7. Working With Animals

Animals in laboratories are often scared of people—for good reason!—which makes it difficult to work with them without distressing them at the same time. What do you do to make the animals feel relatively at ease when you work with them?

7,1. Training Monkeys and Dealing with Monkeys—Practical Tips

I am working with several investigators who claim that in order to get macaques to "listen," they first have to "teach" them to be submissive—for example, by intimidating them through shouting. Only then, they claim, would the animals be ready to learn certain tasks during experiments. The idea sounds quite barbaric to me. Is it really ever appropriate to punish an animal?

I have trained many rhesus and stump-tailed macaques to cooperate during various procedures and applied with strict consistency positive reinforcement. You as trainer or handler need to be dominant, not to get the animal to comply, but for your own safety. If the animal doesn't respect you, you are at a risk to be scratched or bitten whenever you interact with the subject. How do you get dominant? Not with a stick, not with shouting, not with impatient reactions, and not with any kind of punishment, but instead with gentle firmness. It's a subtle process that I cannot translate into words, but it allows the animal to trust you. That trust is your safeguard against aggression and, I believe, gives the animal more space to comprehend the training tasks.

In my experience, it doesn't help to shout at anyone, including a monkey, when you want to get somebody to do something. Shouting is a punishment, and punishment blocks behavior. In contrast to this, positive reinforcement increases the likelihood that the subject will understand what you want and, therefore, show the expected behavior. It is never appropriate to use a punisher to get an animal to do something. It is also never appropriate to punish an animal in order to eliminate a certain behavior, such as urinating at you.

I very much agree with you: Any kind of intimidation—be it shouting, showing a broomstick or even the net—is bound to have the opposite effect. The animal will feel scared and his or her trust in you will diminish or go down the drain altogether. An intimidated fearful animal, whom you have quasi-forced into submission, will not listen to you because he or she no longer feels confident enough in your presence to do what you expect him or her to do. Your negative energy essentially blocks the animal's capacity to learn. It's a losing battle that will make you—and the animal—very frustrated (Figure 54).

Figure 54 An animal made to feel submissive and fearful will not comprehend what you want him or her to do, but rather will try to get away from you. Photo by Viktor Reinhardt.

What do you do if an animal is very aggressive and you need to protect yourself and attending staff?

We have a male rhesus who often exhibits aggressive behavior to the animal care staff. He tries to grab and scratch them whenever they get close enough. The only way I can place puzzle feeders on his cage or do anything near him is to hold a brush in my hand. The sight of the brush has proven to be "an equalizer." He doesn't try to scratch or grab me as long as that brush is in my hand.

This "equalization" technique sounds fair to me, but the question remains open: Does it "cure" the animal from his misgivings against humans? I very much doubt it. I guess it would help to find out the original reason that made this male so suspicious, presumably non-trusting, and aggressive against humans in general. After all, not all male rhesus are so aggressive. This particular gentleman probably had very bad experience(s) with people that made him so aggressive. I would argue, that:

I completely agree that your rhesus male's exhibition of aggression is a human problem and not a monkey problem. How we handle and treat the animals has a lot to do with how they will eventually treat us. The unfortunate thing is that you're dealing with someone else's problem now. We had a similar situation at our facility; this is how we addressed it:

  1. We have a 15-kg rhesus male whose mission in life is to scratch anyone or anything that comes near his cage. This one monkey alone used to account for half of all scratch incidents that occurred at our facility. I think he likes the reaction he can trigger in the attending personnel more than anything else, but I must admit it is a challenge not to react when a monkey has just ripped your glove and scratched your hand. This can be quite scary when you consider the possible consequences to yourself! It was finally decided that something had to be done about this monkey, and I suggested training him.
  2. This monkey loves treats, so it wasn't hard motivating him. Since he could be so dangerous, we had to be very careful working with him. Our cages have small square holes near the bottom. These were the only places we could deliver the treats without being in his reach. We first trained him to sit, which actually came very naturally due to the place we were rewarding him. We gave him a treat only when he was actually sitting down 1) in the front corner of the cage and then 2) would take the treats quietly.
  3. The caretaker assigned to do the training worked with this male one or two times every day. By the end of the first month, the monkey was taking treats from the caretaker's hand through the bars without making a fuss.
  4. By now, he has stopped his aggressive overtures almost completely. The only time we still have problems with him is, when the room is being washed down and when a strange person is in the room.

Gentle firmness and positive reinforcement are much better training tools than punishment of "undesired" reactions and behaviors.

7,2. Injection and Blood Collection—How to Minimize Stress Reactions

Injection—especially for sedation—and blood collection are very common procedures in biomedical research laboratories. It is my experience with macaques and rabbits that the animals often show avoidance and fear reactions to this procedure, suggesting that their "normal" physiological status is altered even before the actual test or experiment is performed. Are there practical solutions to this problem?

7,2,1. Primates

I have successfully trained two of my singly housed adult rhesus males to cooperate during intramuscular injection. As a first step, they learned to present their thighs to the front of the cage and then to be touched with the target, consisting of a small plastic rod. Next, I started gently poking the thigh with the target, then switched to a syringe without needle, followed by a syringe capped with a large blunt needle and then with a normal 25 gauge needle, which I finally inserted into the muscle. I praised the animals at the successful completion of each training session. Both males have learned to cooperate and neither of them reacts in any negative manner to this procedure (Figure 55). I should perhaps emphasize that the two get their injections in their home cages without being squeezed. They are in control of the situation, but they do cooperate very well. There is no doubt in my mind that the injection procedure is not a stressful event for them.

Figure 55  Rhesus macaques can readily be trained to cooperate during intramuscular injection without being restrained. Photo by Viktor Reinhardt

I have always found that adult male rhesus react quite well to frequent (once a week) injections if I tell them what I am doing. I show them the needle and I tell them, "I need to give you a small shot." I always talk in a calm soothing voice when I am working with them, and it is not uncommon that they spontaneously present for me, so that I can easily do the procedure (Figure 56). Since the animals show no signs of fear and resistance, injection is unlikely to be a stressful experience for them. After the injection, the animal is praised with "good boy!" or similar phrases such as "you are such a good monkey!" I believe the animals deserve to be approached and handled with respect and trust. They definitely respond better to people they know and trust. Typically, they respond with fear and/or aggression to investigators and to the veterinarian. This implies that I am usually requested to first sedate the animals before the investigator or veterinarian handles them.

Figure 56  With some patience, it is easy to train rhesus macaques to allow subcutaneous injection without being restrained. Photo by Viktor Reinhardt

With positive reinforcement, I have trained adult female cynos to cooperate during intramuscular injection in home cages that are not equipped with squeeze-backs. When they can trust you, they readily learn to cooperate during this common procedure. These animals work with rather than against me, which automatically implies that they show no fear or stress reactions during the procedure.

I intend to train rhesus and cynos to present for blood collection. So far, I have gained the trust of several animals, but I don't know how far I can trust them in return? I respect them very much—more than I respect some human primates—but the animals are under stress and, therefore, may turn on me for no apparent reason.

It's true, if the animals are under stress while you are working with them, there is a great risk that they will show aggressive reactions to you, in an attempt to get away from the stressful situation. One of the conditions of successful and safe positive reinforcement training is a stress-free work environment, both for the animal and for you. This means, neither the animal nor you should be under the emotional influence of fear, apprehension or frustration. These emotions are dangerous when your handle monkeys or, for that matter, any other animals.

You should reach a stage when you know that you can trust the trainee while you work with him or her. This does not mean that you should not be alert, but any traces of mistrust and fear puts you into a seriously dangerous position. Do not work with an animal, unless you have trust in him or her! For your additional safety, you will always have to make sure that your interaction with the trainee will not be disturbed or disrupted by any unexpected event, such as personnel entering the room or loud personnel passing in hallways.

How long does it take to train a macaque to present a leg for a blood draw a) when you make use of the squeeze-back, and b) when the cage has no squeeze-back and the animal is free to come or stay away from you?

My experience might have gone a little differently if the monkeys I worked with had trusted humans, but I had to spend almost an entire month just gaining their trust so that I could touch them. Rather than using a squeeze-back, I used a target to train my animals to come freely to the front of the cage.


Figure 57 Macaques—here a male rhesus macaque—who have been trained, often cooperate during blood collection in the home cage without the need of a squeeze-back. Photo by Viktor Reinhardt.

To achieve active cooperation in the home cage, I invested on the average 40 minutes with adult male rhesus macaques (Reinhardt, 1991), and 34 minutes with adult female stump-tailed macaques (Reinhardt and Cowley, 1992). These animals lived in squeeze-back equipped cages. They were used to being squeezed for routine procedures, and I also made use of the squeeze-backs during the initial steps of the training. Once trained, the animals showed no behavioral signs of stress or distress prior to and during blood collection, and with many of them, it was not necessary to use the squeeze-back at all (Figure 57). They also failed to show a significant cortisol response to this common procedure (Reinhardt et al., 1991; Reinhardt and Cowley, 1992). I have worked with adult and juvenile rhesus monkeys and noticed that the juveniles—unlike the adults—have difficulties to overcome their fear of being handled. Yes, you can also train them to cooperate during blood collection (Figure 58a,b), but the time investment is considerably higher than with adults (Reinhardt, 1992c).



Figure 58a,b  Young rhesus macaques can be trained to cooperate during blood collection, but it takes them a relatively long time to overcome their initial fear of being touched by a human. Photos by Viktor Reinhardt.

If you want to employ only positive reinforcement rather than using also the squeeze-back as feels appropriate, you will have to give yourself lots of time to train. Your timetable will not match up to theirs! If training these animals is going to be your main job for the next couple of months, giving yourself four months of training time will probably be sufficient.

I have worked with both single-housed and pair-housed rhesus and got the impression that the pair-housed animals learn faster, perhaps because of the reassurance by the companion.

When you have successfully trained monkeys, how do they react to other handlers?

It is my experience with blood collection and topical drug application training that, once trained, the subjects will cooperate also with other personnel, even strangers whom they have never seen, under the condition that the other person knows what he or she is doing and approaches the animal with gentle firmness.

7,2,2. Other Species

I have checked the literature, and I have not found a single publication reporting that any species other than primates have been trained to cooperate during injection or blood collection.

Rodents are the toughest animals for me to give injections without stressing them unduly. There seems to be no way of rewarding them except for their release—so it seems impossible to develop a positive reinforcement training technique for them.

When giving cows injections, I get my best results when speaking softly and taking all the time needed not to rush through the procedure, so that they have a chance to settle down, see where I am and what I am doing. And before I inject, I tell them reassuringly that I am not doing anything that is dangerous for them. It sounds very anthropomorphic, but I do believe that animals pick up on our emotions and intentions and respond accordingly when we are calm versus nervous, kind versus callous, patient versus impatient, and confident versus afraid.

7,2,3. Conclusions

While it is relatively easy to train monkeys to cooperate during injection and blood collection, there is no published evidence that cooperation can also be obtained from rodents, rabbits, dogs and cats.

7,3. Oral Drug Administration—How to Minimize Stress Reactions

Oral drug administration procedures are often stressful and involve considerable risks for the subject, whether he or she is a rat, mouse, monkey, dog or any other species. Does anyone have experience with refinement techniques?

7,3,1. Rabbits

Gavage works well with rabbits. I do not use a gag, but instead hold the rabbit's mouth closed while gently pushing a pediatric feeding tube—with the appropriate length pre-marked—through the diastema. It is easiest to restrain the rabbit in a natural upright position with the neck slightly extended. The animals tolerate this procedure well, even over repeated dosing.

One of our protocols requires that rabbits be given oral aspirin once daily for 30 days. We mix the aspirin with corn oil and flavor this suspension with orange. Believe it or not, the rabbits love it! This kind of oral drug administration is not at all stressful.

Marr et al. (1993) offered rabbits a daily sucrose solution from a tuberculin syringe with a sucrose-granule-coated tip. After five days, the sucrose solution was exchanged with tosufloxacin, but the tip of the syringe remained coated with sucrose granules. Within two days, eight of the ten rabbits willingly took the antibiotic, the remainder requiring minimal encouragement. This procedure was time-efficient, painless and never required more than one technician. It also eliminated physical manipulation, unnecessary stress, and the danger of injury to the animal from improper gastric intubation.

7,3,2. Rats, Mice and Hamsters

I have gavaged rats and hamsters daily for more than six months without noticeably stressing the animals. The success of this dosing method largely depends on your skills and compassion for the animals. I have made it a routine to always offer the animals a little food reward after the gavage. By doing this, the animals will come to the front of the cage, let you restrain them without struggling, hence you can hold them with gentle firmness rather than with a tight grip. Mice seem to be more suspicious. They do not really relax, even when you hold them as carefully as possible, and they usually refuse even the most tasty food reward.

What you describe seems great if not perfect for rats and hamsters. Why do you think mice are more difficult to win over?

I would say that it is a species-specific response to humans. Mice in research will learn to get a treat and come to the front of the cage to receive it, but it is my experience that they never bond with the technician and do not like to be touched. Rats and hamsters give the impression that they like it when you hold them in your hand—even for gavage.

We recently completed a 90-day study of two drugs—indomethacin and celecoxib—mixed in chocolate. Rats like chocolate and this solved a major headache of oral gavage. The rats, living in trios, were first allowed to develop a taste for pure chocolate, by placing a chocolate pellet into their mouth using a 14-gauge gavage needle. After eight days of training, 95 percent of 57 rats displayed eager anticipation of the decoy whenever the cage door was opened. The rats' response did not change when the chocolate pellets contained the test drugs, and they swallowed them without hesitation (Huang-Brown and Guhad, 2002), which means that the oral dosing was not a stressful event for them.

Rats also like sucrose. It took Rourke and Pemberton (2007) only three days to successfully train 12 male rats to voluntarily drink from 1 ml syringes containing a solution of 1 mg donepezil (an approved medicine for treatment of Alzerheimer's Disease) suspended in a 5-10% sucrose solution (Figure 59a,b).

Figure 59a,b  Rats readily learn to drink a 5-10% sucrose-drug solution from a syringe. Photo credit: Claire Rourke (reproduced with permission of the Institute of Animal Technology; published in Animal Technology and Welfare 6, 15-17, 2007)

7,3,3. Primates

Our vervet monkeys voluntarily swallow drugs when we mix these with their regular diet, consisting of pre-cooked maize, fortified with vitamins, minerals and other ingredients. The dry ingredients are blended with water and form a stiff putty-like paste, which is an ideal vehicle for mixing in test substances. If the flavor needs to be masked, there are a variety of possibilities, such as honey and syrup, depending on what the protocol permits. We usually administer the compound in about a third of the morning feed. The bulk of the food is offered after this portion has been consumed. Some substances we mix into the entire bulk of the morning feed. Keeping the compound too long in cheek pouches or spitting it out has never been a problem. We have used this simple oral administration technique for pharmacokinetic studies very successfully. Over a time period of 20 years, we have not had to deal with any substance that we could not feed to the vervets, including bitter herbal mixtures in fairly high concentrations.

This is an excellent method! Most facilities have made themselves dependent on commercial dry food, i.e., biscuits or chow that does not leave much leeway for creating a well-flavored paste that effectively masks commonly tested compounds.

When I treated diarrhea with metronidazole—a metallic tasting substance—in a large rhesus colony, nasogastric tubing was the only reliable, albeit stressful, method of administering the drug. Very few animals could be tricked into taking and swallowing the drug dissolved in peanut butter, jam, juice, or Ensure. Many of the animals seemed to accept the tablet when it was hidden in a grape, a piece of apple, a piece of banana or in a raisin, but they usually found out quickly what's going on, looked at me, pushed the tablet into the cheek pouch, checked the content of the cheek pouch carefully, and spit the pill out when I turned my back with the good feeling that the treatment was successful. The tablet then made its way to the sewer—and the animal continued to have chronic diarrhea. I finally habituated the animals to at least "tolerate" metronidazole treatment with the nasogastric tube in a transfer cage. You can even get adult males to sit still while you hold their heads and carefully insert the tube and administer the drug; but you "feel" that the animals are merely tolerating—not accepting—the treatment, and this makes the interaction quite tense and extremely risky for you. I would not recommend it to anybody except in a weekend-emergency case.

7,3,4. Pigs

I have great success in feeding pigs bitter pills such as buthorphanol, diazepam, and antibiotics by using snickers bars and concentrated Jell-O in liquid form—oddly the citrus flavors do not go over as well as strawberry, raspberry and cherry. The key is good acclimatization. If the animals know you are bringing tasty things, they will eat almost anything. Monkeys may be more challenging, as they are perhaps smarter than my piggie wiggies.

7,3,5. Conclusions

With gentle firmness, patience and professional skills most warm-blooded animals—with the exception perhaps of mice—can be habituated to tolerate oral dosing. Rabbits, rats, primates and pigs accept most drugs if these are mixed in specially flavored and specially prepared foodstuff that the animals really like and that masks unpleasant tastes of the drugs to be administered.

7,4. Pole-and-Collar Training of Macaques

I am currently pole-and-collar training one of our adult pair-housed rhesus females and hope that she will graduate to the chair in the next few weeks. Wendy does remain sitting when I move the pole towards her but squirms when I try to actually attach the pole to her collar. Can anyone offer some advice how to get over this hurdle?

The adult rhesus monkeys with whom I work also go through an initial period of resistance, when the pole is being attached and also, when they are then put into the chair. But they finally do settle down and cooperate. To start the training, I always first make sure that the trainee is so comfortable with me that she takes treats from my hand. I subsequently include the pole, offering treats with one hand, while holding the pole close to the cage in the other hand. The animals usually get used to this little ceremony very quickly and seem to ignore the pole, while focusing more on the treats.

The poles come with that handy little clip, opening and closing for collar attachment. The clip is a great place to hook treats, which the monkey can retrieve directly from the "dreaded pole." I stuff a marshmallow tightly into the clip. This makes it a little harder for the animal to get the treat and extends the time the animal is in contact with the pole. Once the treat is retrieved consistently without signs of apprehension or fear, I start moving the un-baited pole very carefully in the cage and, finally, also touch the animal with it. In subsequent sessions, I gently tap the collar with the pole, and when I am done hang it on the front door of the cage overnight, so that the animal gets more and more acquainted with it. Needless to say that extra rewards—jackpot if you feel it's deserved!—always are distributed at the end of each training session.

I always collar my rhesus macaques at least two weeks ahead of the first training session, so that they get used to wearing a collar all the time. If they're not comfortable with the collar, it really sets you back, because they will spend most of their time pulling at the collar and scratching their neck. I do not apply any enforced restriction when I train my animals; there is no squeeze-back. The trainee is always in control of the situation. I believe this greatly helps the animals to stay relaxed, keep trusting me and learn quickly what is expected from them in each training session. I consistently reward cooperation with a treat and with praise. If the animal doesn't cooperate, patience on my part replaces the reward. This strategy creates a tension-free ambience.

The first few times the pole is actually attached to the collar can be quite dramatic. The trainees usually freak out the moment they realize what is happening to them. But there is no reason for panic. I simply leave the pole attached and talk reassuringly to the animal who gradually will calm down, stop squirming and remain quiet long enough so that I can carefully unhook and remove the pole. This interaction is always followed by a generous treat reward, which is never refused. During the next sessions, I get the trainee to sit still with the pole attached to the collar for progressively extended periods of time, until she or he forgets all about the pole and takes treats from me. I repeat this step until I get the impression that the animal is comfortable with it.

Coaxing the poled monkey to get out of the cage is always a big challenge. After all, the familiar home cage is a relatively safe haven for these animals. But with patience and many reassuring words, the trainee does finally stop resisting and follows the pull of the pole. After a few sessions, the trainee will feel confident enough to walk—rather than struggle—on the pole and pick up treats from the floor. Should the animal begin to thrash about, I take the pole and carefully but firmly push the animal's head to the floor. To be clear, I do not throw him or her down, but rather use the pole to turn the collar up towards the animal's head and then apply some forward and downward pressure in a determined manner. The monkey is now fixed and can get his or her bearings while being safe from causing any serious problems, such as getting injured while jerking around. I have noticed over and over again that you can help the animal to calm down when you speak to him or her reassuringly with a gentle whisper-like voice. When the animal has settled down, I carefully start to walk him or her again.

It takes about one week of training until a monkey will cooperate and walk on the pole in a reasonably calm manner and pick up treats from the floor as a reward for good behavior. I want to get the trainees to walk, because after they come out of their cages—or out of the chair—they have a lot of pent-up energy that they like to release, especially the smaller guys. Their legs get cramped sometimes, and they really seem to like the opportunity to stretch. But, I treat this as a reward for good behavior. If they can calmly walk around, I let them do that, but if they start playing "super man," I pull them straight back into their cages. If you don't have enough space, or the racks are enticingly close for climbing and rattling cages, or if you are a little new at this and do not have a second person around who can help you control the monkey if need arises, the pole walking isn't a good idea.

Now, onto the chair:

  1. First, push the chair up against a wall with the opening facing out and put all the brakes on. This keeps the chair stable and makes it impossible for the animal to walk straight through, a situation that is really not fun when you're on the other end of the pole!
  2. Allow the monkey to explore the chair, touching it, climbing on it, walking around it and perhaps retrieving a treat that you have placed somewhere on the chair.
  3. After a day or so, coax the monkey into the sitting position in the chair, and don't forget to reward cooperative behavior!
  4. Gently lift the neck into position and get the collar into place. If another person, who is also on very good terms with the trainee, can help you, the situation becomes less of a challenge, especially when you are dealing with one of these incredibly strong and sometimes extremely stubborn guys.

Once you have your monkey in place, let him adjust for a few minutes. Don't forget the treats! Some animals will be initially restless and try to push your hand away, but with gentle patience they will all settle down and finally accept your food reward. Gradually extend the time the trainee remains in the chair, with you always being close by, serving as a comforting social support.

I have found that each "big step" involves an initial struggle, but I have also learned that with consistency and patience, the animals learn quite quickly what I expect them to do. I have a female who is fully trained and just comes up to the front of the cage without being squeezed and actually will move her collar, so the loop is exposed for me to attach the hook of the pole. This monkey also struggled a lot when I first started working with her. It is amazing how these animals can gradually relax into the training sessions and finally start working with you, rather than against you. Trust in the trainer is the ultimate key for success. These monkeys are smart and, when they are free of apprehension or fear, they quickly figure out that it is much easier and even rewarding for them to cooperate with you rather than resist. A successfully trained monkey will have developed so much trust in you that he or she will never fight against you when you pole and chair him or her.

When I train my animals, I work with them daily once or twice, five days a week, until the goal of the training has been achieved. If I don't work with them on a consistent schedule, they tend to get "rusty" quite quickly. The faster you can get them over the initial struggling, the easier the whole training will be. If you try to pole a monkey who vigorously resists on a Monday, and decide to wait and try again on Friday, chances are that the struggle will be the same; but if you are persistent and repeat this training step over and over again every day, you will definitely notice progress by the end of the week. I would imagine that without consistency and patience, the training would be a rather frustrating experience, both for the trainer and for the trainee.

To successfully pole-and-chair train a monkey is not necessarily a time-consuming process. My quickest subject took five days of consistent training to reliably cooperate. He was two years old and an angel! But I also have had some tough customers who have taken me well over a month to get going, especially cranky older females, who can be very stubborn and hard to food-motivate. Also, I have had some animals who were just never meant to be put in a chair. This is a reality that you and the investigators must acknowledge. You cannot force a monkey to cooperate and be relaxed in the chair. It's impossible. Sure, you can try, but you're not going to win.

I think we have to make it very clear to investigators who want us to train their animals that we cannot guarantee to be successful in all cases. Animals are not predictable machines. Yes, most monkeys can be trained but some cannot, or let's say they should not be trained because their personality—which is presumably conditioned through negative experiences with people—is very difficult to deal with. A monkey who persistently resists during positive reinforcement pole-and-collar-chair training is not a suitable candidate for research involving chair restraint. No investigator would benefit from having his or her research subject forced into an experimental situation such as chair restraint. The data collected from such an animal would be of little or no "scientific" value.

I wish all investigators could read this, understand it and accept it!

While strictly using positive reinforcement and applying patient gentle-firmness, most macaques can be trained to cooperate during the pole-attachment-chairing procedure. Some "cannot" be trained, because they have problems overcoming their often-legitimate mistrust of humans.

7,5. Catching Animals who have Escaped

What is the best strategy to capture animals who have escaped from their primary enclosure?

7,5,1. Monkeys

I was told by my supervisor that you have to chase escaped macaques until they get so exhausted that they will voluntarily go back into their cages. Supposedly, such a stressful experience will make it less likely that they will escape again in the future. I remember a student who was scolded for using an apple—since it was a "reward"—to lure a female rhesus back home after we had chased her around for 20 minutes. The monkey ate the apple and finally walked into her cage. The problem with using so much negative reinforcement was that it typically created quite a chaotic situation. Sometimes the animals in the cages got so excited that they started fighting with the escapee or even with their cage companions. We then ended up, with the veterinarian not only taking care of the injuries of the escapee, but also of fight wounds of other monkeys in the room.

I am staggered to hear that you chase them until they drop. A far better approach is to remain calm and quiet, preferably with only one person in the room. Since monkeys normally retreat from you, it's quite easy to make them move away from you into the direction of their home cage. It is my experience that they are usually only too pleased to get back home.

We had a singly housed rhesus male get loose this morning. He is one of our more grouchy monks with an attitude! He sat on top of the cages and made aggressive overtures towards me and my coworker. On two occasions, he instigated squabbles with some of the other monks in the room, but we were fortunately able to redirect his attention. Finally, through patience, nerve and a lot of praying to the macaque gods, we got the male to jump into an empty top cage into which we had thrown a bunch of fruit. It took about 15 minutes for this to happen. I was so relieved!

I have learned with group- and single-housed rhesus and stump-tailed macaques that catching animals who got loose can be a traumatic and chaotic event, but that it all depends on the personality of the attending care personnel. Some people freak out and create a real mess, shouting, scaring the escapee with broomsticks or trying to catch the escapee with a big net, while other people remain calm and quasi-mesmerize the disoriented monkey into entering a transfer cage, returning directly back into the home cage or jumping into an open empty cage baited with favored food.

Monkeys presumably escape not because they really want to leave their familiar home environment, but because something alarms them, such as an investigator trying to grab them with heavy leather gloves through the partially opened cage door. If they can trust you and you give them a chance to settle down, they will find their way back "home" without much coaxing—and you close the cage door, while praising the relieved monkey (Figure 60).

Figure 60  A good relationship with the monkeys—here a male rhesus macaque—and some basic knowledge of their behavior makes it relatively unproblematic for the attending care person to make an escaped animal go back to the home cage. Photo by Viktor Reinhardt.

We had over 40 rhesus monkeys get out of a corral, because a big branch fell over the wall, creating a perfect ladder. We noticed the situation first thing in the morning, so no one knew how long they were out. The reaction of the caretaker crew was to grab nets and dart guns. My thought was, "Are you crazy? The monkeys will all disperse; they know what nets are for." So, I convinced them to let me fill the corral with fruit and wait some time. And not surprisingly, within only a few hours, every one of the escapees jumped back into the corral and snatched a fruit. No one got distressed or injured. It was all so simple!

When one of our baboons escapes, we only have to place fruit in his open home cage. This always works, the escapee returns promptly, and the only thing we have to do is to quickly close the door of the cage. We stand as far from the cage as possible and toss the fruit into the empty cage, and then retreat, so as not interfere with the animals' route back home. We do have nets and a sedative dart gun but, fortunately, never had to use them.

Many years ago, I had some experiences with escaped squirrel monkeys. If you tried to catch a monk, the animal would inevitably hop across cage tops onto the floor, back up on top of a cage, across the cage tops, onto the floor, etc., predictably moving in the same pattern. The goal was then to keep the escapee going, with person #1 trying to catch him or her with the dreaded leather gloves. I—person #2—would don my gloves, memorize the route, stay out of the monkey's path, pick my spot, get my timing right, remain motionless, and only then make my catch. Being preoccupied with leaping and running around and being focused on person #1, an escaped monkey doesn't seem to actually see me. I would make my catch at the base of the tail and gently swing the monk into the waiting hands of person #1. It always worked, and I must confess, it was fun!

7,5,2. Rats and Mice

When rats or mice get out of their cages, we normally use a dustpan if the animals are scurrying on the floor—which they do most of the time. Most rodents, including guinea pigs, hamsters and gerbils, will run along the perimeter of a typical animal room offering no central shelter area. If you place the pan across the run, facing in the direction the critter is coming from, the escapee will run into it and happily sit there while you pick the pan up and safely and gently slide the animal back into the cage. This simple technique minimizes stress for the escaped rodent, eliminates the risk for the handler of being bitten, and it saves the elderly and arthritic amongst us having to get down on our hands and knees to awkwardly try to catch a swiftly moving, agile little animal. If rats or mice have escaped overnight, we usually find them sitting in the food hopper of a neighbor's cage, finishing off the food they haven't managed to transport back to the home cage during the night. Sometimes their home cage gets so filled up with chow from neighbors, that they can't get back into it. This scenario typically implies that the neighbors have bitten the tail and the feet of the scavenging escapee who, therefore, is relieved to be rescued by one of us.

Escaped mice and rats always try to stay as close as possible to the perimeter of the room. Typically, they are focused on moving and seem to be oblivious of my motionless figure hovering above, fingers poised to make the catch. They will come! And will cooperate! You only need to be patient and believe in your perceived outcome! It always horrified me, when the immediate reaction of the staff would be to move the racks, carts, food barrels, etc., while the rodents are scurrying around. Moving stuff only causes the escapees to run in an "unanticipated" direction, or to simply remain motionless to avoid detection, hence rendering any plan useless. Once the direction of the escapee's travel is established, these items make it easier to poise behind or next to, waiting for the inevitable moment when tail and fingers meet. I aim for the base of the tail and I am determined to be successful the first time. If you miss, plan again, anticipate, be patient, be still and be accurate! The trick is to keep the critters from learning a route that allows them to elude capture. Once they learn what's up, they become very savvy in testing your patience.

7,5,3. "Popcorn" Mice

We have a "popcorn" mouse issue. Investigators, using these jumpy little guys, are complaining that they are not breeding well and that mortality of adults is high due to their tendency to jump over staff shoulders as soon as the cage is opened. Husbandry staff are accidentally killing about one mouse per week. Your spontaneous reaction, when these critters start popping out of the cage, is to shut it quickly, which can unfortunately catch these fragile mice between the lid and the cage. I advise everyone dealing with 2 to 3-week-old mice to adopt a mellow, confident, quiet state of mind. The normal reaction is to think, "Oh no, a popcorn cage, here we go again!" and get nervous and impatient. It pays off when you can fight this reaction and stay calm and confident.

Our veterinarian came up with the idea to change "popcorn" mice cages inside a tall Rubbermaid barrel. Now, this isn't easy nor very comfortable, bending over a 1-meter barrel, but it does prevent escape! The mice can only jump about two-thirds of the barrel height.

I find paper or plastic tubes for enrichment very handy. It is my experience that a family of ten mice will shove themselves into a tube, making it unproblematic to relocate all of them to a new cage by just moving the "filled" tube to the new cage.

7,5,4. Conclusions

By applying basic ethological principles, escaped monkeys, rats and mice can be caught without unduly upsetting the escapee and other animals in the room. It is advisable to place cages of "popcorn" mice first into a container that the animals cannot jump out of and only then open the cage lid. Inevitably, the mice will now pop out, but they can be readily captured in this container.

7,6. How to Make Sheep Move

I have a bit of an urgent question for all of you. We are having problems leading our sheep from their housing quarters down to surgery. Currently we are using the poor system of hooking a leash around their necks and leading—sometimes dragging—them to the area. We worked with three sheep yesterday and have many more to come in the future. Yesterday's experience was very discouraging: The sheep vigorously pulled away from the lead, thereby almost strangulating themselves. Once they are coaxed into the transport cage, the animals are tied onto the side of the cage, which again makes them freak out. They struggle and try to get free and are at risk of hanging themselves in the process. It is horrible to watch and I cannot imagine what the sheep are going through! There has to be a better way; I was thinking of trying halters to lead them. That way, if they struggle, at least they will not hang themselves. Our next set of sheep are set for tomorrow. I really do not want to see a repeat of what happened yesterday!

You could consider training one individual as a "Judas" sheep—as used in some abattoirs—leading the test sheep into the crate. As long as you have no "Judas," you may want to make sure that you—the potential predator from which sheep would normally run away—do not try to "lead" the sheep but rather guide the sheep from behind. If you can provide a meandering path that the sheep can follow, they will be more inclined to walk in the desired direction.

Slightly squeezing the dock makes sheep move forward. The combination of the halter and the squeezing of the dock will probably be your best option, if your sheep must be handled alone. Sheep are downright terrified to be separated from other sheep, so they can hang themselves if secured by the neck only. The halter can be made of soft rope, and should fit over the bridge of the nose and behind the ears.

Sheep are best moved by guiding them from behind and allowing them to follow another sheep. If a sheep has to be moved alone, the combination of a well-designed halter and the gentle-and-firm squeezing of the animal's dock is probably the most efficient and safe option.

8. Safety Issues

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