Biomedical Engineering Reference
In-Depth Information
training mangabeys to shift on command saved approxi-
mately one hour of technician time a day and that the initial
training investment was recovered within about a month.
Other procedures, such as weighing marmosets, takes
significantly less time with trained monkeys than untrained
monkeys (
McKinley et al., 2003
).
PRT as Enrichment
Training can also be an effective form of occupational
enrichment. PRT was found to reduce the incidence of
stereotypies in several NHP species (
Raper et al., 2002;
Bourgeois and Brent, 2005; Coleman and Maier, 2010
),
although this is not a universal finding (
Baker et al., 2009
).
Further, training can be used to decrease aggression in
group-housed animals. Bloomsmith and colleagues
(
Bloomsmith et al., 1994
) used cooperative feeding tech-
niques to train dominant chimpanzees to remain stationary
during feeding time and allow subordinates to feed, thus
decreasing food-related aggression.
FIGURE 6.5
Adult male rhesus macaque (
Macaca mulatta
) with arm
in blood sleeve. The monkey was trained to put his arm in the blood
sleeve and hold onto the peg at the distal end until released by the trainer.
(Photo reprinted from Coleman et al. (2008, figure 1, p. 38) with
permission from the Journal of the American Association of Laboratory
Animal Science.)
In this case,
the
dominant
animals
received
extra
treats
for
their
cooperation.
Fewer studies have examined the efficacy of PRT on
promoting normal behavior. PRT has been shown to
increase prosocial behavior in group-housed chimpanzees
(
Pomerantz and Terkel, 2009
) and baboons (
Desmond,
1994
) in a zoo setting. It has also been used to promote
social behavior (e.g. grooming and play) in group-housed
rhesus macaques (
Schapiro et al., 2001
). In this study,
female rhesus were categorized as either “high affiliators”
or “low affiliators” based on their level of social interaction.
PRT was used to successfully train the “low affiliators” to
move closer to and engage in social behavior with other
group members. These effects extended to periods beyond
the actual training sessions (
Schapiro et al., 2001
).
While there are many benefits associated with estab-
lishing a positive-reinforcement training program for
nonhuman primates, there can be inherent difficulties as
well. Training often involves an initial investment of time
and monetary resources. In addition, there is a great deal of
variation among individual NHPs with respect to their
training potential. Some subjects are relatively easy to train
and learn tasks quickly, whereas others require significantly
more time and effort. These differences may be especially
problematic if research protocols require all subjects to be
trained. There are interspecific differences in behavior that
can affect how individuals learn tasks (
Savastano et al.,
2003
). In addition, there are also intraspecific differences in
learning abilities among individuals. Monkeys have unique
personalities, and strategies that work for one individual
may not work for all. For example, monkeys with relatively
short attention spans may do better with shorter, more
frequent training sessions (
Savastano et al., 2003
). Shy
animals can be more difficult to train than more exploratory
animal(s) from one area to another. Shifting can take many
forms, including large groups moving on command from
their indoor enclosure to their outdoor enclosure or indi-
vidual animals moving from their home cage to a transfer
box. A variety of species have been trained to shift,
including marmosets (
McKinley et al., 2003
), chimpanzees
(
Bloomsmith et al., 1998
), and mangabeys (
Veeder et al.,
2009
). Primates have also been trained to: (1) come to the
front of the cage or enclosure; (2) present a specific body
part; and (3) remain stationary for veterinary or research
procedures, such as an injection (
Priest, 1991; Videan et al.,
2005
), a medical exam (
Schapiro et al., 2005
), or blood
pressure measurement (
Turkkan, 1990
). Primates have
been trained to take oral medication (
Klaiber-Schuh and
Welker, 1997
), and to give semen or urine samples
(
Schapiro et al., 2005
). Both rhesus monkeys and chim-
panzees have been trained to put an arm in a blood sleeve
and remain stationary for venipuncture (
Coleman et al.,
2008
,
Figure 6.5
). In this study, both the rhesus and
chimpanzees reliably performed this task after approxi-
mately 6 months of focused training.
Not only does training reduce stress for the animals, but
it can also reduce stress for the people working with the
animals. Working with cooperative animals is safer and less
time-consuming for caregivers and technicians than is
working with highly stressed and potentially reactive
animals (
Bloomsmith, 1992
). While training can initially
be time-consuming, the time invested is likely to be
recovered once the animals are trained. For example,
Veeder and colleagues (
Veeder et al., 2009
) found that
