cropping on the remaining tamarin population were evaluated by conducting censuses in 1981 and 1982 and by trapping and release of Saguinus mystax in 1981. Three hundred kilometers of trail were covered in the censuses, and all the groups within the 1.9-km2 study area were located. Within three years after cropping, the population of S. mystax had increased by 124%, more than double the size left in 1978. Increased reproductive rate, early breeding, and reduced infant mortality contributed to the recovery. On the other hand, S. fuscicollis had decreased by 12% in the three years following the cropping but had increased in the fourth year to a level slightly below the precropping density. The cropping of more S. mystax than S. fuscicollis might have contributed to the decline of the latter. The cropping of a sizable percentage of S. mystax from a natural population does not seem to impair its recuperative powers. It may take longer than four years for a population exhibiting high density, such as that at the Yarapa site, to recover completely.