Surplus Animals: Stewardship on the Ark
American Association of Zoo Veterinarians Conference 1999
Albert H. Lewandowski, DVM
Cleveland Metroparks Zoo, Cleveland, OH, USA


This paper provides a frank, philosophic discussion of what constitutes a surplus animal in a zoological garden and the options that zoological gardens face in dealing with this surplus.


For decades, zoological parks and gardens around the world have aspired to attain consistent, reproducible results in breeding and raising the diverse species in their collections. One hallmark of a “good” zoo has always been a good breeding record. Success brings public acclaim, professional accolades, and an unspoken authority and status on the myriad committees of AZA that manage threatened and endangered species.

With the emphasis on providing optimum conditions for reproduction and scientific advances in medicine, nutrition, and animal psychology, an increased number of institutions are becoming successful in reproducing the species in their care. The regularity with which some species are now reproducing leads us to the brink of another problem: too many animals. With limited space in our institutions, limited funds in times of economic crisis, and spiraling costs, maintaining animals not essential to the immediate purpose of maintaining an adequate gene pool borders on irresponsible stewardship of already limited resources.


Surplus animals are surplus for myriad reasons.2 An unpaired male or female may be temporarily surplus and need only be placed in an appropriate breeding situation. The most responsible animal managers are relentless in obtaining suitable matches for their charges, keeping unpaired time down to a bare minimum. Animals whose lifespan may only be 12–15 years cannot be permitted to languish unmated for 2–3 years in a holding cage while we procrastinate about their fate.

Historically, some unpaired animals have been important symbols in the zoological community and served an indispensable function for public awareness. The gorilla Massa of the Philadelphia Zoo and Smokey the Bear of the National Zoo have been symbols of their institutions, recognized worldwide, superstars of the animal kingdom. Their role as ambassadors of the animal kingdom superseded other functions they might have had within the gene pool in their time. They provided a focus for media attention, attracting the general public and providing needed revenues.

Hopefully, more enlightened marketing will direct education about programs and populations, with less emphasis on the individual animal, which has been a double-edged sword. One recent success story was the transfer of the gorilla, Timmy, from Cleveland to the Bronx. Animal rights activists tried to block the nonreproductive, but popular animal’s move. A federal judge allowed the transfer, and Timmy has been a sire many times over. Because of the focus on an individual, the more responsible management might never have occurred.

Excess male offspring pose a surplus problem. With a 50/50 chance of producing either sex, when only one or two males are adequate to cover needs, a most uncomfortable situation is created. Bachelor groups are not particularly popular with zoological park managers or the public. Every zoo director wants baby gorillas.

Recently, the Taronga Zoo broached the subject of aborting a male gorilla fetus. In a bold and revealing statement, the zoo’s general manager, Will Meikle, stated that the zoo industry would have to decide what to do with surplus males in the global population. He noted that we are able to absorb the surplus today, but that it “will be a management problem for someone else in 10 years.” Unfortunately, some managers are more concerned with preserving the status quo than with the long-term effects on animal populations. Ten years will pass quickly.

Non-reproductive animals, whether due to advanced age or infirmary, are frequently in the ranks of surplus. Notable exception to the class of “non-reproductive” animals are those that serve as an integral part of a herd or group, such as the gorilla aunts.

The Species Survival Plans (SSP), in attempting to manage the gene pool for threatened and endangered species, frequently single out animals that are over-represented and recommend that they not be bred or rebred. They become surplus to the needs of the species.

Hybrid animals pose another class of surplus. In an attempt to maintain pure genetic lines, animals of mixed subspecific heritage have been relegated to nonbreeding desirability and contribute nothing to the gene pool for their species among reputable institutions. Notable examples include Sumatran x Bornean orangutans, tigers of mixed lineage or undocumentable pedigree, and dik-dik rendered sterile by cross subspeciation.

Genetic freaks, bred for their unusual color or pelage pattern, represent an interesting but evolutionary dead end that contributes nothing to the mainstream gene pool of the species. White tigers, albino wallabies, and black panthers have all generated much interest and filled our coffers with gold, but have contributed little to scientific conservation, unless the arousal of public awareness is touted. If we educated the public properly, these mutants would have no place in an institution managing for the conservation of a species.

Imperfect animals, aged animals, animals with medical conditions that we cannot cure—but because of our advances in medicine are capable of maintaining indefinitely—and animals for which medicine can improve (maybe) their condition at high cost and untold man-hours represent still another class of surplus. Do we maintain these animals for their good, or for our own impotent reasons?2

As responsible animal managers and as institutions dedicated to the advancement of science and the conservation of nature, what options are open for placing these animals?

Within our own institutions, these surplus animals are frequently maintained within the primary exhibit or warehoused in an off-exhibit area. Housed in the main group, multiple problems are often the result. The surplus animal is frequently low in the social structure and is subject to injury, or worse, injures a valuable breeding animal. Animals that would in the wild be driven from the group are confined in a limited area, interfering with the optimal social structure, interfering with optimal reproductive success, and decreasing the survivability of neonates that may be genetically more valuable to the species. Each exhibit has a limited carrying capacity due to the territorial requirements of each species.

If the surplus animal is housed in an off-exhibit area, the quarters are usually less desirable and less suitable than the main exhibit area. Temporarily keeping an animal in less-than-ideal areas until permanent placement can be made can be justifiable. A moral/ethical question arises when the “temporary” placement drags on for years. The quality of life for that animal now comes into question. Is this moral? Is this truly ethical?

In more callous terms, can my institution or any responsible institution reasonably afford the personnel, the time, the space, or the cost to maintain long-term a surplus animal, an animal that will be warehoused in suboptimal areas for the remainder of its life?

Where can a responsible institution place these animals? To not take up precious funds, time, space, tie up personnel, divert curators, keepers, and veterinarians from animals/species that require intensive management to maintain, to make optimum use of the resources at hand and contribute the maximum to serious conservation effort, these animals must be placed in a suitable situation.

Conservatively, a large carnivore like a tiger will in 1999 U.S. dollars cost a minimum of $25,000 to maintain for its lifetime. Primates generally are more expensive to maintain. Hoofed stock are less expensive to maintain. Extraneous animals, even one extraneous animal, rapidly become a burden on the system. Compounded over years and multiple animals, what institution would not rather focus its attention on progressive, fruitful programs over maintaining the status quo?

What other options are available?

Optimally, another party desires the surplus animal. The first institution of choice would be another zoological park. Good, professional care by an institution involved in a cooperative breeding program is most desirable. Knowing that an animal that we have invested time and effort into is going someplace that friends and colleagues will be caring for it always gives peace of mind.

When a direct zoo-to-zoo transaction is not possible, another option is the registered animal supplier. With their ear to the ground, licensed broker/dealers are often able to put together transactions with overseas contacts, zoos out of our usual sphere, or other institutions that may not have ready access to us. Often zoos go to considerable effort to limit second-party transactions in an attempt to keep unqualified persons from obtaining rare or dangerous animals.

A third alternative encompasses transactions with private breeders. Many fine institutions with high professional standards and impeccable, impressive records breed and raise unusual species, often more out of dedication and interest than profit. The use of profile sheets by zoos to document the experience and care afforded by these private breeders also helps to ensure proper care and the ability to track genetic lines, if required.

Private individuals constitute another pool of possible placement for some species. While I would not advocate the placement of lions or leopards with a private individual to maintain as a pet, judicious placement of neonates, injured animals, and long-term care cases might be suitable. Small, private menageries stocked with creatures of questionable parentage, cast-off pets, and zoological oddities contribute nothing to the efforts of conservation. These situations only hamper serious efforts by reputable institutions.

Public animal auctions? No responsible zoological park can justify disposing of surplus stock to the highest bidder. The AZA Code of Ethics condemns such practices. AZA members pledge to “make every effort to assure that exotic animals do not find their way into the hands of those not qualified to care for them.”1

An often-maligned outlet for surplus animals is legitimate medical research. An option more suited to primates than deer and politically incorrect in many circles, animals provided to medical research provide an invaluable service to mankind. Our colleagues in lab animal medicine provide no less concern and care for their charges than those of us working at zoological parks. Allowing surplus animals to go to medical research is a public relations nightmare, but perhaps the zoo community needs to voice an opinion in support of sound medical research that has made the lives of man and animal alike more tolerable.

The last option for a surplus animal not suited to medical research, too dangerous to situate with a private individual, too old for a dealer to place, too common for placement with any zoo, tying up valuable exhibit and off-exhibit space, costing thousands of dollars to maintain, not a high-profile animal, not having a life-threatening medical condition but not “perfect” euthanasia.3

Here is an animal that is to be warehoused until it dies of old age; an animal that for whatever reason has outlived a useful, productive life; an animal that deserves better than to be relegated to a less-than-ideal holding area for the remainder of its days. Morally, ethically, the quality of life for this animal becomes nonexistent.

As animal managers, we have the responsibility and obligation to make the effort to advertise that this animal is available. We must make a sincere effort to place this animal. Sometimes we may have this animal for several years before it becomes obvious even to the most optimistic of us that there will be no takers. We must then get on with our lives, assume the role of a responsible steward, make a difficult choice, and manage for the future.

We do not advocate rushing out and eliminating any surplus animal in our collections today. Much soul searching needs to be done, and as the need for space becomes more important, perhaps the surplus animals in our care need to make way for more endangered animals, for important breeding stock, and for SSP animals…not on a whim, but as part of a carefully thought-out, long-term part of responsibly managing our animal collections, of being a responsible steward.


“…I have moral responsibilities… to the animals under my care…(and need to) make every effort to assure that all animals do not find their way into the hands of those not qualified to care for them properly…(to) display the highest integrity, the best judgement or ethics possible, and use my professional skills to the best interests of all.”1

I need to be a responsible steward. The animals in my care, the animals that I manage, belong not to the past, nor to the present, but to the future.

Literature Cited

1.  American Zoo and Aquarium Association. 1998. Code of Professional Ethics.

2.  Lacy, R. 1995. Culling surplus animals for population management. In: Ethics on the Ark, B.G. Norton, et al. (eds.) Smithsonian Institution Press, Washington, DC. 187–194.

3.  Tannenbaum, J. 1995. Veterinary Ethics. Mosby-Yearbook, St. Louis, MO. 559–560.


Speaker Information
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Albert H. Lewandowski, DVM
Cleveland Metroparks Zoo
Cleveland, OH, USA

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