Table 3 Individual Spearman rank correlation coefficients for cephalocaudal sequencing of oral grooming bouts
Subject Coefficient
1 0.21
2 0.71
3 0.22
4 0.15
5 0.16
6 0.43
7 0.08
8 0.40
9 y0.04
10 0.25
11 0.46
was a cephalocaudal trend. The mean Spearman correlation coefficient of all subjects for cephalocaudal sequencing of oral grooming was 0.21, which was significant at p - 0.01.
Although there was considerable individual variation in the correlation coefficients Ž
among subjects, all but one of the subjects had a positive correlation coefficient Table .
3 . The Spearman correlation test of sleeprrest duration and latency to the next oral
Ž .
grooming bout revealed a negative and significant correlation r s y0.167, p - 0.05 . Among the 11 subjects, eight had negative coefficients, two positive coefficients and
one a coefficient of 0.
3. Experiment 2: effects of grooming deprivation
Experiment 1 provided an indication that cats have an increased tendency to perform oral grooming following a period of sleeprrest. To acquire more definitive information
about whether a deprivation of grooming leads to a compensatory enhancement, this experiment involved 3 days of enforced deprivation of grooming. To preclude the
possibility that ectoparasites might accumulate and stimulate grooming, this experiment was conducted with cats in ectoparasite-free environments.
3.1. Methods 3.1.1. Subjects
Ž Nine cats kept as household pets by veterinary students were recruited five neutered
. males, four spayed females, ages 1–8 years . All subjects were indoor cats from
households with no history of ectoparasite infestation. Additionally, subjects were examined with a flea comb at the start of the study to confirm the absence of flea
infestation.
3.1.2. Experimental design In a repeated measures design, each subject served as its own control. For 3 days,
Ž each cat wore either an Elizabethan collar E-collar, of the type used in veterinary
. practice to control excessive licking that prevented oral grooming and scratch grooming
Ž .
of the head scratch grooming could still occur caudal to the collar , or a control collar, 1.0 cm wide, that did not prevent grooming. The collared cats were allowed to move
about freely in the home and preliminary observations revealed the E-collar did not affect eating, sleeping or resting behaviour. When the collars were removed 3 days later,
Ž .
the subjects were immediately placed in an observation cage 61 = 96 = 127 cm high in the home and videotaped continuously for the next 24 h. The procedure was then
repeated for each subject with the alternative collar. Four of the nine subjects wore the control collar first, and five wore the E-collar first.
3.1.3. Analysis The 24-h time-lapse videotapes were analyzed for all grooming activity including
frequency and duration of oral and scratch grooming bouts. As in Experiment 1, each oral grooming bout was categorized as being directed to multiple regions or a single
region. A grooming bout was considered terminated when a non-grooming activity Ž
. occurred e.g., eating, eliminating, rest , or if more than 60 s elapsed without a licking
episode. As in Experiment 1, separate start and stop times were entered if more than 5 s of non-grooming followed a grooming episode within a grooming bout. The observer of
the videotape did not know whether the cat had been wearing the E-collar or the control collar prior to being placed in the observation cage.
Because preliminary observations suggested that the difference in grooming rates following removal of E-collar would occur within the first few hours after collar
removal, the 24-h observation period was divided into two 12-h periods to derive an estimate of the duration of the grooming enhancement. The non-parametric Wilcoxon
signed rank test was used to test for statistical significance with the level of significance set at 0.05. A one-tailed test was used because the prediction was that grooming would
increase following restraint of grooming.
3.2. Results In the initial 12 h following removal of the E-collar, cats orally groomed a mean of
Ž 67 more than when they had been wearing the control collar the increase was
. significant, p - 0.05 . In the second 12 h, there was not a significant difference between
Ž .
the two conditions Fig. 1 . Also there was more than a twofold increase in time spent in scratch grooming in the first 12 h following removal of the E-collars compared with
Ž .
removal of the control collars p - 0.01 , and again there was no difference during the
Ž .
second 12 h Fig. 1 . The enhancement of oral grooming in the first 12 h was due to an Ž
increase in both bout frequency and bout duration neither of which alone reached .
significance . There was no significant change in the proportion of grooming distributed to multiple vs. single regions. Grooming of multiple regions was a mean of 92 in the
control situation and 96 following E-collar removal. Both scratch grooming bout
Ž .
Ž . Fig. 1. Mean SEM time spent in oral and scratch grooming following removal of control collars C or
Ž . E-collars E for the first and second 12-h periods immediately after collar removal. The difference between
the control and E-collar condition was significant for oral and scratch grooming for the first 12 h but not the second 12 h.
frequency and bout duration were significantly increased in the first 12 h following Ž
. E-collar removal
p - 0.05 .
4. Discussion
