The CNPRC houses over 4,000 monkeys for research and breeding. Research at the Center spans the entire life history of these primates, ranging from gametes through fetal biology and neonatology, to the juvenile, adult and geriatric stages of life. We take the stewardship, welfare and care of the animals seriously, and the extensive teams of veterinarians, clinical and service laboratories, animal care, pathology, enrichment and behavior management staff work together to provide outstanding care to all of the animals.

Rhesus Macaques

The majority of the CNPRC animals are rhesus monkeys (Macaca mulatta), which are the nonhuman primates most frequently used in research. Most of these animals live in large half-acre outdoor field corrals, in natural social groups similar to those in the wild consisting of 80-120 animals, and smaller groups of around 15 animals in housing called “corncribs”. The remainder of animals are housed as pairs in indoor housing, with a small percent housed singly as needed. In the wild, a rhesus macaque’s life span is up to about 18 years of age. At the CNPRC, with excellent nutrition and medical care, these animals can live up to 38 years of age. The aged rhesus colony at the Center is unique amongst the primate centers, and provides distinctive opportunities to understand normal aging and to develop treatments and solutions for age-related health problems.

Titi Monkeys

The CNPRC has a population of approximately 100 South American titi monkeys (Callicebus cupreus). These monkeys are small, tree-dwelling primates from South America, and live in monogamous family groups that consist of the parents and their offspring. The father is the main caretaker for the infants, bringing the infant to its mother only for nursing until the infant is weaned at around 5 months of age. Titi monkeys are used in noninvasive biobehavioral studies of attachment and parental behavior, as well as in studies of autism treatments and understanding normal brain and behavioral development. Titi monkeys allow us to understand social bonds, particularly in adult males, which form attachment bonds unlike most other mammalian species.

The outdoor corrals serve as valuable opportunities for the investigation of social behavior in a natural environment, as well as studying the stages of development. These corrals vary in the length of time they have been formed, ranging from 1 to over 20 years. The smaller, corncrib housing provides an excellent opportunity for behavioral research and vaccine studies, where blood samples are collected monthly and the animals can remain in a social outdoor setting.

The large field corrals house naturalistic demographics of infants to geriatric animals in their extended family groups. Healthy geriatric animals remain in these outdoor corrals with family members in the rich social environment of their home community. In addition to day-to-day health care for all animals, geriatric animals receive semi-annual geriatric veterinary workups and evaluations.

In addition to their healthy diet of twice-daily feedings of specially formulated monkey chow, animals are also provided with fresh fruits and vegetables twice per week. Rhesus macaques spend most of their day foraging for insects, grass, seeds and other treats that the CNPRC Enrichment staff have provided for them.

Titi monkeys at the CNPRC are housed in their natural family groups, which consist of an adult male and female and their offspring. The whole family engages in tail-twining, in which they wrap their tails together. At the CNPRC they sleep upright on branches with their tails twined, as they would in the wild. Offspring can live with their parents until well past sexual maturity, and do not reproduce while in their natal group. Titi monkey enrichment includes natural wood in their enclosures, foraging opportunities including mealworms (yum!), and coconuts which are favorite toys to groom as they have natural “hair.”

Understanding social bonds, particularly in adult titi males, also contributes to titi monkey health; for instance, CNPRC scientists have studied how their formation of social bonds can reduce stress and lower glucose levels in pair-bonded titi monkeys.

Titi monkeys receive a varied diet that includes monkey chow, apples, bananas, carrots, and rice cereal. Food enrichment includes spinach, mealworms, puffed rice and oats; and vitamin supplements are given once a week. When titi monkeys are trained to participate in research (for instance, to give urine samples), they are rewarded with small peanuts as a special treat.

Specific Pathogen Free Primates

Since 1987, the CNPRC has been establishing specific pathogen free (SPF) monkey colonies with additional support by the National Institutes of Health. The goal of this breeding program is to improve both the overall nonhuman primate colony health and improve the quality of science conducted through eliminating persistent viral infections representing potential confounding variables. The CNPRC SPF colony also increases personnel safety for animal care staff by reducing health risks associated with potential exposure to nonhuman primate pathogens.

National Institute on Aging, CNPRC Aged Monkey Colony

The National Institute on Aging (NIA), a division of the National Institutes of Health, supports research on aging rhesus monkeys at multiple National Primate Research Centers including the CNPRC. The CNPRC NIA Colony of geriatric rhesus macaques (≥19 years) is managed and supported for use by investigators in aging research. The NIA Colony and all geriatric monkeys at the CNPRC participate in semi-annual assessments by the veterinary staff (e.g., physical examination, clinical pathology) to ensure overall health and to monitor for potential age-related complications. The Colony Management and Research Services staff also track eligible animals in the CNPRC breeding corrals for potential recruitment to the NIA Colony at 19 years of age.

This program aims to:

  • Support and maintain NIA rhesus monkeys for investigators nationwide that are conducting aging-related research. The goal is to proactively manage the NIA Colony in order to maximize the number of healthy geriatric rhesus monkeys for aging research. The Primate Services staff work closely together with investigators to support translational rhesus monkey models of human aging.
  • Provide expertise and services at the highest quality level for investigators at the local, regional, and national levels. Through established protocols, guidelines, and expertise ensure investigators are provided sufficient healthy, well-characterized aged animals and correlative services and infrastructure to support aging and lifespan health research objectives.
geriatric rhesus monkey

Geriatric rhesus macaque at the CNPRC