The ethics of enrichment

October 17, 2017
Barry Kipperman, DVM, DACVIM

Dr. Kipperman is a diplomate of the American College of Veterinary Internal Medicine. He has practiced in a 24-hour referral practice since 1992. Dr. Kipperman is owner of the VetCare-24 hour referral practice in Dublin, Calif. He is guest lecturer at the University of California-Davis veterinary school ethics course, and has presented symposia on standards of care and veterinary ethics.

Keeping pets pain and fear to a minimum is greatbut its not enough for a good quality of life. Animals need an environment in which they can thrive and be happy. And veterinarians are obligated to help make this happen.

Shutterstock.comAnimal welfare has been defined as the quality of an animal's life as experienced by that individual animal.1 This quality of life can range from a life not worth living, in which the balance of experiences is strongly negative, to a good life.2 The Five Freedoms archetype-which posits that animals should experience freedom from hunger, fear, pain and so on-suggests that good welfare is the result of minimizing negative experiences.3

Others, however, take a different approach. Preferred welfare states, they say, are those in which positive experiences predominate. For an animal to have a “life worth living,” its caretakers must not only minimize its negative experiences but simultaneously provide opportunities for positive experiences.4-8 This is where enrichment comes in.

What is enrichment?

Many environments in which animals are housed are impoverished in terms of mobility, feeding and behavioral opportunities.9 If an animal has too little control over its environment or too much predictability in its routine, it can experience stress, boredom and frustration, which can manifest as stereotypies and behavioral disorders.9 Environmental enrichment is a husbandry principle that seeks to enhance the quality of animal care by identifying and providing the environmental stimuli necessary for optimal welfare, both physical and mental.10

Environmental enrichment has received the most attention regarding laboratory, zoo and farm animals.10-13 In these species, environmental enrichment strategies have often included social housing, larger enclosures and environmental complexity.11 But recently, experts have suggested that household pets need just as much environmental enrichment as other animals in captive environments. For example, the Indoor Pet Initiative founded by Tony Buffington, DVM, MS, PhD, DACVN, at The Ohio State University provides enrichment guidelines to promote optimal welfare.14

But as well-meaning as these efforts have been, there's a problem with the term “environmental enrichment”: It implies that supplying environmental provisions to the animals we steward is elective-it “enriches” an already fulfilled life and therefore exceeds our basic obligations. But from the perspective of the animal, these provisions aren't really “enrichments”-rather, they're environmental necessities that satisfy the animal's behavioral and psychological needs within a housed environment.

Limitations to implementation

Environmental enrichment guidelines to optimize companion animal welfare include:

  • Physical provisions such as food, water and litter pans.

  • Sensory provisions, including visual, auditory, olfactory and tactile stimuli.

  • Provision of a suitable diet.

  • Provision of opportunities to exhibit normal behaviors via hiding places, exercise, toys, feeding devices, and horizontal and vertical spaces (for cats).

  • Provision of social or isolated housing.

  • Protection from pain, injury and disease.14-16

These guidelines can strain the resources of even the most well-intentioned pet owner. These resources include cost of supplies, veterinary care and time available to spend with the animal.

One study of cat owners found that most of them used far fewer food and water bowls than what is recommended by the environmental enrichment golden rule.17 Only 56 percent provided one or more food bowls per cat and only 36 percent had one or more water bowls per cat. A paltry 16 percent of cat owners provided at least one litter box per cat. Most (75 percent) did provide a moderately enriched environment for their cats, but only 5 percent provided a highly enriched environment, while 20 percent provided a poorly enriched environment.

The authors concluded that the main reasons cat owners didn't do more were: (1) lack of knowledge concerning various aspects of feline welfare and enrichment, and (2) the time-consuming nature of strategies they understood but didn't implement because of their busy lives.17

Ethical concerns

Dogs and cats have adapted to living with humans for more than 4,000 years. There is convincing evidence of the benefits people receive from the human-animal bond, including psychological (reduced anxiety and depression), social (enhanced empathy and self-esteem) and health-related (reduced blood pressure).18 Pets may substitute for an absence of human attachment and expand relationships and social contacts, while also ameliorating distress during difficult periods of transition such as divorce or bereavement.19 Given the advantages of the bond for people, a morally compelling question is whether we humans are meeting our obligations to the animals we choose as companions.

When we adopt a companion animal, we create an imbalanced relationship in which the animal becomes entirely dependent on its human caretaker for satisfying its welfare needs. And we don't necessarily do a great job meeting those needs. In a recent survey, only 68 percent of adults felt “very” or “somewhat” knowledgeable about companion animals.20 A study of owned cats concluded that owners who keep their cats permanently indoors generally provide an excellent standard of physical husbandry. But the same caretakers are far more likely to subjugate their cat's emotional needs to their own and provide inadequate attention to their cat's psychological needs.21

In my ethics class at the University of California, Davis, School of Veterinary Medicine, almost all veterinary students classify human relationships with animal companions as mutually beneficial. The vast majority of pet owners regard their pets as their friends (95 percent) or family members (87 percent).18 Unfortunately, these warm characterizations must be reconciled with the reality that approximately 4 percent of all owned dogs and cats in the U.S. are relinquished.22 Based on an estimated dog and cat population of 184 million,23 this comes to more than 7 million pets surrendered per year, of which 25 to 50 percent lose their lives.22,24 The most common reasons for pet relinquishment in descending order are:

  • Undesirable behaviors

  • Moving, rental or housing issues

  • Personal issues such as loss of employment.25


In the U.K., the Animal Welfare Act stipulates that owners and caretakers have a duty to care for their companion animals: “A person commits an offence if he does not take such steps as are reasonable in all the circumstances to ensure that the five welfare needs of an animal for which he is responsible … are met.”26 It's time to examine standards in the U.S. regarding both adopting and caring for pets. Regrettably, too many homes that companion animals are placed in are not “forever homes.” So how do we reduce the numbers of relinquished animal companions?

1. More stringent adoption requirements. Adoption of companion animals from breeders, shelters and pet stores should require a screening process, as occurs with the adoption of human children. When I adopted my dog from a breeder, I was asked to provide three letters of reference. My DVM colleagues were offended, exhorting me to find another breeder. I thought it was laudable for the breeder in question to try to ensure that Winston the Pug found a lifelong home.

We could start by providing educational materials and documenting via an examination that a potential guardian understands the husbandry, environmental enrichment and animal welfare needs of a dog or cat before adoption. This would screen out those without the knowledge, capacity or time to satisfy these duties. Pet owners who understand the welfare requirements of dogs and cats can better meet their pets' needs and are less likely to be surprised by behavioral issues.

2. Making relinquishment a last resort. Most people relinquish pets because they find breed- or species-typical behaviors such as barking or scratching unacceptable or because the animal develops undesirable (as perceived by its owner) behaviors-often as a consequence of inadequate social interactions such as being left alone all day. Commendably, fewer shelters are operating on an “on-demand” model, accepting dropped-off animals anytime for any reason, and more are only accepting animals by appointment to see if the human-animal relationship can be continued by providing resources to prevent displacement. In these cases relinquishment is indeed a last resort.27

The role of veterinarians

Small animal veterinarians should be concerned with the well-being of all dogs and cats as a result of our oath.28 Many behaviors that humans deem undesirable-such as scratching in cats and barking in dogs, which can result in relinquishment, declawing or debarking-are in fact normal. Veterinarians should serve as a conduit for educating clients about dog and cat behavioral needs, including the need for companionship and exercise.

Puppy, kitten and new-pet visits are a prime opportunity for this education. Veterinarians can discuss the importance of training at an early age and provide a list of provisions such as chew toys for dogs and scratching posts for cats. They can also provide clients with resources such as lists of local training classes, daycare options and veterinary behaviorists in case a referral is needed.

Pet owners have a responsibility to keep their animals in good body condition, as obesity predisposes them to orthopedic, hormonal and respiratory impairments. Obesity in dogs and cats is not a “lifestyle choice” whereby they sneak out for a meal after their owners are sleeping! Obesity is a serious and prevalent disease affecting over half of all dogs and cats, which can be remedied via dietary management, exercise (which benefits both animal and human), rehabilitation and treating medical causes when appropriate.29 In my experience, veterinarians seldom document obesity in their medical records or address it with pet owners. The logical conclusion is that practitioners may be hesitant to confront this issue for fear of alienating or jeopardizing their relationship with the client.

The fundamental question veterinarians face is whether our primary allegiance is to the animal or to the animal owner. If we observe undesirable behaviors in a patient such as anxiety or aggression, we may also be reluctant to acknowledge them and disinclined to associate these behaviors with environmental deprivation-which implicates the owner-out of concern for losing the client. Environmental enrichment is a moral obligation of keeping captive animals to ensure their welfare. And animal welfare can only be furthered if veterinarians view animal advocacy as our primary raison d'etre.


1. Keeling LJ, Rushen J, Duncan IJH. Understanding animal welfare. In: Appleby MC, Mench JA, Olsson IA, et al., eds., Animal Welfare. 2nd ed. Cambridge, Massachusetts: CABI, 2011;13-27.

2. Green TC, Mellor DJ. Extending ideas about animal welfare assessment to include “quality of life” and related concepts. New Z Vet J 2011;59:263-271.

3. Farm animal welfare council (FAWC). 2009. Farm animal welfare in Great Britain: past, present and future. Available at:

4. Mellor DJ. Enhancing animal welfare by creating opportunities for positive affective engagement. New Z Vet J 2015;63:3-8.  

5. Mellor DJ. Positive animal welfare states and encouraging environment-focused and animal-to-animal interactive behaviors. New Z Vet J 2015;63:9-16.

6. Mellor DJ. Positive animal welfare states and reference standards for welfare assessment. New Z Vet J 2015;63:17-23. 

7. Mellor D, Beausoleil NJ. Extending the “Five Domains” model for animal welfare assessment to incorporate positive welfare states. Animal Welfare 2015;24:241-253.

8. Mellor D. Updating animal welfare thinking: Moving beyond the five freedoms towards a life worth living. Animals 2016;6(21):1-20.

9. World Animal Protection Global Animal Network. Concepts in Animal Welfare: 15. Environmental enrichment. Available at:

10. Weed JL, Raber JM. Balancing animal research with animal well being: Establishment of goals and harmonization of approaches. ILAR J 2005;46:118-128.

11. Toth LA, Kregel K, Leon L, et al. Environmental enrichment of laboratory rodents: the answer depends on the question. Comp Med 2011 61;:314-321.

12. Maple T, Perdue BM. Designing for animal welfare. In: Zoo Animal Welfare. New York: Springer, 2013;139-167.

13. Waiblinger S. Animal welfare and housing. In: Smulders FJM, Algers B, eds. Welfare of Production Animals: Assessment and Management of Risks. Vol 5, ECVPH Food Safety Assurance. Wageningen, The Netherlands: Wageningen Academic, 2009;79.

14. The Indoor Pet Initiative. The Ohio State University College of Veterinary Medicine. Available at:

15. Ellis S. Environmental enrichment: practical strategies for improving feline welfare. J Fel Med and Surg 2009;11:901-912.

16. Ellis SLH, Rodan I, Carney HC, et al. AAFP and ISFM feline environmental needs guidelines. J Fel Med and Surg 2013;15(3):219-230.

17. Alho AM, Pontes J, Pomba C. Guardians' knowledge and husbandry practices of feline environmental enrichment. J App An Welfare Sci 2016;19(2):1-11.

18. Walsh F. Human-animal bonds I: The relational significance of companion animals. Family Proc 2009;48:462-480.

19. Sable P. The pet connection: An attachment perspective. Clin Soc Work J 2013;41:93-99.

20. Green C. Crunching the numbers. Animal Sheltering 2017;Fall 2017:29-33.

21. Neville PF. An ethical viewpoint: the role of veterinarians and behaviourists in ensuring good husbandry for cats. J Fel Med Surg 2004;6:43-48.

22. ASPCA. Shelter intake and surrender. Available at:

23. American Pet Products Association. 2017-2018 APPA national pet owners survey statistics: pet ownership and annual expenses. Available at:

24. American Humane. Animal shelter euthanasia. Available at:

25. Coe JB, Young I, Lambert K, et al. A scoping review of published research on the relinquishment of companion animals. J App Animal Welfare Science 2014;17;253-273.

26. Animal Welfare Act 2006. Accessed at:

27. California sheltering report 2013. Charting a path forward: reaching California's policy to save all adoptable and treatable animals. Available at:

28. American Veterinary Medical Association (AVMA). Veterinarian's Oath. Available at:

29. JAVMA News. Study: Over half of pet dogs and cats were overweight in 2015. June 15, 2016. Available at:

Dr. Barry Kipperman is the founder of Ironhorse Veterinary Emergency and Specialist Care Center in Dublin, California. He teaches veterinary ethics at the University of California, Davis, School of Veterinary Medicine and animal welfare and ethics for the University of Missouri-Columbia. Send questions or comments to