The keeping of non-domestic species as pets, companion animals or part of ornamental or specialist collections is becoming increasingly popular. Numerous species of mammals, birds, herptiles, fish and invertebrates are available in the exotic animal trade. However, it is important to carefully consider the suitability of such species for a captive environment and research the needs and requirements of these species diligently before the decision to keep them is made.
Alongside the “regular” exotic pets such as corn snakes (Pantherophis guttatus) or bearded dragons (Pogona vitticeps), more specialised wild animals that require a dangerous wild animal (DWA) licence are also kept in the UK. Estimates suggest that nearly 2,500 DWA-registered species are housed in England alone (Tovey, 2022).
What makes wild species different to domesticated ones?
Unlike domesticated breeds of dog, cat, chicken or goldfish, exotic animals are not so far removed from their original wild ancestors. Their behaviour patterns will be more aligned to a life of freedom rather than one lived in a human-created environment. As such, behavioural disturbances (such as pacing, self-damaging and displacement or redirected activities) that indicate negative welfare experiences are more common in a captive environment.
It is a greater challenge to provide sufficient and appropriate opportunities and outlets for adaptive traits and highly motivated behaviours to be performed (ie characteristics and behaviours that have evolved for a specific survival reason) when a species has not been domesticated and, therefore, has not been moulded or changed to be best suited to life around humans (Figure 1).
Even if an exotic species is captive-bred, it has not been domesticated. “Captive-bred” simply means the individuals in the pet trade have been produced from other captively housed animals rather than being sourced from the wild. These captive-bred animals are more likely to be tame and acclimatised to human care, but they are not markedly changed from their ancestors and therefore are not domesticated.
Captive-bred animals are more likely to be tame and acclimatised to human care, but they are not markedly changed from their ancestors and therefore are not domesticated
Dogs, wolves and sugar gliders: a study in captivity
The gulf between our understanding of the needs of domesticated breeds compared to exotic species kept as pets is probably best illustrated by the evolutionary history of the domestic dog (Canis lupus familiaris) and the sugar glider (Petaurus breviceps), a marsupial mammal from Australia.
Genetic research published in 2015 suggests that dogs first split away from ancestral grey wolves (Canis lupus) potentially up to 40,000 years ago (Skoglund et al., 2015), with domestication following shortly after this. This highlights the intensity and longevity of the relationship between dogs and humans. In fact, the dog is the oldest of all domesticated breeds (the next being the sheep, Ovis aries, around 8,000 to 9,000 years ago). Because of this long association, we know what to provide for a pet dog, we know how to interact with them and there is a deeper level of communication and understanding between us and our canine companions.
Our manipulation of dog reproduction has not only caused them to look completely different from wolves from the outside, but it has also changed the structure of different brain regions
Our manipulation of dog reproduction has not only caused them to look completely different from wolves from the outside, but it has also changed the structure of different brain regions (Hecht et al., 2019), which has resulted in different behavioural specialisation desired by humans.
Conversely, the sugar glider first appeared in the US exotic pet market in the 1990s (Brust, 2009). It is not domesticated, and we have had just over 30 years of experience with its husbandry care. Sugar gliders are difficult to look after properly and are often seen by specialist exotic vets because of husbandry-related pathologies (Lennox, 2007). They have a poor tolerance for pain and will often eviscerate themselves by chewing on the stitched area following surgery (Ness, 2012).
Sugar gliders are difficult to look after properly and are often seen by specialist exotic vets because of husbandry-related pathologies
Perhaps what best illustrates our challenges of providing correct sugar glider care is that many of the sugar gliders available for sale may not actually be sugar gliders but a closely related species of possums in the same Petaurus genus (Campbell et al., 2019). If we struggle to correctly identify the species that we are keeping, we have even less of a chance of providing the right environment and care needs.
Five key principles for keeping wild animals in captivity
Before considering an exotic species as a pet or companion animal, it is important to remember the following five key principles to be welfare-positive and ethical in our approaches to exotic pet care.
1) Housing needs and life-long care
- What area is required for roaming, daily movement and performance of essential natural behaviours? Can these be replicated in an enclosure?
- Can we provide the required resources easily to promote behavioural diversity and good welfare?
- Do housing needs extend to the regulation and control of heating, lighting, ventilation, humidity and other climatic parameters at different times of the day/night? Can these environmental aspects be controlled/managed?
- Is there a veterinary specialist nearby who can provide appropriate treatment and healthcare for the species in question if needed?
2) Social group and space
- Is the species naturally social or solitary? Do the social preferences of the species change with age and development?
- Can a natural sex ratio and minimum number of animals be maintained easily in a captive environment?
- Can an enclosure provide sufficient space for different/all members of the group to come together and/or remove themselves from the group as and when desired?
- How big does the species grow when mature? Can this size be easily accommodated for all individuals in a social group?
- How much space does each individual animal require to be comfortable in a social group (if applicable) or to fully engage with the environment around it, and can this amount of space be provided?
- Can an appropriate diet for each life stage of the animal be easily provided?
- Are there alternative ingredients that are readily accepted by the species if wild foodstuffs cannot be sourced?
- Has a captive diet been nutritionally analysed to ensure its suitability?
- Will captive diets (including any substitute ingredients) promote important natural feeding and foraging behaviours?
4) Source population
- Are individuals in the trade captive-bred? Is this captive population sustainable and well-managed?
- Does the breeder keep records? Can they verify the source and origin of all animals under their care?
- If the species is wild-caught, is this sustainable and conducted in an ethical way?
- Can relevant paperwork and documentation be sought and verified (eg CITES paperwork) where required according to a species’ status?
5) Behavioural needs
- Are the behavioural needs and natural time-activity budget of the species documented to evidence the appropriateness of a captive environment to behavioural outputs?
- Can all natural behaviours be performed in captivity?
- If some behaviours cannot be performed, what are the welfare implications of this? Are the welfare implications known?
- If the species is prone to abnormal repetitive behaviours (such as stereotypic pacing, self-directed behaviours or behavioural disturbances that impact health), can these be treated and rectified with changes to husbandry, use of enrichment or positive reinforcement training?
Owners (both potential and actual) should ask themselves if they have the answers to all these questions under each of the five points listed above (Figure 2). If answers cannot be found, and the owner is then ignorant of such key aspects of an exotic species’ biology, behaviour and care needs, it is best (from an animal welfare and ethical perspective) to err on the side of caution and not keep the species in the first place.