This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. With the characterization of the chimpanzee genome, there has been an increased interest in this species as a research model for fields as diverse as AIDS and behavioral studies. This, along with continued Yerkes support of research for which the species is uniquely suitable, requires careful monitoring and management of animal assignments, which is now underway. Given that most of our chimpanzees are housed socially, considerable effort is invested in contraception to prevent pregnancies. IUDs are the primary method of choice, with females unsuitable for IUD insertion receiving hormonal interventions for contraception. Continued improvements to chimpanzee housing have included replacing wire mesh walls, improving doorway systems and providing additional environmental enrichment. These improvements facilitate animal welfare, animal husbandry, and chimpanzee research. Positive reinforcement training continues to be a high priority, including providing support to and working with Yerkes research personnel. The Center also has a dedicated cognitive testing facility. The overall project goal is to maintain and study a population of chimpanzees and to ensure availability of this species to appropriate NIH funded investigators.