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Animals 2021, 11, 253. https://doi.org/10.3390/ani11020253 www.mdpi.com/journal/animals
Article
Indoors or Outdoors? An International Exploration of Owner
Demographics and Decision Making Associated with Lifestyle
of Pet Cats
Rachel Foreman-Worsley
1,
*, Lauren R. Finka
1
, Samantha J. Ward
1
and Mark J. Farnworth
1,2
1
Brackenhurst Campus, School of Animal, Rural and Environmental Sciences, Nottingham Trent University,
Nottinghamshire NG25 0QF, UK; lauren.finka@ntu.ac.uk (L.F.); Samantha.ward@ntu.ac.uk (S.W.);
v1mfarnw@exseed.ed.ac.uk (M.F.)
2
Jeanne Marchig International Centre for Animal Welfare Education, Easter Bush Campus,
Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian EH25 9RG, UK
* Correspondence: rae.foreman@ntu.ac.uk
Simple Summary: Owners may consider many factors when deciding whether to provide an
indoor-only or indoor-outdoor lifestyle for their cats. These include safety, mental and physical
health, exposure to parasites or disease, and depredation of wildlife. This international study used
a series of online surveys to explore the factors cat owners consider when deciding what lifestyle to
provide for their cat, alongside investigating if owner and cat features are associated with greater
odds of cats having indoor-only or indoor-outdoor lifestyles. Ten variables were found to be
significant predictors of lifestyle. Owner features predicting a greater likelihood of cats being kept
as indoor-only were being 26–35 years old, having multiple cats, living in city centres or urban areas,
and living in the United States, Canada, Australia, or New Zealand. For cats, these features included
being junior, having health issues, being pedigree, or having unknown pedigree status. Owner
features predicting a greater likelihood of cats being indoor-outdoor were owners being 46–55+
years old or 56+ years old and having children (17 years old or under) living at home. For cats,
features included being male and being mature or senior. Road traffic accidents were the major
concern for owners of indoor-only cats in all regions surveyed. Owners who provided outdoor
access predominantly indicated they did so for the mental wellbeing of their cat. These findings are
important in understanding the considerations owners give to their cat’s lifestyle and identifying
management trends and cat populations potentially at risk of compromised welfare due to
unsuitable lifestyles.
Abstract: Outdoor access for owned domestic cats (Felis catus) is a divisive issue. Cat safety, mental
and physical wellbeing, infectious diseases, and wildlife depredation are cited as factors influencing
owners; however, the degree of consideration each factor receives has not been quantified. This
study (i) analysed which demographic variables are associated with greater odds of cats having
indoor or outdoor lifestyles, (ii) identified which factors owners consider when making a choice on
lifestyle and any regional variations, and (iii) identified if owners consider the different lifestyle
options available and recognise their associated benefits. A series of online surveys were used for
data collection. Binary logistic regression models were used to generate odds ratios assessing if
demographic variables were significantly associated with cat lifestyle. Quantitative analysis of
factors considered when deciding on cat lifestyle was accompanied by a thematic analysis of rich-
text open-ended responses, providing nuanced insight into the rationale and elucidating additional
factors considered. Of the demographic variables tested, 10/12 were significantly associated with
lifestyle. Variables with higher odds of indoor-only lifestyles were owners being 26–35 years old,
multi-cat households, junior cats, pedigree cats or unknown pedigree status, cats with health issues,
living in city centres or urban areas, or living in the United States, Canada, Australia, or New
Zealand. Variables with higher odds of indoor-outdoor lifestyles were owners being 46–55 years
old or 56+ years old, households with residents 17 years old or under, male cats, and cats being
Citation: Foreman-Worsley, R.;
Finka, L.R.; Ward, S.J.; Farnworth,
M.J. Indoors or Outdoors? An
International Exploration of Owner
Demographics and Decision Making
Associated with Lifestyle of Pet Cats.
Animals
2021, 11, 253. https://doi.org/
10.3390/ani11020253
Received: 17 December 2020
Accepted: 18 January 2021
Published: 20 January 2021
Publisher’s Note: MDPI stays
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Copyright: © 2021 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license
(http://creativecommons.org/licenses
/by/4.0/).
Animals 2021, 11, 253 2 of 26
mature or senior. Road traffic concerns were the most cited reason for keeping indoor-only cats
across all global regions. The second-most cited reason varied regionally. For Europe, it was
protection from people. For the USA and Canada, the reason was protection from wildlife, and for
Australia and New Zealand, to prevent hunting. Indoor-outdoor cat owners cited most frequently
the benefits to their cat’s mental health. Over two-thirds of owners did not consider the alternative
lifestyle for their cat. These data give insight into the priorities of cat owners with regards to feline
wellbeing, feline safety, and wildlife depredation, helpful for individuals or organisations working
with human behaviour change. They provide evidence that the numbers of indoor-only cats are
likely to rise with increasing urbanisation. Finally, the data identify cat populations who may be at
risk of compromised welfare due to unsuitable, or under-researched, lifestyles.
Keywords: cats; felines; indoor-only; indoor-outdoor; companion animal; Felis catus; management
1. Introduction
The provision of outdoor access for domestic cats (Felis catus) by their owners is a
divisive issue [1,2] and likely influenced by cultural norms. In the United States of
America (USA), 63% of domestic cats are kept entirely indoors [3]. In contrast, many
European countries, including the United Kingdom (UK) [4] and Denmark [5], as well as
Australia [6,7], typically provide owned domestic cats with outdoor access, in addition to
allowing them to occupy the house. There is, however, a growing trend towards keeping
cats exclusively indoors. The UK is seeing a rapid increase in the number of indoor-only
cats, with the PDSA (People’s Dispensary for Sick Animals) producing estimates of 15%
in 2011, increasing to 24% in 2015 [4], and a more recent UK study indicating 26.1% in
2019 [8].
At present, very little information exists regarding the factors that owners consider
when deciding on a lifestyle for their cat, the weight owners assign to these factors, or if
specific cat and owner demographic variables are associated with different lifestyles. This
information could be of benefit to organisations, charities, or individuals to maximise the
efficacy of human behaviour change incentives. It may also help to explain changes in cat
management trends globally and predict how management trends may continue to
change in the future.
For this study, a survey was distributed to an international population of current cat
owners, exploring the rationales behind lifestyle choices for cats. To help inform survey
questions, an initial overview of the current literature surrounding the factors that owners
may consider when making a lifestyle decision for their cat was generated. This review is
presented below.
1.1. Lifestyle Considerations
Hunting: Domestication of the cat was driven by their predatory nature, which was
advantageous for pest control in early agricultural communities [9]. Since then, cats have
experienced a relatively unique domestication process involving less intensive selection
than animals such as dogs [10]. Consequently, most domestic cats have retained ancestral
behavioural motivations, such as hunting drive irrespective of food provision [11]. Whilst
hunting behaviour is still valued in some agricultural contexts, it is not typically valued
by owners keeping cats as companions [12,13]. On the contrary, predatory behaviours are
of growing concern as the numbers of domestic cats rise due to their impacts on native
wildlife including birds, invertebrates, mammals, and amphibians [14,15]. The ecological
impact of hunting on wildlife appears to vary between areas. More severe damage to
ecosystems is thought to occur where cats represent an introduced predator and where
wildlife has not evolved to avoid predation, such as Australia, New Zealand, or remote
islands. In some such instances, cats have been credited as contributors to the extirpation
Animals 2021, 11, 253 3 of 26
or near-extirpation of species [16–18]. Consequently, some owners, at the behest of
wildlife charities and veterinarians, opt to keep cats indoors to prevent hunting [19]. It is
possible that concerns over impact severity may influence the consideration given to
hunting by owners. For example, UK cat owners generally disagree that cats are harmful
to wildlife, regardless of the predatory behaviour of their cat [20]. In Australia and New
Zealand, however, 62% and 51% of cat owners, respectively, agree that predation is
problematic [13].
Cat safety: Outdoors, road-traffic accidents (RTAs) are likely a major concern to cat
owners. A UK study found the major cause of mortality for cats brought into a veterinary
clinic was trauma, 60% of which were identified as RTAs [21]. An estimated 12% of cats
in Cambridgeshire, UK had been involved in an RTA and survived [22], suggesting a
higher percentage of cats are involved in RTAs in total when also accounting for
mortalities. Additional outdoor risks include attacks by humans, and where feral cats are
considered as pests and lethally controlled, domestic cats may risk being indiscriminately
killed through poisoning [23] or other pest control methods. There is also the potential to
consume toxins such as pesticides, insecticides, anti-freeze, or toxic outdoor plants.
Indoors, cats may ingest toxic substances, such as cleaning products, houseplants or
flowers, medicines, or toxic food substances [24], or risk electrocution from household
appliances. Both indoors and outdoors, there is a possibility of injuries or bites from wild
and domesticated animals, including other cats [25].
Physical health: A positive correlation between obesity in cats and an indoor-only
lifestyle has been demonstrated, with potential mechanisms cited as being a reduced
physical activity, greater consumption of food through boredom, and lack of enrichment
[26–28]. Obesity, reduced activity, and toileting exclusively indoors have also been
associated with increased risk of feline urological syndrome (FUS) [29]. It is possible some
owners may utilise outdoor access as a weight management tool. Outdoors, however, cats
are at greater risk of contracting diseases such as feline immunodeficiency virus (FIV),
feline leukaemia virus (FeLV), ringworm and cat flu, or parasites due to their contact with
wildlife and other domestic cats [30]. Owners may wish to reduce these risks to improve
welfare or prevent associated veterinary treatment or zoonotic transmission.
Additionally, owners of cats with contagious diseases may choose to house their cats
indoor-only to prevent disease transmission to other cats.
Mental well-being: Many behavioural needs of cats, such as hunting, territorial
patrolling and marking, roaming, and climbing may be more readily met in an outdoor
environment [11]. Whilst owners may instead aim to meet their cat’s behavioural needs
indoors, studies suggest many cat owners may not provide adequate levels of enrichment
to ensure high welfare for their cat [31–33]. Insufficient levels of enrichment and the
inability to avoid stressful human–social environments indoors [34,35] may contribute
towards the comparatively higher levels of undesirable and sickness behaviours observed
in indoor-only cats, compared to indoor-outdoor cats [5,8,36–38], although it has been
reported in one instance that indoor-outdoor cats may display more undesirable
behaviours [31]. With regards to owner attitudes, an Australian study revealed most
indoor-outdoor cat owners felt wandering was natural and necessary for cats to be
‘happy’ [19]. In the USA, owners were mixed in their response when asked if cats needed
time outdoors to be ‘happy’ [31]. In a Brazilian study, just 7.5% of owners felt it was
necessary for cats to have outdoor access [39]. Whilst owners may perceive some aspects
of outdoor access as beneficial to cat mental health, it must be considered that owners
interpret other aspects as detrimental, lest their cats perceive potential dangers, novel
environments, sights, and sounds or territorial conflicts with conspecifics negatively.
Animals 2021, 11, 253 4 of 26
1.2. Aims and Objectives
Identify if different owner features or cat demographics are associated with greater
odds of cats having an indoor-only or indoor-outdoor lifestyle;
Elucidate the extent to which factors identified from the literature influence owners
when making lifestyle decisions for their cat, and what proportion of owners
consider the different lifestyle options available;
Establish major narrative themes around owner decision making.
2. Materials and Methods
2.1. Survey Creation and Distribution
An initial online survey (part 1) for cat owners was distributed in English via social
media, predominantly Facebook and Twitter, between February 2019 and April 2019. It
purposively sampled cat owners using relevant social media groups and cat-related
hashtags. To participate, respondents needed to be 18 years old or over and the current
owner of at least one cat which did not live exclusively outdoors. The survey comprised
of the following sections: owner demographics, cat demographics, cat health and
behaviour (including both sickness and undesirable behaviours), cat personality, cat
lifestyle (indoor-outdoor or indoor-only) and the basic rationale for said lifestyle, home
environment inclusive of basic provisions and enrichment and social behaviour with
adults, children, and cats and dogs within the household. Questions consisted of multiple
and single choice questions, Likert scales, and open-ended text-based questions. The
survey was developed as part of a wider study looking at cat management and welfare,
of which a subset of data is considered for the purposes of this paper.
Participants who responded to the initial survey (part 1) and had provided an email
address were sent a second survey (part 2) exploring the rationale for choosing an indoor-
only or indoor-outdoor lifestyle for their cat. Through a series of questions, owners were
asked to identify factors influencing their decision and the strength of their consideration
using Likert scales. Part 2 also established if owners of indoor-only cats had considered
outdoor access and vice versa and identified the strength of consideration given to aspects
of the alternative lifestyle. Respondents were encouraged to leave as many details as
possible in open-ended questions. Owners of both indoor-only and indoor-outdoor cats
answered the same questions, reworded to be appropriate to each group. Responses from
part 1 and part 2 were matched using email addresses, so demographic data could be
associated with rationales.
Ethical approval was given by Nottingham Trent University School of Animal, Rural
and Environmental Sciences Research and Ethics Committee on the 11
th
December 2018
(ARE843).
2.2. Data Cleaning
Owners who indicated they intended to change their cat’s lifestyle were excluded
from the analysis (n = 34). These owners detailed reasons such as recently acquiring their
cat, recently moving to a new house, or having a cat they deemed as currently too young
to roam, including those awaiting neutering. Owners providing different answers for
their cats’ lifestyles for part 1 and part 2 of the survey but who had not indicated they had
changed their cat’s lifestyle were excluded to avoid reporting errors by respondents (n =
16). Finally, those who had categorised their cat as having one lifestyle but provided
contradictory comments were excluded (n = 43), e.g., one owner indicated their cat was
indoor-only but commented, ‘The cat does have some supervised time outside […]’.
Owners were categorised into three major regions—Europe, USA and Canada, and
Australia and New Zealand. Other regions were excluded from analyses due to low
sample sizes (n = 154). These regions were chosen to compare attitudes towards cat
management which might be influenced by variations in local legislation and
recommendations from regional feline welfare charities [40–42].
Animals 2021, 11, 253 5 of 26
2.3. Data Analysis
Responses were divided into populations of owners providing their cats with either
an indoor-only or indoor-outdoor lifestyle. A combination of Microsoft Excel (Version
2002, Microsoft, Washington, DC, USA) and IBM SPSS (Version 26, New York, NY, USA)
was used to generate descriptive statistics exploring the demographics of cats with
different lifestyles. Descriptive statistics were also used to gain insight into the frequency
of responses from quantitative multiple-choice questions.
Open-ended responses were read in their entirety by the lead author, RFW. A portion
of open responses directly reflected the multiple-choice answers provided and was coded
as such. Responses that did not fit existing answers were classed as ‘other’ reasons within
quantitative analyses. These ‘other’ responses were taken forward to an additional
qualitative thematic analysis and coded as new semantic themes, using the six-phase
methodology defined by Braun and Clarke [43]. In keeping with qualitative methods and
considering that responses were optional and therefore not balanced amongst key owner
and cat demographic variables, themes were not quantified. Themes and example
responses are instead provided to allow insight into the wide range of factors owners may
consider when choosing their cats’ lifestyle, alongside the depth of thought and emotion
behind these considerations.
2.4. Odds Ratios
Demographic variables hypothesised to have biological relevance to owner decisions
on cat lifestyle choice were explored using binary logistic regression modelling. Odds
ratios were calculated to elucidate if specific variables predicted a greater likelihood of an
indoor-outdoor or indoor-only lifestyle. Three models were produced, each with ‘lifestyle’
as the response variable.
Model one explored associations between lifestyle and owner social features, with
explanatory variables of owner gender, owner age, and the number of other cats, dogs,
and children (17 years old and under) in the home. It was hypothesised that owners of
different generations with differing levels of social intensity within their homes may make
different lifestyle choices for their cats.
Model two’s explanatory variables were cat features of age, sex, ongoing health
issues, and pedigree status. It was hypothesised owners may make decisions based on the
specific characteristics of their cat and what they deemed to be the most appropriate
lifestyle for that individual. Cat ages were categorised into life stages for analysis, based
on definitions provided by Vogt et al. [44], which are as follows: kitten, 0–6 months old;
junior, 7 months–2 years old; adult, 3–6 years old; mature, 7–10 years old; senior, 11–14
years old; super senior, 15+ years old. Due to the small numbers of super senior cats in the
sample, these cats were grouped with senior cats to create a senior category of 11+ years
old. Neutering, microchipping, vaccinating, and declawing were not deemed to be
biologically relevant explanatory variables for this model. It was deemed more plausible
that lifestyle choice would impact the decision of owners to provide such treatments to
their cats, rather than vice versa.
Model three explored geographic features and consisted of explanatory variables of
the global region, area type, e.g., rural, urban, etc.; and dwelling type, e.g., flat/apartment,
detached house, etc. It was hypothesised that differing cultural norms may impact
lifestyle choices between regions, and that area and dwelling type may influence owners
based on the availability and quality of outdoor access.
Reference categories were set as the normative categories. For owner gender, cat sex,
owner and cat age, region, area, and dwelling type these were the variable category with
the largest portion of respondents. For the presence of other cats, dogs, under 17-year-
olds, health issues, or pedigree status, the reference categories were set as ‘no’.
Due to small group sizes making for unbalanced categories, excluded from the
analysis were owners who had indicated ‘prefer not to say’ for either age or gender,
Animals 2021, 11, 253 6 of 26
owners identifying as ‘other’ for gender, owners unsure of their cats’ sex or age, owners
living in movable homes such as motorhomes or barges, one owner who indicated they
lived in a Souterrain (cellar), and kittens <6 months old. If responses were excluded, they
were excluded across all three models. In total, 4909 samples out of the original 5129 were
analysed.
3. Results
From the first part of the survey, 5129 responses were included. Part 2, exploring
lifestyle rationales in more depth, was emailed to a subsample of those participants
(2581/5129) and returned by 459/1071 of indoor-only respondents (response rate 46.4%)
and 595/1510 of indoor-outdoor respondents (response rate 39.4%). As not every question
was answered by all participants due to survey routing, the number of respondents is
detailed with each result presented within this section.
3.1. Demographic Results
Of the initial 5129 survey respondents (prior to those excluded for the odd ratios
analysis), most respondents were female (89.1%), 26–35 years old (28.2%), had no children
under 17 years old living with them (80.4%), owned more than one cat (55.3%), and had
no dogs (81.8%). Most respondents lived in Europe (76.2%), falling across 36 European
countries in total, although the majority were UK-based (80.3%). A full breakdown of
owner demographics can be seen in Table 1, divided into populations of owners that
provided either indoor-only or indoor-outdoor environments for their cats.
Animals 2021, 11, 253 7 of 26
Table 1. Owner demographics and their living environments of the 5129 respondents. Percentages for the entire group of
respondents are shown, as are the breakdowns between those who indicated their cat had an indoor-only (n = 2104) or
indoor-outdoor lifestyle (n = 3025).
Owner
Demographics Categories
Proportion of Total
Population (%) (n =
5129)
Proportion of Indoor-
Only Population (%) (n =
2104)
Proportion of Indoor-
Outdoor Population (%) (
n
= 3025)
Owner gender
Female 89.1 87.9 89.9
Male 9 9.5 8.7
Other 1.2 1.9 0.7
Prefer not to say 0.7 0.7 0.8
Owner age
18–25 14.1 14.3 14
26–35 28.2 33.2 24.8
36–45 23.7 23.2 24
46–55 20 17.5 21.8
56+
12.6 11.5 15
Prefer not to say 0.4 0.3 0.5
Other cats No 44.7 41.8 46.6
Yes 55.3 58.2 53.4
Dogs No 81.8 83.1 80.9
Yes 18.2 16.9 19.1
Children (17 and
under)
No 80.4 84.2 77.4
Yes 19.6 15.2 22.6
Region
Europe 76.2 30.2 69.8
USA and Canada
20.8 80.6 19.4
AUS and NZ 3 42.2 57.8
Area
City centre 9.2 15.4 4.8
Urban 20.1 24 17.4
Suburban 41.9 38.9 44
Village 16.9 11.5 20.7
Rural 11.9 10.2 13.2
Dwelling Type
Flat/studio/apartm
ent 20.6 37.5 8.8
Terrace/town/row
house 18.1 12.9 21.8
Semi-detached 27.8 17.2 35.1
Detached 27 26.2 27.5
Bungalow/cottage
5.9 5.2 6.4
Other 0.7 0.9 0.5
The 5129 cats answered for were relatively evenly split between sex, with 50.6% being
female. The majority were neutered (96.8%), microchipped (79.0%), up to date with
relevant vaccinations by the owner’s definitions (75.4%), not declawed (97.9%), and had
no health problems (83.4%). A full breakdown of cat demographics and the split between
indoor-only and indoor-outdoor cats can be seen in Table 2.
Animals 2021, 11, 253 8 of 26
Table 2. Cat demographics and their management practices as reported by 5129 owners. The percentages for all cats can
be seen, alongside a breakdown of those with an indoor-only lifestyle (n = 2104) and an indoor-outdoor lifestyle (n = 3025).
Cat
Demographics
Categories Proportion of Total
Population (%) (n = 5129)
Proportion of Indoor-
Only Population (%)
(n = 2104)
Proportion of Indoor-Outdoor
Population (%) (n = 3025)
Cat age
Kitten
(0–6 months
old)
1 1.7 0.4
Junior
(7 months–
2
years old)
26 20.2 12.6
Adult
(3–6 years
old)
33.1 43.3 43.3
Mature
(7–10 years
old)
21.1 15.4 17.4
Senior
(11+ years
old)
18.3 19 25.8
Unsure 0.5 0.4 0.5
Cat sex
Female 50.6 51.9 49.6
Male 49.3 48 50.2
Unsure 0.1 0 0.2
Health
problems
Yes 16.6 19.3 14.7
No 83.4 80.7 85.3
Pedigree
Yes 11.2 16 7.9
No 82.3 76.5 86.4
Unsure 6.5 7.6 5.8
Neutered
Yes 96.8 95 98
No 2.8 4.8 1.4
Unsure 0.4 0.2 0.6
Microchipped
Yes 79 71.4 84.3
No 19.8 27.4 14.5
Unsure
1.2
1.2
1.2
Vaccinated
Yes 75.4 75.2 75.5
No 20.8 21 20.7
Unsure
3.9
3.9
3.9
Declawed
Yes 2.1 4.2 0.1
No
97.9
95.7
99.4
Unsure
0
0.1
0
3.2. Variables as Predictors of Lifestyle (Odds Ratios)
Of the 12 major variables tested across the three described models, 10 were found to
be significantly associated with cat lifestyle. Full details can be found in Tables 3–5, whilst
a summary is provided below.
Variables with greater odds of cats having an indoor-only lifestyle were owners who
were 26–35 years old (p = 0.001, odds ratio (OR) 0.765) when compared to those 36–45
years old, cats in multi-cat households (p < 0.001, OR 0.768) compared to single cat
households, junior cats (p < 0.001, OR 0.656) when compared to adult cats, pedigree cats
Animals 2021, 11, 253 9 of 26
(p < 0.001, OR 0.441) or those whom owners were unsure of their pedigree status (p = 0.004,
OR 0.707) compared to non-pedigree cats, cats with health issues (p < 0.001, OR 0.596)
compared to cats with no health issues, living in city centres (p < 0.001, OR 0.442) or urban
areas (p = 0.001, OR 0.730) when compared to suburban areas, and living in the USA and
Canada (p < 0.001, OR 0.093) or Australia and NZ (p = 0.001, OR 0.510) when compared to
living in Europe.
Table 3. Model 1, owner demographics: Results of 4909 owner household variables tested through
binary logistic regression for their association with cat lifestyle. Owners with increased odds of
providing outdoor access are indicated by an odds ratio (OR) greater than one, whilst an OR lower
than one indicates owners with increased odds of keeping cats as indoor-only.
Owner Household Variables Sub-Group
Probability OR 95% C
onfidence
Interval (CI)
Owner gender
Female
Reference
Male
0.231
0.886
0.727–1.080
Owner Age
18–25
0.943
0.993
0.815–1.209
26–35
0.001
0.765
0.651–0.898
36–45
Reference
46–55
0.006
1.281
1.073–1.529
56+
<0.001
1.499
1.224–1.836
Children
No
Reference
Yes
<0.001
1.707
1.461–1.995
Other cats
No
Reference
Yes
<0.001
0.768
0.683—0.865
Dog
No
Reference
Yes
0.078
1.149
0.984–1.340
Table 4. Model 2, cat demographics: Results of 4909 cat variables tested through binary logistic
regression for their association with cat lifestyle. Cat features that increase their odds of being
provided outdoor access are indicated by an OR greater than one, whilst an OR lower than one
indicates cat features that increase odds of being kept as indoor-only.
Cat Variables Sub-Group Probability OR 95% CI
Sex Female Reference
Male 0.016 1.155 1.028–.298
Age
Junior <0.001 0.656 0.565–0.762
Adult Reference
Mature 0.047 1.179 1.002–1.386
Senior <0.001 1.445 1.211–1.724
Pedigree
No Reference
Unsure 0.004 0.707 0.559–0.894
Yes <0.001 0.441 0.367–0.529
Health Issues No Reference
Yes <0.001 0.596 0.507—0.700
Variables found to have greater odds of being associated with an indoor-outdoor
lifestyle were owners being 46–55 years old (p = 0.006, OR 1.281) or 56+ years old (p < 0.001,
OR 1.499) when compared to those 36–45 years old, owners with children (17 years old or
under), living at home (p < 0.001, OR 1.707) when compared to those without, cats being
male (p = 0.016, OR 1.155) compared to being female, and cats being mature (p = 0.047, OR
1.179) or senior (p < 0.001, OR 1.445) when compared to adult cats.
Animals 2021, 11, 253 10 of 26
Table 5. Model 3, geographical features: Results of 4909 area variables tested through binary
logistic regression for their association with cat lifestyle. Geographical variables where owners
have increased odds of providing outdoor access are indicated by an OR greater than one, whilst
an OR lower than one indicates geographical variables where owners have increased odds of
keeping cats as indoor-only.
Area Variables Sub-Group Probability
OR 95% CI
Area
City centre <0.001 0.442 0.341–0.574
Urban 0.001 0.730 0.607–0.877
Suburban Reference
Village 0.796 0.974 0.801–1.186
Rural 0.223 1.154 0.916–1.454
House Type
Flat/studio/apartment <0.001 0.199 0.162–0.245
Terrace/town/row house
0.165 0.868 0.711–1.060
Semi-detached Reference
Detached 0.385 1.093 0.894–1.336
Bungalow/cottage 0.637 1.079 0.787–1.478
Region
Europe Reference
USA and Canada <0.001 0.093 0.076–0.114
Australia and NZ 0.001 0.510 0.349–0.746
3.3. Lifestyle Choice Rationale
3.3.1. Indoor-Only Owners
Of owners of indoor-only cats, 73.1% (1538/2104) indicated the lifestyle was their
preference, 18.7% (393/2104) indicated they did not have the option to provide their cat
with outdoor access, and 8.2% (173/2104) reported their cat chose not to go out even when
given the choice. As seen in Table 6, a total of 85% (1133/1333) of the major reasons given
for choosing an indoor-only lifestyle pertained to cat safety, not inclusive of additional
reasons provided for the ‘other’ category.
Table 6. The percentages of indoor-only cat owners (n = 1454) reporting different influence strength of factors on their
decision to give their cats an indoor-only lifestyle and the major reasons for choosing an indoor-only lifestyle globally (n
= 1333), then broken down by region.
Factors
Strength of Influence on Decision of Indoor-Only
Cat Owners (n = 1454) (%)
Major Reason Lifestyle Was Chosen by
Indoor-Only Owners (%)
None Weak Some Moderate Strong Global
(n = 1333)
USA &
Can.
(n = 634)
Europe
(n = 645)
AUS & NZ
(n = 54)
Prevent
hunting 41.5 18 14.7 9.1 16.8 3.8 4.1 1.4 29.6
Protect from
people 11.6 7.4 14.8 17.4 48.8 13.4 9.3 18.1 5.6
Protect from
traffic 1.3 1.2 3.8 7 86.7 58.7 51.6 67.1 40.7
Protect from
other cats 12.9 12.4 18.5 19.3 37 2.9 3.6 2.5 0
Protect from
wildlife 19.9 13.4 13 13.9 39.8 10 19.9 0.5 7.4
Cat has health
issues 79 6 4.6 3.1 7.3 2.6 1.9 3.3 1.9
Other - - - - - 8.6 9.6 7.1 14.8
Animals 2021, 11, 253 11 of 26
Protection from traffic was the largest influencing factor for owners across all three
regions. It was cited as the major reason for choosing an indoor-only lifestyle by most
indoor-only owners at 58.7% (782/1333), and 98.7% (1435/1454) of indoor-only owners
were influenced by traffic to some extent when making their decision, with 86.7%
(1261/1454) saying traffic strong factor in their decision. The second major reason for
indoor-only owners choosing this lifestyle varied between regions. Owners in Europe
cited it to be protection from people (18.1%, 117/645), the USA and Canada cited
protection from wildlife (19.9%, 126/634), and owners in Australia and New Zealand cited
it was to prevent cats hunting (29.6%, 16/54).
Of indoor-only owners, 71.5% (328/459) said they had not considered the alternative
of an indoor-outdoor lifestyle. Of indoor-only owners who did consider the alternative
lifestyle, 35.3% (46/131) cited the major reason they would change would be the potential
benefits to mental health. Overall, 96.1% (126/131) of indoor-only owners considering an
indoor-outdoor lifestyle considered potential mental health benefits of outdoor access in
some capacity, with 57.3% (75/131) of owners considering this strongly. More details can
be found in Table 7.
3.3.2. Indoor-Outdoor Owners
For indoor-outdoor owners, the benefit of outdoor access to mental health was the
major cited reason for allowing cats outdoor access at 38% (226/595). The second most
cited reason was that the cat indicates they want to go outside at 32.9% (196/595). A global
breakdown for indoor-outdoor owners is not provided as it is for indoor-only owners, as
although part 2 of the survey was distributed to owners in all regions, all respondents
resided in Europe.
Of indoor-outdoor owners, 70.8% (421/595) said they had not considered the
alternative of an indoor-only lifestyle. Of those who did, traffic was again considered a
risk. Of indoor-outdoor cat owners who contemplated an indoor-only lifestyle, 96.6%
(168/174) considered traffic, with 74.1% (129/174) stating this was a strong consideration.
Protection from traffic was the most cited reason owners would switch to an indoor-only
lifestyle at 45.8% (80/174). More details on owners who considered an indoor-only lifestyle
can be found in Table 8.
Animals 2021, 11, 253 12 of 26
Table 7. Percentages of indoor-outdoor cat owners (n = 595) reporting different influence strength of factors considered
during their decision to choose their cats’ lifestyle, with their major influencing reason. Percentages of consideration given
by indoor-only owners who considered and an indoor-outdoor lifestyle for their cat (n = 131) and the percentage of indoor-
only cat owners (n = 459) who gave different reasons when asked for the major factor that would cause them to change
their cat to an indoor-outdoor lifestyle.
Factors
Strength of Influence on Decision
by Indoor-Outdoor Cat Owners (n =
595) (%)
Major
Reason
Lifestyle
Was Chosen
(n = 594) (%)
Strength of Consideration by Indoor-
only Cat Owners Who Considered an
Indoor-Outdoor Lifestyle (n = 131) (%)
Major Reason
Indoor-Only
Owners Would
Switch (n =
459) (%)
None
Weak
Some
Modera
te Strong
None
Weak
Some
Moderat
e Strong
Mental
health 1.7 1.2 19.5 6.9 70.8 38 3.1 3.1 16.8 19.8 57.3 35.3
Physical
health 1.3 2.7 19.7 7.7 68.6 18 3.8 1.5 16.8 26.7 51.1 16.1
Toilets
outside
23.9 12.6 14 17.3 32.3 5.4 42 16 14.5 10.7 16.8 5
Pest
control 66.9 17.3 3.2 6.1 6.6 0.5 72.5 9.9 10.7 4.6 2.3 2.6
Cat
wants
outdoor
access
5.6 3.7 13.5 8.6 68.7 32.9 19.1 13.7 22.9 18.3 26 24.4
Other
-
-
-
-
-
5.2
85.5
1.5
3.1
3.1
6.9
16.6
Table 8. Indoor-outdoor owners who considered an indoor-only lifestyle for their cat (n = 174) and the reported level of
consideration given to different factors when making their decision and the percentage of indoor-outdoor cat owners (n =
593) who gave different reasons when asked for major factors that would cause them to change their cat to an indoor-only
lifestyle would be.
Factors
Strength of Consideration by Indoor-
Outdoor Cat Owners Who
Considered an Indoor-Only Lifestyle (n = 174) (%)
Major Reason Indoor-Outdoor
Owners Would Switch Lifestyle (n =
593) (%)
None
Weak
Some
Moderate
Strong
Prevent
hunting 22.4 25.3 18.4 15.5 18.4 5.4
Protect from
people 11.5 10.3 19.5 19 39.7 6.9
Protect from
traffic 3.4 2.3 5.7 14.4 74.1 45.8
Protect from
other cats 14.9 19.5 25.3 28.2 12.1 2.7
Protect from
wildlife 32.2 28.7 19.5 10.3 9.2 0.5
Cat has
health issues
75.3 8 6.3 2.3 8 34.9
Other 82.2 1.1 5.2 4.0 6.9 3.9
3.4. Thematic Analysis of Responses
3.4.1. Rationales of Indoor-Only Cat Owners
In addition to the reasons provided within the survey, as detailed in Tables 6 and 7,
six additional themes were identified from open-text responses. These are as follows:
protection from traffic; protection from people; protection from other animals (including
Animals 2021, 11, 253 13 of 26
wildlife* and other cats); cat has health issues; to protect wildlife; protection from illness*;
to prevent getting lost*; acquisition requirement/recommendation*; personality
unsuitable*; pedigree cat*; cat has no previous outdoor experience*. Themes without an
asterisk were included within the initial survey, whilst those marked with an asterisk (*)
were identified from open-text responses. Table 9 highlights example quotes from owners
used to create these themes.
Table 9. Example quotes from owners used to create the 11 indoor-only rationale themes.
Theme
Example Comments
1) Protection from traffic
‘Cats live near a busy road [...] afraid they get killed so keep indoors’; ‘Live on [a] main
road and [my] previous cat got killed on [the] road’; ‘I would consider an indoor-
outdoor
lifestyle if we had a large garden . . . and we lived away from busy roads’
2) Protection from people
‘Previously had cat injured by [a] neighbour’; ‘
I was advised dog fighting is prevalent in
my area and cats are stolen as bait’; ‘She is a little blue-eyed cheetah and I worry she
would get stolen’
3) Protection from other
animals
‘We have hawks that live in a large tree in our yard and have seen a coyote in our yard’;
‘She gets bullied by other cats’; ‘
Feral cat colony outside and don’t want him exposed to
disease’; ‘Next door neighbour’s Rottweiler killed a cat that went into their garden’
4) Cat has health issues
‘Cat is deaf, so cannot safely go outside’; ‘Management of IBD’; ‘
She has had a mammary
carcinoma and requires regular medication each day’; ‘Cat is FIV+ and needs to be kept
inside for his own safety and that of other cats’
5) To protect wildlife ‘Domestic cats are a severe threat to birds’;
‘Impact of domestic and feral cats on bird and reptile populations’
6) Protection from illness (*)
‘To prevent health issues often
associated with outdoor animals, such as fleas, ticks, FIV,
FIP, etc.’; ‘Fleas and ticks live outside. I do not want them in the house!’; ‘Outdoor
exposure requires more aggressive flea/tick/other parasite treatment’; ‘Cat also eats
outdoor toxic plants’
7) To prevent getting lost (*)
‘Afraid she’d not find her way back’; ‘She was lost from her previous owners’ house (a
few streets away!) for 3 years’; ‘Cat runs away to [their] previous house if let out (even
after several years)’
8) Acquisition
requirement/recommendati
on (*)
‘Medical lab cat until 7.5 years old . . .
advised to keep indoor as would have no instinct
for dangers’; ‘Signed agreement with breeder’; ‘Adoption agency contract specifies
indoor-only’
9) Personality unsuitable (*)
‘She’s also very skittish and I worry about her around traffic’; ‘He is very nervous and
easily stressed’; ‘Our cat’s curious but too timid to stay outside for long’; ‘Too timid . . .
Shows no interest either’
10) Pedigree cat (*)
‘Bengals seem notoriously “stupid” when it comes to keeping themselves safe if
permitted free reign’; ‘Breed—Devon Rex—specifically bred as indoor cats’; ‘
My cat is a
breeding queen’
11) Cat has no previous
outdoor experience (*)
‘No outdoor experience when I got him. I don’t think he will have the necessary
experience to keep safe’.
Theme 1, Protection from traffic: Protection from traffic was the most common
consideration influencing owners to keep cats indoors. Primarily, owners focussed on the
risk of injury or death. Some owners indicated this fear was due to prior experience.
Traffic concerns appeared so strong that an absence of traffic may be enough for some
owners to change to an indoor-outdoor lifestyle.
Theme 2, Protection from people: Owners were concerned that people may cause
intentional harm to their cat. Comments referenced local incidents or specific neighbours
who had displayed such behaviours previously. Theft was an additional concern for
pedigree and non-pedigree owners, but for different reasons. Owners of pedigree animals
Animals 2021, 11, 253 14 of 26
were concerned their animal would be targeted due to their unique appearance and resale
or breeding value. Owners of non-pedigree cats mentioned concerns over their cat being
taken as bait for dogfighting.
Theme 3, Protection from other animals: Concerns regarding interactions with other
animals could be divided into those pertaining to cats (both owned and feral), local
wildlife *, and dogs *. Encounters with other cats were viewed as dangerous due to
fighting or disease transmission. Fighting was deemed to have detrimental physical and
mental implications. It was of specific concern for those with timid cats who wanted to
avoid their cat being ‘bullied’, or of owners with older cats who feared their animal would
be unable to defend themselves. Owners with local feral colonies nearby were
additionally concerned about these cats being higher risk disease vectors. More on the
concerns of disease transmission is discussed in theme 6. With regards to wildlife, owners
feared their cat may become a victim of predation and listed large mammals or birds as
potential predators. Snakes were also mentioned specifically, alongside their potential to
injure or kill cats and previous bad experiences. Comments pertaining to the potential
dangers of dogs predominantly focussed on owned dogs that may attack cats. In some
instances, these dogs were known to the owner and were deemed a particular risk.
Theme 4, Cat has health issues: Owners felt specific medical issues made it more
dangerous for their cat to be outside. FIV was often mentioned explicitly. Some owners
gave no further explanation other than to say their cat was FIV+, whilst others detailed
their concern for the health of their animal, disease transmission to other cats, or both.
Owners were also concerned outdoor access would mean being unable to control medical
issues due to being unable to monitor what the cat was ingesting or being unable to give
medication when required.
Theme 5, To protect wildlife: Owners viewed an indoor-only lifestyle as an easy way
to prevent hunting. This was typically to prevent damage to local bird populations,
although some comments additionally mentioned reptiles or small mammals.
Theme 6, Protection from illness (*): Several illnesses were mentioned as potential
threats, with many of them such as flu, FIV, or FeLV considered infectious. Owners of cats
with ongoing medical conditions had specific concerns about their cats contracting further
illness (as discussed in theme 4). Owners highlighted concerns over parasites such as fleas,
ticks, or worms, however, in many instances, the focus was not on the welfare of the cat,
but rather the owner’s discomfort. Owners felt parasites were dirty or unpleasant and
something that should not be brought into the home. Owners also acknowledged the
inconvenience and expense of the requirement to upkeep preventative treatment of
parasites for cats with outdoor access. Additionally, owners highlighted concerns about
cats consuming dangerous plants they would not encounter indoors or encountering
poisonous substances (e.g., anti-freeze or pesticides) neighbours may use and leave in
their gardens.
Theme 7, Prevent getting lost (*): Owners indicated that their cats were kept indoors
to prevent them from getting lost. It was not typically cited if this concern was for their
cat’s welfare or their own, or if they had attempted to allow their cat outdoors. Some
owners suggested they had let their cat out, and the cat returned to a previous home in
which they lived. A few owners alternatively used the phrase ‘run-away’, suggesting they
feel their cat may intentionally not return if given the opportunity.
Theme 8, Acquisition requirement/recommendation (*): The opinions of other people
were often taken into consideration, particularly those from the place owners had
acquired their cat. Adoption centres were frequently cited as influencing owner choice of
lifestyle, with some rescue organisations recommending indoor-only lifestyles for specific
cats in their care based on their history and temperament. Other rescue organisations
appeared to have a blanket policy on all cats being kept indoors. Breeders of pedigree
animals also frequently required cats to be indoor-only. Whilst some owners alluded to
these being recommendations, in some instances, owners reported both breeders and
rescue shelters requiring them to sign a contract committing to keeping their cat indoors.
Animals 2021, 11, 253 15 of 26
Theme 9, Unsuitable personality (*): Some owners felt their cat’s temperament made
them unsuitable to go outdoors. Some felt their cat’s temperament may put them at a
greater risk of harm outdoors, such as skittish cats or over-friendly cats. Other owners
seemed to feel that the experience of being outdoors would be detrimental to the cat’s
mental welfare, especially owners of cats who intensely disliked other cats or cats deemed
to be timid/shy/anxious. Some owners seemed to indicate they had attempted some form
of outdoor access off which they had based their decision, whilst other owners made the
decision without trying any form of outdoor access beforehand.
Theme 10, Pedigree cat (*): In addition to the concerns over theft, as presented in
theme 2, pedigree cats were often kept indoors as their temperaments were deemed
unsuitable to have outdoor access. Numerous breeds were cited as being incapable of
looking after themselves outdoors. Other owners believed their cat had no desire or need
to go outdoors and has been bred to be indoor-only. A small number of owners felt their
breed was unsuitable to go outdoors due to physical attributes, e.g., hairless breeds being
unable to keep warm. Less often, owners were using their cats for breeding and aimed to
prevent unwanted pregnancy.
Theme 11, No previous outdoor experience (*): Owners of cats who had previously
been kept as indoor-only did not want to change that lifestyle to indoor-outdoor. These
cats were typically not obtained by their owners when they were kittens. When acquired
as adults, owners felt their cats lacked the experience needed to stay safe whilst roaming
and so were better off staying indoors.
3.4.2. Rationales of Indoor-Outdoor Cat Owners
For indoor-outdoor cat owners, in addition to the five themes provided within the
survey questions, five further themes were identified from open-text responses. These
were ‘beneficial to mental health’, ‘beneficial to physical health’, ‘cat indicates they want
to go outside’, ‘cat toilets outside’, ‘pest control’, ‘enrichment*’, ‘previous outdoor access*’,
‘social opportunity*’, ‘safe outdoor space*’, ‘multi-cat household*’, and ‘natural*’. Table
10 highlights example quotes from owners used to create these themes.
Animals 2021, 11, 253 16 of 26
Table 10. Example quotes from owners used to create the 10 indoor-outdoor rationale themes.
Theme Example Comments
12) Beneficial to
mental health
‘Would never have an indoor- only cat. Had one some years ago when I lived in a flat and he
was a monster. Destroyed furniture, bedding, carpets,
and clothing. When I moved to a house,
he started to go outside and he calmed down completely’.
13) Beneficial to
physical health
‘Allows them to . . . control their weight through increased exercise’; ‘My cat was kept in for 12
months but had IB symptoms i.e.,
diarrhoea. I think she was very stressed and unhappy as an
indoor cat’.
14) Cat indicates they
want to go outside
‘I never force my cats either indoor or outdoor but let them make their own decision. This
means they have their own choice which helps their mental wellbeing’; ‘I don’
t want my cats to
be captive—I want them to be free to choose to stay with us and to live as they choose’.
15) Cat toilets outside
‘JLD will not toilet inside and becomes distressed if he has no outdoor access’; ‘I hate litter
trays!’
16) Pest control ‘I rely on their hunting to control rats and mice that would otherwise be attracted to the
farmhouse and the chicken pens’.
17) Enrichment (*)
‘Her world is so much bigger by having that access to the outdoors’; ‘
Lots of interaction outside
that I cannot provide indoors’; ‘
My cat has always enjoyed sitting on the grass sniffing the fresh
air’; ‘I hate the fact that one of my cats hunts . . . However, they both find it distressing to be
locked in’
18) Previous outdoor
access (*)
‘They were five when I got them and they had been used to going out’; ‘
Most of my eight cats
have been stray toms, a couple are still semi-feral,
one of which gets very aggressive when kept
in all the time’.
19) Social opportunity
(*)
‘I feel it’s unfair to leave my cat at home alone all day, when he could be outside and visiting
the neighbours he really likes!’; ‘We enjoy having an active cat who
engages with other cats in
the neighbourhood’.
20) Safe outdoor space
(*)
‘ I also do not live near a busy road so am happier letting them out.’; ‘
We felt it was best for
the cats, so bought appropriate properties’.
21) Multi-cat
household (*)
‘I li
ve in a small house with four cats. A large garden gives the room to have a break from each
other’; ‘It seemed unfair to have one rule for one cat and one rule for another’.
22) Natural (*) ‘Allows natural behaviour for my cat’; ‘I feel that although humans, over the centuries, have
domesticated cats, they still very much have a natural desire, interest in . . . the outdoors’.
Theme 12, Beneficial to mental health: Alongside the thinking that outdoor access
was beneficial to mental health, it was felt that confining a cat to the indoors could have
negative impacts. Some owners detailed having experienced this with their current or
previous cat. The impact of being confined indoors on the cat’s mental health was often
described as causing stress, depressive states, or states of (sometimes extreme) agitation.
Many owners felt that the outdoors did not just prevent negative mood states, but also
promoted positive experiences. This is discussed further in theme 17.
Theme 13, Beneficial to physical health: Owners who felt the outdoors was beneficial
to physical health recognised that the opportunity for exercise was good for weight
management. Owners also mentioned the overlap between physical and mental health.
Poor mental health and stress were cited as causing general sickness behaviours, such as
vomiting or poor coat condition. Other owners detailed how the stress caused or
exacerbated existing conditions, such as cystitis.
Theme 14, Cat’s choice: Many owners simply let their cat decide whether they
wanted outdoor access. Autonomy and choice were recognised as mentally beneficial for
cats in addition to the outdoor access itself. This was so important to some people that
they allowed outdoor access even if they would have preferred otherwise. Not giving cats
a choice was often deemed as cruel or unfair. Additionally, some owners seemed to
Animals 2021, 11, 253 17 of 26
appreciate the fact that their cat lived with them through choice because they had the
opportunity to leave yet did not take it.
Theme 15, Cat toilets outside: Mentions of toileting habits were predominantly from
the perspective of the cats who preferred to do so outside rather than using the litter tray,
or in some instances, would only toilet outside. Some owners did, however, mention they
preferred their cat to toilet outside.
Theme 16, Pest control through hunting: Whilst many owners kept cats indoors to
prevent hunting, as discussed in theme 5, some owners found this trait to have positive
utility in terms of pest control. Hunting as a form of enrichment was also identified as
beneficial and is discussed more in theme 17.
Theme 17, Enrichment (*): Owners often felt the outdoors provided good enrichment
for their cat to keep them entertained and stimulated. Some people detailed that they had
purposefully added objects into the garden to accentuate this further. Often, it was felt
that this outdoor enrichment was unique and could not be readily replicated indoors,
specifically with regards to weather. Sunshine was viewed as a positive experience for
many cats who appeared to actively enjoy spending time in it. Fresh air was mentioned
as being enjoyable from a cat’s perspective, but owners also indicated they felt it
beneficial. Cats were detailed as avoiding less favourable weather, such as rain or cold
temperatures, but this was usually a choice that the cat was free to make.
Sub-theme of Theme 17: Opportunity to hunt—The opportunity to hunt was often
viewed as a natural and instinctive behaviour which could readily be provided for
outdoors should the cat wish. Owners did not necessarily encourage this behaviour but
accepted it as beneficial to the cat’s wellbeing for them to have the opportunity. Some
owners had aversions to hunting but appeared to feel their cats’ wellbeing outweighed
this.
Theme 18, Previous outdoor access (*): Many owners obtained adult cats with
previous outdoor experience and so felt they did not want to deprive them of the outdoor
access they had been used to. Cats who were strays, feral, or farm cats were specifically
mentioned as these cats were used to spending large portions of their time outdoors. Some
owners alluded to keeping these cats indoors temporarily to detrimental effect.
Theme 19, Social opportunity (*): The opportunity for social interaction with people
and conspecifics outside of the immediate household was recognised as beneficial. Cats
were detailed as enjoying interacting with neighbours, and owners appreciated how this
brings happiness to the neighbours in turn. It was also felt to be unfair to not allow cats to
have the opportunity to socialise when the owners were not at home. Cats were also
reported to spend time interacting positively with other cats in the neighbourhood.
Theme 20, Safe outdoor space (*): The dangers cited by the owners of indoor-only
cats, such as traffic or wildlife, were also acknowledged by the owners of indoor-outdoor
cats, yet many owners felt the area they lived in was safe enough to mitigate the risks of
injury or death sufficiently. For those who felt their area was safe enough to allow their
cat outside, it was unclear what they would do should they have to move, with some
owners acknowledging they might reconsider providing outdoor access in such
circumstances. However, some owners felt the outdoors was of such benefit to their cat
that they ensured their property was safe enough to allow outdoor access when they were
looking for a home.
Theme 21, Multi-cat household (*): The management of cats within a multi-cat
household was deemed to be easier by allowing outdoor access. Many cats lived in multi-
cat households where the lifestyle of previously obtained cats determined the focal cat’s
subsequent lifestyle. In instances where the focal cat had joined a household which
already contained cats with outdoor access, owners felt that unequal treatment was unfair
and that the cats themselves may feel so too. Additionally, the extra space provided
outdoors was cited to be beneficial for allowing cohabiting cats to have time away from
one another. It was felt that outdoor space reduced the amount of physical conflict and
aggression between cats of the same household.
Animals 2021, 11, 253 18 of 26
Theme 22, Naturalness (*): The term ‘natural’ was frequently used in explaining why
outdoor access had been chosen. This was seen to encompass many of the previously
discussed themes around mental and physical benefits, enrichment such as climbing and
exploring, as well as the need to hunt. The unique domestication of cats and fluidity of
individual cats’ socialisation was also mentioned to highlight the ‘nature’ of cats and as a
reason to allow outdoor access.
4. Discussion
Overall, 41% of cats within this study were indoor-only. Differences were seen
among the three global regions—at 30.2% in Europe, 80.6% in the USA and Canada, and
42.2% in AUS and NZ. Region was found to have a significant impact on lifestyle, with
cats comparatively much less likely to be indoor-outdoor in the USA and Canada (OR
0.093) and AUS and NZ (OR 0.510) than in Europe. The proportions of cats kept indoors
in Europe in this study were not too dissimilar to others. In the UK, 26.1% of cats were
indoor-only [8]; in Denmark, 16.8% of cats were indoor-only; [5] and in France, 34% were
indoor-only [45]. For the USA and Canada, results in this study showed a higher
percentage of indoor-only cats compared to a reported 63% [46] and 60% [31] for the USA,
or 56% in Canada [47]. For AUS and NZ, it has been reported that 44% [48] or 46.5% [7] of
cats in Australia are indoor-only, whilst in Melbourne specifically, it was reported to be
23% [49]. In New Zealand, it has been reported that 10.7% of cats were indoor-only at all
times [50], whilst 26% were indoors during the night [51]. Although our study broadly
concurs with others there are notable differences in proportions of indoor cats within
specific regions. It is likely the intra-region variation amongst studies arises due to the
grouping of regions in this study, where previous studies typically focus on a single
country or state within a country.
4.1. Safety
Safety, in some regards, was the primary motivating factor for keeping cats indoors
across all three regions (USA and Canada, 84.3%; Europe, 88.2%; and Australia and New
Zealand, 53.7%). The motivation for owners wanting to keep their cat safe seemed to be
both a concern for the welfare of their cat and protecting themselves from the emotional
harm of losing their cat to fatal incidents. Safety concerns have been acknowledged in
other studies. A UK study found 63% of UK owners with indoor cats felt it was unsafe for
their cat to be outdoors [52]. An Australian study found 75.4% of cat owners felt keeping
cats contained was important to protect them from injury [33]. Whilst a New Zealand
study found 45% of people who kept their cats indoors at night did so due to safety [53].
These differences in numbers may arise due to variations in the owner populations being
studied. Both the Australian and New Zealand studies included owners who allow their
cats to roam in some capacity and such owners are perhaps less likely to be concerned
over safety than the owners of indoor-only cats.
4.2. Road-Traffic Accidents
The greatest influencing factor for an indoor-only lifestyle, which was consistent
across global regions, was protection from RTAs. Concerns over RTAs have been
indicated elsewhere. Of UK indoor-only cat owners who deemed the outdoors to be
unsafe, 83% felt this way due to traffic concerns [52]. However, incidences of RTAs, in the
UK at least, appear relatively low. Whilst fatal RTAs are difficult to quantify because they
are typically not reported, and record keeping by local authorities and veterinary practices
vary, several UK studies have aimed to estimate these figures. One study found only 4.2%
of cats registered to VetCompass and presented to the emergency, out-of-hours practices
in the UK between January 2012 and February 2014 had been involved in an RTA [54]. In
Cambridgeshire, UK, an estimated 12% of cats had survived an RTA [22]. With these
veterinary studies, it must be considered that RTA numbers are likely to be higher because
Animals 2021, 11, 253 19 of 26
deceased animals are not likely to be presented to practices. A longitudinal cohort study
of 1264 UK cats negated this bias of not reporting fatal incidents and found that, within
the first year of life, 3.9% of cats were found to be involved in RTAs, with 71.4% of these
being fatal [55]. These UK-based figures are unlikely to be applicable to other countries,
or even regions within the UK different from the studied area, due to differing densities
of free-roaming cats, varying levels of traffic, or traffic speed. Consequently, more
research into the RTA rates in different regions is required to help owners better
understand the risks of providing an indoor-outdoor lifestyle.
Despite these overall low incidence rates, many previous studies have identified
RTAs to be a major, or leading, cause of accidental death for younger pet cats specifically
[21,22,56,57]. The increased risk for younger cats is likely due to a combination of factors
such as a lack of experience and higher energy levels, resulting in a greater propensity to
roam [57]. It has also been found that older cats are less likely to engage in risk-taking
behaviours, including crossing roads [58]. Results from this study suggest owners may
recognise that potentially risky behaviours may be more common in junior cats because
this age group had greater odds of being kept as indoor-only cats compared to adult cats.
Given the energy levels of, and stimulation required for younger cats, it is therefore
particularly important that sufficient enrichment is provided within the home. In contrast,
senior cats were the most likely age group to be provided with outdoor access. In free-text
responses, older cats were detailed as only utilising garden spaces rather than roaming
freely. For example, ‘Eldest [cat] is 11 years [old] and goes out unsupervised twice a day
but remains in the garden’ and ‘Now he [cat] is older he never leaves my garden’. For
older cats with previous experience outdoors particularly, it is promising that the
recognition of this lower-risk outdoor behaviour may alleviate owner safety concerns over
RTAs and make them more amenable to providing outdoor access.
4.3. Urbanisation
It is known that the number of indoor-only cats is rising, and it has been theorised
that this may, in part, be due to increasing urbanisation. This theory is supported by the
findings of this study, which indicated city or urban-dwelling owners and those living in
flats or apartments are significantly more likely to have an indoor-only cat. Alongside
owners not having outdoor space available, increased traffic in these urbanised areas is
likely to be a contributing factor to the number of indoor-only cats, given the high level of
safety concerns reported. Despite RTA fears in urban areas, and some indoor-outdoor
owners only allowing outdoor access for their cat because they felt they lived in an
appropriately quiet area with an absence of traffic (theme 20), the concerns over increased
RTAs within built-up areas may be unfounded. One study found no significant
association between area (urban/rural) and higher RTA mortality [57]. Whilst a second
did find differences in RTA prevalence between areas, it was cats living in rural areas that
seemed to be at increased risk when compared to cats within urban environments [55].
More detailed insights as to how, where, or when RTAs occur, including the time of day,
could mean that owners in lower-risk areas are able to make more on-balance decisions,
comparing the risks of outdoor access and any individual needs of their cat.
4.4. Variation between Regions
The second most cited reason for keeping cats indoor-only varied throughout the
three regions. In the USA and Canada, it was for protection from wildlife (19.9%). In
Europe, it was protection from people (18.1%). In Australia and New Zealand, it was to
prevent cats from hunting (29.6%). This difference between regions could be due to
variation in geography, urbanisation, and local wildlife. Respondents from Europe were
predominantly UK-based (80.3%). The UK is densely populated and highly urbanised
when compared to many regions within the USA, Canada, Australia, and New Zealand,
which all have large, sparsely populated areas. Therefore, it is reasonable that owners in
Europe have urban-centric concerns, whilst in the USA, Canada, Australia, and New
Animals 2021, 11, 253 20 of 26
Zealand, concerns are typically nature-orientated. The differences in concern for wildlife
in the USA, Canada, Australia, and New Zealand may be explained by the types of
wildlife found between the regions, as well as whether predators are endemic or not.
In the USA and Canada, large predators are commonplace. The presence of larger
predators such as coyotes, eagles, or bears may mean prey species have adapted better to
avoid predation, dampening the effects of depredation by cats and meaning cats are at
risk of predation themselves. In Australia and New Zealand, there are no large predators,
although poisonous insects or snakes may still pose a risk to cats. The absence of predators
makes local wildlife particularly susceptible to cat depredation, and this ecological niche
has made it easy for cats to reproduce and survive. Consequently, in Australia and New
Zealand, there are large feral populations which have been estimated as being more
numerous than owned cat populations [59], and cats are classed as an invasive species
[41]. Many studies in Australia and New Zealand have investigated the attitudes of both
cat owners and non-owners towards wildlife depredation and have repeatedly found it is
a concern for both [33,60,61]. The management of cats has previously been found to reflect
this concern, with many owners in these regions restricting outdoor access entirely or at
certain times of the day [33,51], echoing the findings of this study.
4.5. Pedigree
Pedigree cats were more likely to be kept indoors than non-pedigree cats. Pedigree
animals were described as ‘stupid’, ‘dopey’, or lacking ‘common sense’, and owners stated
they were ‘not designed for the outdoors’ or had been bred to be indoor-only. Despite
these concerns, the authors of this paper find no evidence to suggest different breeds may
be suited to an indoor-only or indoor-outdoor lifestyle. It is possible that specific
conformations could limit the ability of some pedigree breeds to survive outdoors. For
example, brachycephalic breeds, such as Persians or Exotics, may suffer from respiratory
issues [61] and struggle to eat or chew due to shortened muzzle lengths and dental
abnormalities [62], which could impair activity levels and hunting behaviours. Hairless
breeds, such as Sphynx cats, may struggle to regulate their temperature in colder climates.
Whilst these phenotypic variations may reduce life-expectancy in unowned cats, it is not
known if they would substantially impact behaviour or welfare in cats provided with
shelter, food, and veterinary care, who also have outdoor access. Indeed, it has been
tentatively found that pedigree cats are less likely to be in RTAs than non-pedigree cats,
although sample sizes within the study were small [22]. It was posited this could be due
to more time-restricted outdoor access of pedigree cats, or that owners may spend more
close contact time with pedigree animals than non-pedigree, which mayin turn impact
their behaviour outdoors. As evidence is emerging that behaviour may vary between
breeds, in terms of social behaviour, activity levels, and temperament [63–67], it is
reasonable to assume that variation in temperament may impact suitability for different
living conditions. Further research into how breed-specific differences influence welfare
across different lifestyles is therefore warranted.
4.6. Mental Wellbeing
Both indoor-only and indoor-outdoor owners felt outdoor access was beneficial to
mental wellbeing, seemingly as it readily allows for the expression of natural behaviours.
Outdoor-specific enrichment included weather (theme 17), hunting opportunities (theme
17), toileting preferences (theme 15), and socialisation with other cats and people (theme
19). Some owners detailed how they provided additional enrichment for their cats in their
outdoor spaces. At present, no research has been conducted on the quality of outdoor
environments cats have access to and their implications for cat welfare. It is possible that
welfare differences may arise between cats with outdoor access living in rural
environments with few other domestic cats, large open areas, and abundant wildlife such
as bird and rodents compared to cats living in urban environments with dense cat
Animals 2021, 11, 253 21 of 26
populations and those with either basic or enriched outdoor spaces provided by their
owners.
4.7. Physical Health
Potential benefits to the physical health of outdoor access were strongly recognised
by both indoor-outdoor and indoor-only owners. Comments alluded to the opportunity
for exercise, and how obesity might be mitigated through outdoor access if it increases
overall activity levels in indoor-outdoor cats compared to their indoor-only counterparts.
These owner views are consistent with literature that suggests an indoor-only lifestyle is
a risk factor for feline obesity [27,68]. Obesity was recently cited by UK vets as the major
health concern for owned pet cats [68], with obese animals being more likely to suffer
from additional ailments such as arthritis or diabetes [69]. More research into the activity
levels of indoor-only versus indoor-outdoor cats, or the exercise opportunities of indoor-
only cats, could help with management strategies to ensure healthy weights and could be
a cheap, easy, and non-invasive way for owners to improve their cat’s welfare.
A growing body of literature also suggests that stress-related illnesses, such as lower
urinary tract signs, are typically more prevalent in indoor-only cats [70,71]. Although
anecdotal, some owners did appear to notice improvements in their cat’s physical health
when cats were given outdoor access after a previous restriction, and this was sometimes
linked to improvements in mental health (theme 13). It might therefore be that affording
outdoor access to cats with some pre-existing conditions could help to alleviate them.
Despite this, pre-existing health conditions were found to be a significant predictor for
cats being kept indoor-only. Whilst the frequency of specific pre-existing health
conditions was not quantified, it is possible that many cats were FIV+ and FeLV+, as
alluded to in theme 4 and 6, where responsible management has typically included the
restriction of outdoor access to these cats.
4.8. Cat Autonomy
Most indoor-outdoor owners (94.4%) took into consideration that their cat indicated
they wanted outdoor access when deciding on lifestyle. It was the major reason for
providing this lifestyle for around a third of owners. Similarly, an Australian study found
that 37% of owners who allowed their cat outdoor access at night did so for the cat’s
freedom [53]. In comparison, 80.9% of indoor-only owners who considered an indoor-
outdoor lifestyle considered if their cat indicated they wanted outdoor access. However,
only 8.2% of indoor-only cats were ultimately reported to ‘choose’ their lifestyle by not
leaving the house when able to. This leaves an overwhelming majority of 91.8% of indoor-
only cats who may otherwise opt to roam outdoors if given the opportunity.
From this small percentage of cats opting not to go outside when given the choice,
one may infer that most cats are highly motivated to access outdoor spaces if available.
Some owners did report negative behavioural differences in their cats when restricting
their outdoor access (themes 12 and 21), and indeed, undesirable behaviours are
commonly reported as being more prevalent in indoor-only cats when compared to those
with outdoor access [5, 8, 36–38]. Whilst enrichment items may provide the opportunity
for cats to express natural behaviours indoors, the observed levels of undesirable
behaviours in indoor-only cats might generally indicate the provision of suboptimal
environments. A recent systematic review identified numerous gaps in the literature with
regards to indoor-only cat welfare [72]. It also noted that some enrichment guidelines
recommended by behaviourists or charities may not be evidence-based. This dearth of
literature in the area may make it more difficult for owners to fully meet their cat’s
behavioural needs within the home.
Currently, it is not known how the prevalence of undesirable behaviours, stress-
related illnesses, or other welfare indicators vary between cats who choose to stay indoors,
and those who have the choice made for them. It may be cats without the opportunity of
choice are of an increased welfare concern. It has been posited that environmental control
Animals 2021, 11, 253 22 of 26
is beneficial for animals [73], and recent research into other domestic or captive species,
including great apes, pandas, sheep, and goats, has demonstrated the positive impact of
choice and control on welfare [74–76]. Further research into how choice and control may
impact welfare in cats with owner-controlled and time-restricted outdoor access, as
opposed to a freely accessible cat-flap, is therefore warranted.
4.9. Alternative Lifestyle
Most respondents did not consider an alternative lifestyle for their cat. This might
suggest owners have an inherent view of appropriate cat husbandry they do not deter
from. Such views are of potential concern if owners do not consider how individual
temperaments or life experiences are suited to different lifestyles. However, it may
transpire that owners did not consider an alternative lifestyle as they chose a cat deemed
suitable for the lifestyle they wanted to provide. Further study into whether owners seek
a suitable cat for their preferred lifestyle could indicate whether cats may be suffering due
to inappropriate husbandry.
In this study, there was some indication owners may select a cat suitable for their
chosen lifestyle. Some owners felt their cat’s personality was unsuitable for outdoor access
(theme 9), indicating that they were making a judgement of their cats’ temperament and
providing for them as they saw best. Other owners maintained the lifestyle their cat was
used to, whether that be indoor-only or indoor-outdoor (themes 11 and 18). Additionally,
owners indicated they were acting upon advice from veterinary professionals or rescue
centres from which the cat was acquired (theme 8), although it is not evident whether this
advice was based on temperament and lifestyle suitability or other factors such as safety
or cat depredation.
When owners reported the major reason they would change their cat’s lifestyle,
results echoed those of owners who had chosen the opposite lifestyle. For example, most
indoor-only owners chose this lifestyle to protect their cat from traffic (58.7%), and most
owners of indoor-outdoor cats reported if they were to change their cat’s lifestyle to
indoor-only, it would be due to traffic (45.8%). Conversely, the benefits of outdoor access
to mental health were acknowledged by many indoor-outdoor and indoor-only owners,
with 38% and 35.3% giving this as the major reason for the lifestyle choice, or the reason
they would change, respectively. This might suggest owners do recognise the positive and
negative factors attributed to each lifestyle, even if they have a preferred lifestyle they
adhere to.
Currently, we are unsure if there are differences between the management of indoor-
only and indoor-outdoor cats with regards to resource provision, enrichment, and social
interaction. If management varies, this could account for some of the perceived differences
in the need for cats to obtain enrichment outdoors. For example, indoor-only cat owners
who recognise the potential mental benefits of outdoor access may be more inclined to
provide additional enrichment within the home when compared to those who do not
acknowledge that outdoor access can be beneficial. Conversely, indoor-outdoor owners
may feel that outdoor access is sufficiently enriching and provide less within the home,
which could be problematic if they provide restricted outdoor access.
4.10. Limitations
As with any research, methodological limitations must be acknowledged. Online
convenience sampling is a practical way of contacting large numbers of international cat
owners; however, it may introduce sample bias. Owners chancing upon, and opting into,
a survey regarding their cat may be systematically different from owners who do not find
or engage in such surveys. This may be true for those who consent to participate in further
studies and those who did or did not respond to the second survey. Generally, owners
who did not participate may feel less strongly about the topic than owners who freely
opted to give spare time for completing the surveys. This should be remembered when
Animals 2021, 11, 253 23 of 26
contemplating the strength of consideration owners assigned to different factors that
influenced their decision making.
Additionally, it is acknowledged that this study does not present an exhaustive list
of factors which may influence owner decision making. Other influences may include, but
not limited to, previous cat ownership, place of cat acquisition, and age of cat at
acquisition, as suggested by the thematic analysis. Because this study was the first detailed
look at owner rationale for cat lifestyle, it is hoped that further studies can expand upon
the results presented in this paper.
5. Conclusions
Ten owner and cat demographic variables were significantly associated with greater
odds of cats being provided with either an indoor-only or indoor-outdoor lifestyle,
inclusive of the global region, owner age, or cats having health issues, etc. Many of these
variables offer evidence that urbanisation could be a driving factor behind the current
data trends which suggest owners globally are moving towards indoor-only lifestyles for
their cats. It was shown that owners living in city centres, urban environments, and
flats/apartments were significantly more likely to have indoor-only cats. Strong concerns
over traffic were voiced by indoor-only and indoor-outdoor cat owners, and RTAs were
a major influencing factor for owners when deciding on lifestyle. Because urbanisation is
set to continue, it is reasonable to assume that the proportion of indoor-only cats will
continue to rise.
Considering the anticipated increase in indoor-only cats, alongside current literature
suggesting indoor-only animals may exhibit more ‘undesirable’ and stress-linked sickness
behaviours than indoor-outdoor cats, research focussing on how best to improve the
behaviour and wellbeing of indoor-only cats would be beneficial. Particular attention
should be paid to subgroups of cats found to be significantly more likely to be kept indoor-
only, such as pedigree animals. Despite certain pedigree breeds being perceived as being
better adapted to an indoor-only lifestyle, there is currently a paucity of scientific evidence
in this area.
Finally, owners appeared to hold an inherent position in which they believe cats
should have an indoor-only or indoor-outdoor lifestyle, as indicated by most owners not
actively considering the alternative lifestyle. It is important for owners to recognise the
individual needs of cats with different temperaments, activity requirements, or previous
life experiences, lest the welfare of individuals suffer if not adequately provided for.
Author Contributions: Conceptualization, R.F.-W. and M.F.; Methodology, R.F.-W., M.F., S.W., and
L.F.; Formal analysis, R.F.-W.; Data curation, R.F.-W.; Writing—original draft preparation, R.F.-W.;
Writing—review and editing, R.F.-W., M.F., S.W., and L.F.; Supervision, M.F., S.W., and L.F. All
authors have read and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: The study was conducted according to the guidelines of the
Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of
Nottingham Trent University (ARE843, 11 December 2018).
Data Availability Statement: The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to data privacy and identifying
information of participants.
Conflicts of Interest: The authors declare no conflict of interest.
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