Elimination behavior patterns of domestic cats (Felis catus) with and without elimination behavior problems

Wailani Sung Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

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Sharon L. Crowell-Davis Department of Anatomy and Radiology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602.

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Abstract

Objective—To investigate the relationship of litter box location as it relates to cats' use of space in the house, elimination problems, and certain behaviors associated with elimination.

Sample Population—40 cats in single-cat house-holds with or without elimination behavior problems (20 cats/group).

Procedures—Camcorders were used to record the cats' behaviors at the litter box and other areas in which they eliminated during a 72-hour period. Use of space in the house was recorded by direct observation during 400 minutes of the 72-hour period. Elimination behaviors and other cat- and litter box–associated variables were compared between groups; litter box location with respect to inappropriate elimination was assessed.

Results—Litter box location did not differ between cats with and without elimination behavior problems. An inverse correlation was found between time spent sniffing and the distance of the litter box from the central core area. Cats with elimination problems spent significantly less time digging at the litter box than cats without elimination problems. There was no significant difference in the time spent pawing in litter box, sniffing, or covering excreta after elimination between the 2 groups of cats.

Conclusions and Clinical Relevance—Times spent digging in litter boxes by cats with and without elimination problems have been determined, and data suggest that actual digging times could be used as a means to test for litter preference and litter aversion. This information may also be used to identify cats with litter aversion prior to the development of an elimination problem.

Abstract

Objective—To investigate the relationship of litter box location as it relates to cats' use of space in the house, elimination problems, and certain behaviors associated with elimination.

Sample Population—40 cats in single-cat house-holds with or without elimination behavior problems (20 cats/group).

Procedures—Camcorders were used to record the cats' behaviors at the litter box and other areas in which they eliminated during a 72-hour period. Use of space in the house was recorded by direct observation during 400 minutes of the 72-hour period. Elimination behaviors and other cat- and litter box–associated variables were compared between groups; litter box location with respect to inappropriate elimination was assessed.

Results—Litter box location did not differ between cats with and without elimination behavior problems. An inverse correlation was found between time spent sniffing and the distance of the litter box from the central core area. Cats with elimination problems spent significantly less time digging at the litter box than cats without elimination problems. There was no significant difference in the time spent pawing in litter box, sniffing, or covering excreta after elimination between the 2 groups of cats.

Conclusions and Clinical Relevance—Times spent digging in litter boxes by cats with and without elimination problems have been determined, and data suggest that actual digging times could be used as a means to test for litter preference and litter aversion. This information may also be used to identify cats with litter aversion prior to the development of an elimination problem.

Every year, an estimated 4 million domestic cats are euthanized in animal shelters.1 Cats with inappropriate elimination behavior problems had the highest risk of relinquishment. Approximately 23.5% of cats released to animal shelters had daily or weekly incidents of inappropriate elimination.1 The most common feline behavior problem evaluated in behavior clinics is inappropriate elimination; depending on the clinic, this type of problem may affect 59% to 79% of the feline patient population.2–6 Inappropriate elimination occurs when a cat eliminates in areas of the house other than its litter box.5,6 Behaviors that are considered to be part of inappropriate elimination are urine marking, urination, and defecation. A survey of 800 cat owners by Voith7 revealed that 11% complained of inappropriate urination by their cat. House soiling is an undesired behavior that can cause owners to abandon their cats if this behavior cannot be corrected.1

To understand why cats begin to eliminate in areas of the house other than their litter box, the cat's natural eliminative behavior must be studied. Cats that have inappropriate elimination behavior may have a medical problem, such as FUS or FLUTD.3,6,8 Both are caused by diseases of the lower portion of the urinary tract. Cystitis, calculi, urethritis, and urethral blockage are included in FUS and FLUTD. In cats, FUS (or FLUTD) is associated with frequent urination, which may not allow affected cats enough time to reach the litter box. Urination may also be painful for these cats; cats then associate pain with the litter box. Therefore, the cats avoid the litter box because of classical conditioning, even when they have recovered from the causative medical condition. However, many cats that perform house soiling do not have urinary tract disease, indicating other causes for this problem.3,9

Specific behavior patterns are evident when a cat defecates or urinates. Before urinating, a cat digs a hole in the ground with its forelimb feet and squats over the hole to express urine. Afterwards, the cat may or may not sniff the voided urine and cover it. A similar sequence occurs during defecation except that the cat does not squat as deeply as when it urinates.4,10 Examination of the sequence of these behaviors may provide more insight into the factors that predispose some cats to inappropriate elimination.8

There are several anecdotal reports3,6,11-13 that domestic cats living outdoors have a tendency to cover their feces and urine after they void within the core area of their home range. The home range is an area through which the cat normally travels in search of food, shelter, mates, and provisions for offspring.14 According to Worton,15 the home range is the area in which there is a 95% probability of locating a specific animal. In another study, Liberg16 determined that domestic cats always covered feces after defecation within their home yards, but did not cover feces after defecations in the fields. Similarly, free-ranging cats do not cover waste after they eliminate in the noncore area as frequently as they do in the core area12; core area was defined as the area of heaviest regular use. In a study17 of another population of free-ranging cats, elimination usually occurred in the noncore area rather than the core area. This behavior is in contrast to the behavior of canids, which scatter feces throughout their home range.18 Other researchers also determined that cats were more likely to bury waste after they eliminated within the core area.19

Incidents in which cats do not cover excreta after elimination in the litter box have led researchers to speculate on the possible causes. Various veterinarians8,20 have hypothesized that cats that do not cover after elimination may be more likely to engage in inappropriate elimination, compared with cats that do cover after elimination. Therefore, it is important to observe the sequence of behavior when a cat eliminates. A cat that does not dig before elimination or cover after elimination may be more likely to perform inappropriate elimination. In a survey by Horwitz,20 there was a significant difference in the covering behavior between cats that used the litter box and cats that did not use the litter box, as reported by owners. The survey data indicated that cats that engaged in inappropriate elimination were less likely to cover after elimination in the litter box.20

To our knowledge, the elimination behavior of domestic cats housed entirely indoors has not been previously studied by direct observation. Domestic cats are one of the few companion animals that can be easily trained to eliminate in a litter box within a household rather than eliminate freely within its surrounding environment. This behavior contrasts with the elimination behavior of free-ranging and feral cats, which have not been observed to have specific areas designated for elimination.21

One possible nonmedical cause of house soiling may be related to the location of the litter box in the household. Litter boxes are commonly placed in areas in which owners and cats do not spend a lot of time (eg, closets, bathrooms, and utility rooms); these locations may never be visited by cats for any purpose other than for use of the litter.5,9,22 Placement of the litter box in such locations may lead a cat to eliminate in areas outside the litter box rather than in an area designated by the owner. Another factor to consider is whether the litter box is placed in the core area. A litter box placed within the core area provides an area in which the cat can eliminate and cover excreta in a manner similar to that observed in free-ranging cats. Cats typically cover excreta after eliminating in the core area. A litter box placed within the core area would more likely be used. A litter box placed in the noncore area provides the cat a latrine location in which it is less likely to cover after elimination. Therefore, they may be more likely to use alternative sites for elimination than a litter box located in the noncore area. The location of the litter box in either core or noncore areas may have an important effect on where the cat chooses to eliminate. The purpose of the study reported here was to investigate the relationship of litter box location as it relates to cats' use of space in the house, elimination problems, and certain behaviors associated with elimination. There are several hypotheses that bear investigation. The location hypothesis suggests that litter box location is different between cats that develop inappropriate elimination behavior problems and cats that do not. Specifically, cats without problems will have the litter boxes located within the core area, and cats with problems will be more likely to have the litter boxes located within the noncore area. The core area hypothesis suggests that there is an inverse correlation between the time any cat spends digging, sniffing, covering, or pawing during elimination and the distance of the litter box from the central core area. The elimination behavior hypothesis suggests that there is a difference in elimination behavior at the litter box between cats with and without problems. Specifically, when they do use the litter box, the cats with problems will spend less time digging prior to elimination and covering after elimination than cats without problems.

Materials and Methods

Forty cats were studied; 20 did not have elimination behavior problems (nonproblem group), and 20 did have elimination behavior problems (problem group). Consenting owners and their cats were recruited in this study through referrals from local veterinarians, flyers on the campus bulletin boards, and newspaper advertisements.

For inclusion in the study, household cats had to be at least 1 year old and not more than 12 years old, clinically normal, and kept entirely indoors; there had to be only 1 cat in each household. Cats were considered clinically normal on the basis of results of physical examination, CBC, serum biochemical analyses, and urinalysis. For purposes of the study, cats that eliminated outside the litter box at least some of the time were defined as having elimination behavior problems.

In all households, a camcorder was positioned outside the litter box to record the sequence of behavior of each cat prior to and during elimination and the behavior exhibited afterwards. In households with a cat that had elimination behavior problems, a second (and if necessary, third) camcorder was used to record the pattern of behavior at areas outside the box in which the cat eliminated. The camcorder recorded continuously for 72 hours starting between the hours of 6:00 PM and 8:00 PM. The tapes were replaced once daily.

Durations of elimination-associated behaviors were recorded from the videotapes. These behaviors included covering (raking substrate over waste in litter box by use of the forelimb feet), digging (use of the forelimb feet to rake away substrate to form a shallow hole; may consist of a sequence of left and right or right and left foot movements), pawing (cat rubs feet over materials or objects other than the litter), and sniffing (nose held within 3 cm of object). Other factors that were also recorded included type of litter box (hooded vs not hooded), sex and age of cat, type of litter (clumping vs nonclumping; scented vs unscented), whether cat was declawed, whether cat was neutered, number of litter boxes in household, frequency of litter box cleaning, number of years the cat was owned, and the type of elimination behavior problem. The study focused on inappropriate urination on horizontal surfaces and defecation.

Four 100-minute samples were taken of each cat's use of space in the house. Every minute, the cat's location in the house was recorded on a map. One sample was recorded during each of the following time periods: 7:00 AM to 10:00 AM, 10:00 AM to 1:00 PM, 1:00 PM to 4:00 PM, and 4:00 PM to 7:00 PM. These data were used to determine the cat's home range and core area within the house.

Statistical analysis—Because the home range of each cat differed, the adaptive kernel method was used to calculate home ranges for each individual. This nonparametric method was chosen because the home ranges for each cat varied in distribution parameters. By use of the adaptive kernel method, all data points were plotted on a grid structure overlaid on the home range of each subject. The home range for each cat was calculated from a complete utilization distribution, which provided the relative frequency of the cat's locations over all observation periods.23 Home ranges obtained through use of the adaptive kernel method also provided a density estimate. The density estimate indicated the amount of time the cat spent in each area of the home range.24,25 The datum points were also used to determine the smallest area that accounted for 75% of the cat's area of activity; this was defined as the core area, which was the center of activity and the area of greatest utilization.26 The noncore area was the peripheral area that was less commonly used but was still part of the total home range.

To assess the location hypothesis, χ2 tests were used to determine whether there was a difference in litter box location between cats in the problem and nonproblem groups, whether the nonproblem group had litter boxes located disproportionately more within the core area than the noncore area, and whether the problem group had litter boxes located disproportionately more within the noncore area than the core area.

To assess the core area hypothesis, the area in which 10% of the cat's activity took place (ie, accounted to 10% of the datum points) was identified and defined as the central core area. The geographic center of the central core area was determined, and the distance from the geographic center to the litter box was measured. A Pearson correlation was used to test for the presence of an inverse correlation between the time each cat spent digging, sniffing, covering, or pawing during elimination and the distance of the litter box from the central core area.

To assess the elimination behavior hypothesis, a 1-tailed t test was used to test whether cats in the problem group would dig and cover less than cats in the nonproblem group.

Several variables were evaluated by use of a χ2 test to ensure that there was no significant difference in the distribution of variables other than those of focus between the nonproblem and problem groups. The variables included sex, age, neuter status, declaw status, and duration of ownership of cat; type of litter box; type of litter; number of litter boxes; and frequency of litter box cleaning. Overall, 10 c2 tests were performed and a Bonferroni correction was used for the P value. Thus, a significant effect was defined at a value of P < 0.005.

All data analyses were performed by use of statistics programs,a,b with a significant effect defined at a value of P < 0.05. Intraobserver reliability was calculated on the basis of 10 randomly selected samples.

Results

Complete videotape data sets were collected for most cats. Some short segments were missing because the owners turned the tape off for privacy. When this happened, data collected were adjusted to a 12-hour equivalent. Results of analyses to determine whether variables other than those of primary focus were affecting data indicated that there were no significant differences in those variables between the nonproblem and problem groups (Table 1).

Table 1—

Results of χ2 tests to assess differences in cat- and litter box–associated variables between cats with and without elimination behavior problems.

VariableProblem group (n = 20)Nonproblem group (20)χ2 Value (P value)
Sex
   Male770.00 (> 0.9)
   Female1313
Age (y)
   1–26125.00 (> 0.05)
   3–675
   7–922
   10–1251
Neuter status
   Neutered20191.03 (> 0.3)
   Sexually intact01
Declaw status
   Declawed11102.56 (> 0.2)
   Tendonectomy performed20
   Not declawed710
Duration of ownership (y)
   < 1347.00 (> 0.05)
   1–2411
   3–662
   ≥ 773
Type of litter box
   Hooded581.03 (> 0.3)
   Nonhooded1512
Type of litter
   Clumping11100.10 (> 0.7)
   Nonclumping910
Litter fragrance
   Scented11120.10 (> 0.7)
   Unscented98
No. of litter boxes
   118202.11 (> 0.1)
   > 120
Frequency of litter box cleaning
   ≥ 1 times a day991.04 (> 0.5)
   4–6 times a week10
   1–3 times a week1011

Assessment of the location hypothesis—In 37 of 40 households, the litter box was located in an area of the house that was not part of the cat's core area. Litter box location was not significantly different (χ2 = 73.0; P > 0.05) between nonproblem and problem groups. The nonproblem group had litter boxes located disproportionately more in the noncore area than was expected (χ2 = 139.26; P < 0.05). Similarly, the problem group had litter boxes located disproportionately more in the noncore area than the core area (χ2 = 52.267; P < 0.05).

Assessment of the core area hypothesis—There was an inverse correlation (P < 0.05) between sniffing and the distance of the litter box from the central core area (Figure 1); the closer the litter box was to the central core area, the more the cat sniffed (r = −0.318; P = 0.038). There was no significant correlation between distance of the litter box from the central core area and the amount of time spent digging (r = −0.146; P = 0.184), covering (r = −0.132; P = 0.208), or pawing (r = 0.067; P = 0.340) within the litter box.

Figure 1—
Figure 1—

Inverse correlation of the distance of the litter box from the central core area and duration of sniffing after elimination by cats with and without elimination behavior problems (20 cats/group).

Citation: American Journal of Veterinary Research 67, 9; 10.2460/ajvr.67.9.1500

Assessment of the elimination behavior hypothesis—Mean ± SE time spent digging was 12.4 ± 9.1 seconds for cats in the nonproblem group and 4.0 ± 3.8 seconds for cats in the problem group. Cats in the problem group spent significantly (t = 3.793; P = 0.002) less time digging in the litter box than did the control cats. Cats in the nonproblem group spent 15.7 ± 11.1 seconds covering after elimination, whereas cats in the problem group spent 9.8 ± 10.7 seconds covering. However, there was no significant (t = 1.709; P = 0.192) difference in the times that the 2 groups of cats spent covering in the litter box.

The mean number of occasions that cats eliminated per day was 5 for cats in the nonproblem group and 3 for the cats in the problem group. In the nonproblem and problem groups, mean time spent pawing after elimination in the litter box was 6.4 ± 7.8 seconds and 6.5 ± 11.3 seconds, respectively, and mean time spent sniffing after elimination in the litter box was 21.1 ± 8.9 seconds and 15.3 ± 11.7 seconds, respectively. Because there were no significant differences in duration of 3 of the behaviors (covering, pawing, and sniffing) between problem and nonproblem groups, the data from all 40 cats were pooled. Overall, mean time spent covering after elimination in the litter box was 12.8 ± 11.8 seconds, mean time spent pawing after elimination in the litter box was 6.5 ± 1.5 seconds, and mean time spent sniffing after elimination in the litter box was 18.2 ± 1.7 seconds. The intraobserver reliability, which was averaged over frequency, was 83% for sniffing, 100% for digging, 88% for covering, and 86.6% for pawing behaviors.

Discussion

Various factors may contribute to inappropriate elimination behavior problems in cats.4–6,9 The study of this report was performed to assess whether inappropriate elimination behavior in cats may be caused by the inappropriate location of the litter box in the household. It was expected that the location of the litter box would differ between cats that always used the litter box and cats that engaged in inappropriate elimination. However, results indicated that litter box location did not differ between cats with or without elimination behavior problems. This finding may suggest that the location of the litter box did not contribute to the cause of inappropriate elimination in the cats in the problem group. In 37 of 40 households in the present study, the litter box was located in an area of the house that was not part of the cat's core area. The litter box was unknowingly placed outside the core area by the owners. Therefore, the cats in our study usually did eliminate outside their core area.

The core area, as defined in the present study, may have included too much or too little of each cat's area of activity to accurately evaluate the importance of location. More research is needed to successfully identify a core area, which would include a latrine area. Further studies will be required to determine whether cats avoided spending time near the litter box (therefore, the litter box was not in the core area) or whether owners placed the litter box in areas that were not likely to be part of the cat's core area for reasons unrelated to elimination behavior.

There may be other motivating factors that contribute to a cat's litter box usage. One factor that may have an important effect on where a cat chooses to eliminate is the location of food and water; this aspect was not a focus of our study. A cat may prefer to have a latrine area closer to where it feeds, and this may be more important than having a latrine area closer to where it spends 75% of its time.

Data obtained from observing feral cats have suggested that cats behave differently before and after elimination depending upon the area in which they were eliminating. Liberg16 and Panaman12 reported that cats covered after elimination within the core area. When cats eliminated in areas outside the core area (noncore areas), they did not cover after elimination as frequently as they did after elimination in the core area. The results of the present study indicated that the time spent digging, covering, or pawing in the litter box was not greater when the litter box was located closer to the central core area; however, cats did engage in sniffing more frequently when the litter box was closer to the center of the core area. It has been determined that cats usually sniff places where feces are buried.19 Our data suggest that odors may be more relevant to cats in the central portion of their core area.

In 1 survey,20 many owners reported that their cats with inappropriate elimination problems did not dig prior to elimination in a litter box. The results of the present study support that finding, indicating that cats with inappropriate elimination problems do not spend as much time digging prior to elimination as do cats without inappropriate elimination problems. Because cats that always used the litter box spent more time digging in the substrate, failure to use the litter box appears to be substantially affected by variables that are likely to affect digging, such as substrate preference or aversion.

No difference in the time spent covering after elimination in the litter box between the problem and non-problem groups was detected. We had expected to find a difference in this behavior between the 2 groups. One reason that a difference was not detected may be that the litter boxes in both groups in our study were frequently located in the cats' noncore areas. Previous investigations12,16 have revealed that cats did not cover after eliminating outside the core area, but did cover when they were within the core area. Another explanation of why different results were obtained in the present study is that different definitions of core area may have been used in both previous investigations.12,16 In those studies, the core area was not specifically defined as the smallest area that accounted for 75% of the cat's area of activity. Another factor that may have affected the results was that all the cats in our study were kept entirely indoors, whereas the cats in the previous investigations were free-ranging cats living on farms.12,16 Therefore, 2 main factors (cats being housed indoors and owners choice of litter box location) may have affected the behaviors of the household cats included in the present study enough to produce results that differed from the results obtained for free-ranging cats.

In the study of this report, there was an even distribution of cats with intact claws and declawed cats in both the problem and nonproblem groups. There are no data from our study that support the idea that declawed cats have elimination behavior problems more frequently than cats that were not declawed.

Results of the present study have several implications for the treatment of inappropriate elimination behavior problems in cats. The finding that cats with such problems spent significantly less time digging in the litter box indicated that factors other than litter box location, such as litter aversion, substrate preference, box size, and frequency of litter box cleaning, may contribute to their preference to eliminate outside of the litter box.4–6,9 This study has delineated the digging times of cats with and without elimination behavior problems, but future studies should be performed to assess whether a cat's actual digging times can be used as a means to test for litter preference or aversion. Veterinarians can also ask clients to obtain digging time measurements of their cats with elimination behavior problems to better assess the relevance of this problem in their particular cat's case. The owners can then be instructed to obtain a substrate that their cats prefer to dig in or make other modifications in litter and litter box management.

For the households in the present study, the location of the litter box in the core or noncore areas, as defined, was not related to the presence or absence of elimination behavior problems. This finding does not provide conclusive evidence that litter box location does not affect where a cat chooses to eliminate. The study parameters may have differed from parameters set by previous researchers in this field; therefore, different results were obtained. It is impossible to determine whether this is the case because previous researchers did not report explicit definitions of core and noncore areas. Further studies that take into account the location of food and water and the exact distance of the litter box from the cat's central core area are needed to determine whether litter box location has an effect on a cat's usage of the litter box. However, it is hoped that information obtained from our study might be used to reduce the incidence of inappropriate elimination and the likelihood that cats will be relinquished to an animal shelter or euthanized because of inappropriate elimination behavior.

ABBREVIATIONS

FUS

Feline urologic syndrome

FLUTD

Feline lower urinary tract disease

a.

Statistical Analysis Software, version 8.2, SAS Institute Inc, Cary, NC.

b.

SPSS, version 11.0, SPSS Inc, Chicago, Ill.

References

  • 1

    Patronek GJ, Glickman LT & Beck AM, et al. Risk factors for relinquishment of cats to an animal shelter. J Am Vet Med Assoc 1996;209:582588.

  • 2

    Houpt KA. Housesoiling: treatment of a common feline problem. Vet Med 1991;86:10001006.

  • 3

    Olm DD, Houpt KA. Feline house-soiling problems. Appl Anim Behav Sci 1988;20:335345.

  • 4

    Borchelt PL, Voith VL. Elimination behavior problems in cats. Compend Contin Educ Pract Vet 1986;8:197205.

  • 5

    Halip JW, Luescher VA, McKeown DB. Inappropriate elimination in cats, part 1. Feline Pract 1992;20(4):1721.

  • 6

    Cooper LL. Feline inappropriate elimination. Vet Clin North Am Small Anim Pract 1997;27:569600.

  • 7

    Voith VL. Attachment of people to companion animals. Vet Clin North Am Small Anim Pract 1985;15:289295.

  • 8

    Overall KL. Feline elimination disorders. In:Clinical behavioral medicine for small animals. St Louis: Mosby Year Book Inc, 1997;160194.

    • Search Google Scholar
    • Export Citation
  • 9

    Beaver BV. Housesoiling by cats: a retrospective study of 120 cases. J Am Anim Hosp Assoc 1989;25:631637.

  • 10

    Beaver BV. Disorders of behavior. In:Sherding RG, ed.The cat: diseases and clinical management. New York: Churchill Livingstone Inc, 1989;163184.

    • Search Google Scholar
    • Export Citation
  • 11

    Beaver BVG. Feline behavioral problems. Vet Clin North Am Small Anim Pract 1976;6:333340.

  • 12

    Panaman R. Behaviour and ecology of free-ranging female farm cats (Felis catus L.). Z Tierpsychol 1981;56:5973.

  • 13

    Wolski TR. Social behavior of the cat. Vet Clin North Am Small Anim Pract 1982;12:693706.

  • 14

    Burt WH. Territoriality and home range concepts as applied to mammals. J Mammal 1943;24:346352.

  • 15

    Worton BJ. Using Monte Carlo simulation to evaluate kernel-based home range estimators. J Wildl Manage 1995;59:794800.

  • 16

    Liberg O. Spacing patterns in a population of rural free roaming domestic cats. Oikos 1980;35:336349.

  • 17

    Feldman HN. Methods of scent marking in the domestic cat. Can J Zool 1994;72:10931099.

  • 18

    Gorman ML, Trowbridge BJ. The role of odor in the social lives of carnivores. In:Gittleman JL, ed.Carnivore behavior, ecology and evolution. London: Chapman & Hall, 1989;5788.

    • Search Google Scholar
    • Export Citation
  • 19

    MacDonald D, Apps PJ & Carr GM, et al. Social dynamics, nursing coalitions and infanticide among farm cats, Felis catus. Adv Ethol 1987;28:164.

  • 20

    Horwitz DF. Behavioral and environmental factors associated with elimination behavior problems in cats: a retrospective study. Appl Anim Behav Sci 1997;52:129137.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21

    Mertens C, Schar R. Practical aspects of research on cats. In:Turner DC, Bateson P, ed.The domestic cat: the biology of its behaviour. Cambridge, England: Cambridge University Press, 1988;179192.

    • Search Google Scholar
    • Export Citation
  • 22

    Heidenberger E. Housing conditions and behavioural problems of indoor cats as assessed by their owners. Appl Anim Behav Sci 1997:52:345364.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23

    Van Winkle W. Comparison of several probabilistic homerange models. J Wildl Manage 1975;39:118123.

  • 24

    Seaman DE, Powell RA. An evaluation of the accuracy of kernel density estimators for home range analysis. Ecology 1996;77:20752085.

  • 25

    Seaman DE, Millspaugh JJ & Kernohan BJ, et al. Effects of sample size on kernel home range estimates. J Wildl Manage 1999;63:739747.

  • 26

    Mohr CO, Stumpf WA. Comparions of methods for calculating areas of animal activity. J Wildl Manage 1966;30:293304.

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