The investigation determined that a researcher had placed a single marmoset, like this one, in a ferret exercise ball to explore use of the ball by marmosets during research projects. However, investigators did not find evidence that animal was tormented while in the ball.Carmem A. Busko, Wikimedia CommonsThe inquiry, which was conducted by a subcommittee of the University's Institutional Animal Care and Use Committee (IACUC), included an examination of records and extensive interviews with research and veterinary staff.

The subcommittee's report has been approved and adopted by the full IACUC, which is chaired by a faculty member and whose members include a veterinarian, a practicing scientist, a nonscientist and a member of the local community who is not affiliated with the university.

The investigation determined that a researcher had placed a single marmoset in a ferret exercise ball to explore use of the ball by marmosets during research projects. The ball, which allows the animal to stand and move freely, rolls in response to the animal's movement. The ball was observed while on a track and on the floor, where it rolled slowly for a short distance. 

Those interviewed said that at no time did any person kick, push or roll the ball and the animal did not sustain any injury or show any signs of pain or distress. The marmoset was returned to its family unit immediately after the procedure, which took about 13 minutes.

While the investigation found that the marmoset had not been harmed or mistreated, it also found that use of the ball for this purpose had not been submitted for approval by the IACUC as required for all animal research procedures. The recommendations in the report include retraining of laboratory staff on adherence to all established practices and policies.

The report recommended that the laboratory, whose research activities were voluntarily suspended during the investigation, be reopened on a restricted schedule with regular monitoring.

The investigation did not find any evidence to support other claims made by the animal rights group. 

In recent years, the university has strengthened its program of animal care by hiring additional professional staff with expertise in laboratory animal medicine, creating a new Office of Research Integrity and Assurance to oversee regulatory compliance,  increasing training for IACUC members and investigators, and developing new guidelines, policies and procedures across several areas. 

Princeton’s program has been continuously accredited since 2002 by the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALACI), which evaluates organizations that use animals in research, teaching or testing. 

Since November 2011, the university has been found to meet all federal standards during annual unannounced inspections by the USDA's Animal and Plant Health Inspection Service.