Biomedical Engineering Reference
In-Depth Information
TABLE 7.1
Prevalence of Abnormal Behavior by Taxonomic Group
% Surveyed Population
M. mulatta
a
(n
Behavior
P. troglodytes (n
¼
268)
¼
362)
Prosimians (n
¼
440)
Whole-body Stereotypies
b
Bouncing
17
b
Pacing
78
67
b
Rocking
27
22
b
b
Somersault
12
b
b
Posturing
7
Self-directed Stereotypies
b
b
Eye poke
0
b
b
Overgroom
3
b
Self-grasp
7
24
b
b
Self-suck
11
Appetitive Stereotypies
b
b
Coprophagy
39
b
b
Regurgitate
7
b
b
Urophagy
7
Self-injurious Behaviors
b
Hair-pulling
22
14
Self-injury
3
11
2
Original data and descriptions of individual behaviors were published elsewhere (P. troglodytes:
Nash et al., 1999; Fritz et al., 1992
; M. mulatta:
Lutz et al.,
2003
; Prosimians:
Tarou et al., 2005
).
a
Individually housed.
b
Not reported.
activities) and/or disruptive (interfering with biological
functions such as eating, breeding, or parental care); and (3)
severe: activities that produce bodily irritation or tissue
damage as in SIB. Only the latter two categories of
“substantial” and “severe” would require some form of
monitoring and intervention.
leading to different interpretations and interventions.
At one end of the continuum, stereotypic behavior is
viewed as maladaptive, indicating some level of distress,
whereas at the other end of the continuum, stereotypic
behavior is thought to reflect a coping strategy, the loss of
which might lead to distress. Below, we discuss possible
explanations for why animals engage in stereotypic
behavior including models that suggest that stereotypies
are either aversive or beneficial to well-being.
What is the Function of Stereotypic and
Other Abnormal Behaviors?
Although stereotypic behavior has been defined as lacking
any purpose or function, this view has increasingly come
under scrutiny. Based on research with rodents and farm
animals, several functional hypotheses have been offered
for why animals engage in stereotypic behavior (
Frith
and Done, 1990; Lawrence and Rushen, 1993; Mason and
Latham, 2004
). The proposed functions vary widely,
Maladaptive Models
Two models consider stereotypic behavior as a maladaptive
response reflecting underlying states of distress and poor
psychological and/or physical well-being. In the disease
model, stereotypic behavior is considered a symptom of
some underlying medical condition or illness (e.g. painful
conditions such as arthritis which can be associated with
