... to the primate husbandry of the German Primate Center (DPZ). My name is Uwe Schönmann. I am a biologist and the colony manager here at the DPZ. Let me invite you to guide you through our facilities. During this virtual tour you will gain direct insights into the daily work of our veterinarians and animal caretakers. You will receive useful and detailed information on the breeding of nonhuman primates for the purpose of research.
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Get to know the Colony Manager and his work.
Hello, my name is Uwe Schönmann and I am pleased that you join me on a tour through our primate facilities. I will give you information on primate housing and breeding as well as on our specific efforts in order to meet the particular demands of these highly sentient animals. As colony manager, I am responsible for the management of all primate groups kept in the German Primate Centre. The most important aspect of my daily work is to control the health status and general welfare of our animals together with our animal caretakers and veterinarians. We also discuss regularly with our scientists about which primate species they need for their research and how we can provide the best housing and care for the animals. To do so, we follow the principles of the three R’s, which are continuously developed since more than 50 years and are embedded in national and international legislation regulating the use of animals in scientific procedures. The three R’s stand for:
- Methods, which avoid or replace the use of animals in research.
- Methods, which minimize the number of animals used per experiment.
- Methods, which reduce suffering and improve animal welfare.
While most animals remain here at the DPZ, we also make primates and biological samples of primates available for other publicly funded research institutes.
What is a primate and what is a nonhuman primate?
A “primate” is mammal of the order primates. Lemurs, lorises, tarsiers, monkeys, apes, as well as humans are all primates. The term nonhuman primate refers to all primates excluding us humans.
How many individuals and species are kept?
Currently, the DPZ keeps approximately 1300 nonhuman primates, belonging to seven different species. However, more than 75 per cent of the nonhuman primates at the DPZ are either rhesus macaques (Macaca mulatta) or common marmosets (Callithrix jacchus). This is completed by smaller breeding colonies of hamadryas baboons (Papio hamadryas), longtailed macaques (Macaca fascicularis), black and white ruffed lemurs (Varecia variegata), ring-tailed lemurs (Lemur catta) and mouse lemurs (Microcebus murinus). Great apes such as gorillas, orang utans, chimpanzees or gibbons are not kept in the DPZ, because biomedical research with these species is strictly prohibited in the European Union.
Why are primates kept at the DPZ?
Primates are bred and kept at the DPZ. About one third of the animals are for research purposes at the DPZ or given to other scientific institutions. Two-thirds of the animals live in family groups in breeding groups. Nonhuman primates are highly developed mammals and closely related to humans. Therefore, they serve as ideal model organisms to investigate human diseases or complex neuronal processes. Moreover, their flexibility in social behaviors and adaptability to a large variety of different ecosystems make primates best suited for ecological, behavioral and evolutionary research. The primate husbandry also serves as a service unit providing other institutions access to high quality samples for animal model research, for example through the biobank.
What is the biobank?
Research with primates sometimes necessitates euthanizing animals. Tissue samples and genetic material (DNA, cDNA, RNA) obtained from these animals represent a valuable resource for scientists because primate material is rare. Especially for material requested for biomedical studies high quality is needed including the knowledge about the genetic background and health history of the animal. If the tissue and/or genetic material are archived, i.e. stored in freezers with exact documentation of the sample details, this is called biobanking. Since the number of animals needed for research can be reduced by efficient resource sharing, biobanking contributes to the 3Rs-concept of reduction, refinement and replacement.
Why do we have to change our shoes?
Before entering the area of enclosures, everybody e.g. animal caretakers, veterinarians and veterinary inspection officers have to change their shoes. This prevents bacteria, viruses and germs from outside entering the enclosure facility. This is especially important for the work with nonhuman primates as they can be easily infected with infectious diseases of humans, such as chickenpox or tuberculosis.
Why do we have to change clothes?
Hygiene and health of our animals are our highest precepts. Therefore, the facility offers the most current standards to prevent animals from getting an infection or disease. Everybody who enters the enclosure facility has to change clothing. To do so, the enclosure facility offers a special changing room, which physically separates outdoors from the enclosure area. Everybody who enters the enclosure area has to follow these rules of changing the clothes in order to prevent bacteria, viruses and germs from outside entering the enclosure facility.
Why are there washing machines and shower in the changing room?
The changing rooms are equipped with a shower as well as with washing machines. If animal caretakers work with different species during the same day, they have to shower in between to exclude the possibility of transferring infectious material from one species to another. The presence of the washing machines allows cleaning the work clothes within the decontaminated environment and therefore additionally prevents the intrusion of infectious material, because work clothes never leave the decontaminated area.
Technical instruments and heating
How is technology improving animal health and welfare?
Different primate species require different climatic conditions. Using modern technology we can control the ventilation, humidity and temperature within the enclosure area. This tremendously increases our ability to provide our animals with optimal housing conditions. For the nocturnal mouse lemurs for example, we are able to control the day and night rhythm in order to study their natural behavior during the day. In case of a system failure our alarm system will take over and immediately signal problems within the facility.
What is the litter good for?
The function of the litter (e.g. woodchips) is to absorb urine and feces of the animals and to keep the animals’ environment dry. During everyday cleaning, the animal caretakers remove used litter with urine and feces and replace it with new litter. During this process the caretakers also regularly take fecal samples, which are later used to monitor the hormonal status and the health of the animals. Furthermore, the litter is used by the animals for play and foraging and enriches their environment.
What are the tasks of the animal caretakers?
Care of nonhuman primates used in scientific research needs a considerable amount of engagement and responsibility. Animal caretakers need to have a strong understanding and knowledge of primate behavior, anatomy and physiology in order ensure optimal conditions for the animals and thus, for scientific research. The work of animal caretaker is highly variable. Besides cleaning of the enclosures and feeding they are also responsible for the creation of the environment and training of the animals. Furthermore, the caretakers check health and behavior of each animal every day. It is really important to carefully document everything and report signs of illness or abnormal behavior. Compared to zoological parks, direct contact between animals and caretakers is normally limited in order to avoid habituation to humans.
How often is the cage cleaned?
Cages are cleaned everyday by the animal caretakers. For every group of the colony separate cleaning equipment is used to reduce the probability of transferring infectious material from one group to the other. The enclosures are completely washed with a pressure cleaner at least once a month, depending on the level of dirt produced by the animals.
Lever of outdoor flap
What is the lever good for?
Normally, the animals can roam freely in their combined indoor and outdoor enclosures. The lever is controlling the outdoor flap by opening or closing the passage from outdoor to indoor. This is useful to temporarily shut out the animals, in case the animal caretaker has to do work within the enclosure such as cleaning or installing a new climbing frame.
What is environmental enrichment?
Nonhuman primates have a large brain and highly developed cognitive abilities. Therefore, it is important to provide them with a stimulating environment. That is what we call enrichment. It improves the welfare of the animals in captivity and is important for their physical and psychological health. Enrichment is important for all animals kept in a non-natural environment, however this applies especially to primates.
The principal of enrichment is to increase the complexity of the artificial environment of the animals in order encourage natural behavior.
Why is environmental enrichment necessary?
Introducing complexity is very important, because it maintains an active social life, changes physical environment, provides a variety of food items in challenging ways and stimulates the minds and senses of the animals. Introducing complexity can already consist of changing some branches in the cage from time to time or introducing a new object to explore or to climb on. Animal caretakers often provide food items that are hidden or have to be manipulated before they can be eaten.
Environmental enrichment vs. health and safety
If a novelty is introduced the animals and their interactions are observed by the animal caretakers. It is important that the newly introduced object is safe for the animals. However, a too complex environment and the introduction of novelties can be counterproductive. The animals should always have the choice to interact or not with parts of their environment.
Importance of daylight and night and day rhythm.
Although animals in the breeding groups can roam freely between indoor and outdoor enclosure, enclosures are equipped with large windows to ensure natural light entering the indoor enclosure. This is essential for the health of our animals and ensures they can keep their natural rhythm, which is triggered by natural light.
Wall of enclosure
Guidelines for the use and breeding of animals for the purpose of research
Keeping animals requires careful evaluation and planning of the facilities they are kept in. Germany as well as the European Union has strict regulations concerning the use and breeding of animals for research purposes. The structures, such as the wall of the enclosure, have to be safe for the animals, but also to be cleaned easily. Moreover, the minimum size of an enclosure is formalized in international legislation. For the rhesus macaques of four years of age this for example 3,6 m3 per animal and minimal height of the enclosure of 1,8m (EU-Directive 2010/63). We comply these spatial requirements in any case and even exceed them in most cases.
What is a rhesus macaques?
Rhesus macaques or rhesus monkeys are native to nothern India, Bangladesh, Pakistan, Nepal, Burma, Thailand, Afghanistan, Vietnam, southern China, and some neighboring ares. They have the widest geographic range of any nonhuman primate. They are adapted to a variety of habitats. The rhesus macaque (Macaca mulatta) is one of the best-known and studied species of nonhuman primates. Their close relatedness to humans make them ideal candidates for biomedical research on human-health related topics. The rhesus factor on the surface of our blood cells (erythrocytes) is probably the most famous medical discovery attributed to experimental research with rhesus macaques. Of all nonhuman primates, the rhesus macaque is the most frequently used species for scientific research today. This includes studies of infectious human diseases such as HIV and Ebola but also neurobiological, genetic and behavioral studies.
Science at the DPZ with rhesus macaques
Scientific research involving rhesus macaques is conducted in the sections of neuroscience and infection research at the DPZ. Whereas the section of infection research aims at improving our understanding of various human diseases such as HIV, Ebola or Hepatitis, the section of neuroscience is exploring the biological processes happening in our brain when we plan and fulfill a movement with our body or parts of our body, such as our hands. More information on this topic can be found in the video below.
Grooming and breeding of primate groups
What is grooming?
Grooming is a natural body care behavior of primates. Besides reducing the amount of parasites on the body it is very important in order to maintain and establish social relationships within primate groups.
How can knowledge about the animal’s social structure and behavior in nature improve the animal welfare and breeding in captivity?
Rhesus macaques are normally living in harem groups in the wild consisting of an alpha male, several females and their offspring. As male offspring grow older, they normally want to take over the dominant role of the alpha male. This can result in fights over the females of the group. If they cannot overtake the alpha role they leave their group to find their own harem somewhere else. This happens around the age of three years. Using this knowledge, only young males at the age of three are taken from the group and kept in smaller groups for the use in scientific research. This is the time where they would normally leave the group and form smaller groups with other young males. From time to time the alpha male has to be changed, too. This is also happening in the wild and prevents the group from inbreeding. Old females are normally left in the groups even if they do not reproduce anymore, because they are maintaining harmony in the group. In general, the breeding management needs a lot of experience and careful birth control as we do not want to breed more animals than needed.
Primates are usually moving not only on the ground, but in a three dimensional space. Outdoor enclosures are therefore constructed as cages with meshed fences instead of glass. This substantially increases the environment for the animals as they can use the mesh to climb.
How does the environment influence animal behavior?
The captive environment should allow and encourage natural behavior as shown by the species in the wild. This can be behaviors and postures like leaping, climbing, hanging upside-down, and running as well as clinging or jumping. The artificial environment should also allow all social behaviors like grooming, playing, huddling or the display of dominance, which is very important to all primate societies.
What do the animals eat?
Primates eat a large variety of different food items in their natural environment. Different species have different diets and are sometimes specialized to a certain diet such as fruits, leaves or gum of trees. Moreover, depending on their diet the animals have to manipulate and work for food in order get the appropriate amount of nutrients. In order to provide our animals with all necessary nutrients and to offer them different tasks to encourage natural behavior, we feed a large variety of food items. Pellets are fed in order to ensure that all animals have access to all nutrients they need. Additionally, we feed all kinds of vegetables and fruits as well as yoghurt or oat flakes. A well-balanced combination of proteins, carbohydrates, minerals and vitamins is essential for healthy animals.
Hygiene during food preparation
During food preparation the animal caretaker has to wear gloves to ensure high hygienic standard, which is top priority in the primate husbandry.
Extra food and environmental enrichment
In their natural environment primates have to search for food, manipulate trees, fruits or the bark of a tree. In order to get the appropriate amount of nutrition they often need to work hard. This should be imitated as best as possible and the animal caretaker comes up with new tasks for the primates to explore. Knowledge of the kind of food the animals like best can also improve cooperation of animals for medical treatments or training for research purposes.
A good example for this is gum of trees, which makes a great proportion of our marmoset’s natural diet in the rainforests of Brazil. In captivity this can be replaced by gum Arabic or acacia gum. Providing gum artificially inside or on hanging structures encourages the animals to work for their food, as they would do in the wild.
What are the tasks of the veterinarians?
The primate husbandry has two veterinarians to ensure best medical care for our animals all year round. Additional veterinarians are working within the research departments of the DPZ. If an animal is injured or shows abnormal behavior it can be examined and treated instantaneously 365 days a year. All animals of the breeding groups receive a general examination once a year, where they are checked for diseases such as tuberculosis, parasites such as worms and vaccination status. Animals used in scientific research are examined everyday by our veterinarians.
Once a month the office for consumer protection, animal welfare and veterinary practice is sending an officer to the primate husbandry for an unannounced inspection in order to examine and check the health and welfare of the animals and the compliance with the guidelines for keeping and breeding primates for research purposes.
How can we tell our animals apart?
Besides having normal names all animals are equipped with a microchip for identification. The microchip that is also used in pet dogs, has eight digits and allows identifying each individual electronically. The chip can be read with a microchip reader.
What is a marmoset?
Common marmosets (Callithrix jacchus) are a type of monkey of the genus Callithrix originating and distributed in northeastern Brazil. They have very distinctive white ear tufts, a striped tail and grey, blackish or brownish coat. In the wild they live in small family groups of up to 15 individuals. They show a large repertoire of social behaviors as well as a broad spectrum in their diet, e.g. gum, insects, lizards, fruits and nectar.
Science with marmosets at the DPZ
Scientific research involving common marmosets is conducted in the areas of stem cell biology, infection diseases and auditory neuroscience. Prof. Dr. Tobias Moser and the Institute for Auditory Neuroscience in conjunction with the Auditory Neuroscience group at the DPZ are doing ground work to improve the quality of hearing for patients with cochlear implants.
What is a cochlear implant?
The cochlear implant is probably the most successful neuroprosthesis developed so far. Up to 450.000 hearing-impaired people are profiting today from cochlear implants and are able to develop open speech comprehension. The cochlear implant replaces the function of hair cell receptors and directly stimulates the auditory nerve in the cochlea using electric impulses. How that works illustrates the following video:
Improving the quality of hearing using optical stimulation in future cochlear implants
Electric stimulation of the auditory nerve in current implants is limited in terms of further improving the quality of hearing. Using light instead of electric stimulation could improve the spatial and temporal resolution of the stimuli that reach the auditory nerve. Using this technique the researchers could already successfully stimulate the auditory nerve of mice. Making this technique available for humans in the future requires tests with close human relatives. What the scientists hope to achieve, why marmosets are particularly suited as animal model for this purpose and how the animals are motivated to participate explains the interview with scientist Josey Mintel from the Auditory Neuroscience group.
Thank you very much…
…for your interest in the primate husbandry of the DPZ. I hope you enjoyed the tour. If you have further questions, please do not hesitate to contact us. You are also very welcome to visit us and join a guided tour through the DPZ. More information regarding our animals, animal welfare and research on primates can be obtained on our webpage and the following external sites.