The zoologist Jordi Casamitjana lists ten powerful reasons why everyone, not just vegans, should not support zoos and public aquaria

I know them well.

In many respects, it could be said I am an expert on them, as they have been the focus of my professional career for years.

When in the 1980s I was doing my degree in Zoology at Barcelona University, I used to go to the zoo there very often. Even when I began my PhD studies in Ethology, I did an observational study of the chimpanzees at Barcelona Zoo (about their laterality, whether they were right or left-handed), so I was in the zoo practically every day for months.

When I left Catalonia in the 1990s and tried to find another country to live in where I could be both a zoologist and an animal protectionist, I visited many zoos in different countries before I settled in the UK. In every zoo I visited in France, Belgium, the Netherlands, Germany, and Denmark, I took copious notes with observations about the animals and how they were kept. 

The first proper zoological job I had in England was as a resident Research and Rehabilitation coordinator of the Monkey Sanctuary in Looe, Cornwall, which, although it was a sanctuary for Amazonian woolly monkeys, had a zoo licence because it was legally a zoo (as it was open to the public). I was even part of the woolly monkey EEP (European Endangered Species Programme), the kind of thing “elite” modern zoo professionals are part of, and I participated in several of its meetings. A few years later I became one of the directors of the sanctuary (as all experienced keepers would become at one point because it was run as a co-operative), so I have been, technically, a director of a zoo in the UK.

Then, when I left in the year 2000 and I became the Zoo Check Scientific Researcher and Co-ordinator of the Born Free Foundation, my job was to investigate zoos and write reports about them. I inspected over 200 zoos doing that, mainly in the UK. Even when I became a freelance investigator after that job, I still kept investigating zoos, and I wrote very comprehensive reports on public aquaria and the UK zoo inspection system.

So, yes, I know zoos well, and after all these years I can say with conviction they all should be phased out and laws should be passed everywhere in the world to prohibit them from breeding any animals and acquiring new ones.

I am now an ethical vegan (since 2002), and such an uncompromising opinion about zoos is what you would expect any vegan like me to have as we are against any animal exploitation, but the truth is that zoos are so bad that even vegetarians and meat-eaters should stop supporting them. 

Why? I can list a few key reasons here.

1. Zoos Are Prisons for the Innocent

Captured Monkey from Abkhazia By gans33 via Shutterstock (442107460)

Zoological collections (the technical term for zoos) come in all forms and shapes, but they all have two things in common: they keep wild animals captive for the entirety of their lives, and they are open to the public. Those places that just keep wild animals for a short period while they are being rehabilitated due to injury or any other problem are not zoos, but wildlife rehabilitation centres. Those places that keep wild animals to give them refuge from people after being rescued from circuses, zoos, work, or other forms of exploitation are not zoos, but wild animal sanctuaries (and they should never be confused with fake sanctuaries which are zoos that keep exploiting such animals for profit but they use the term “sanctuary” to deceive paying visitors). Those places where they keep domestic animals instead of wild animals and exploit them for profit are farms, not zoos (and those open to the public are called “open farms” or “Petting farms”).

All zoos keep wild animals in captivity, and wild animals are not physically or mentally equipped to live in captivity, as they evolved in the wild and have not been genetically modified through artificial selection to make them cope better with it. Therefore, when forcibly kept in captivity against their will (and that is why they need to be kept enclosed as otherwise they would escape), animals in zoos suffer all sorts of mental and physical problems, and as most are kept in enclosures (a euphemistic term for cages) their entire lives, their suffering becomes chronic, experiencing it for years — and even decades.  

Forced captivity is used in humans as a form of punishment for criminals, and in most civilised countries that have abolished the death penalty, those who are condemned to life behind bars are receiving the highest possible punishment. However, zoo animals are not criminals. They have not done anything wrong, and yet, they are punished with the same life sentence as mass murderers and sadistic serial rapists. Zoo animals are innocent, and zoos are the prisons they have been condemned to spend their entire life confined in, often since the very first day they were born. An estimated one million wild vertebrate animals are wrongly incarcerated for life. Can it be any greater injustice than that?

2. Zoos Violate Rights by Sacrificing Individuals

Animal rights activists carrying signs about rhinos and elephants By BluIz60 via Shutterstock (797505901)

Violations of human rights are very serious transgressions but those who commit them often claim that they were trying to sacrifice the wellbeing of some individuals for the benefit of the community. For instance, police arresting and beating up someone for the way they look to supposedly protect the community from crime, kidnapping boys to train them as soldiers to win a war; or forcing sterilization for disabled underage girls to avoid the burden of the state in having to deal with orphans. Human rights are all about giving individuals the protection from being exploited and/or oppressed for the benefit of the collective or even an abstract cause.

Violations of animal rights are exactly the same. Sacrificing individuals for the benefit of another species, or even the collective of the species they belong to, is a violation of animal rights. This is what zoos do thousands of times every single day. Zoos justify the keeping of every single animal they “own” by saying they do it for the benefit of someone else, other than the animals themselves—the very definition of violating someone’s rights. Zoo operators justify keeping individuals of endangered species for the benefit of the species they belong to. They justify the keeping of cute individual animals for the benefit of the education of humans. They justify the keeping of some rare individual animals for the benefit of human science. Irrespective of whether such justifications are real or just propaganda — most of the time this is what they are and the animals are just exploited for profit— they are unequivocal confessions that zoos systematically violate the rights of individual animals, sacrificing them for the benefit of others. This is unethical, and zoos do it every day.

Imagine if a kidnapper justified keeping a victim in a dungeon for life for education, conservation, or research purposes. Imagine that such a kidnapper said that the victims belong to a very uncommon demographic (such as someone from an ethnic minority, or with a rare genetic makeup), and because of that he regularly allows children to visit his dungeon to “learn” about such races or genetic conditions; or claiming that researchers are doing experiments on his victims for the benefit of science; or even claiming that such individuals are the last of their kind, so he is “preserving” them for future generations. Would you expect such a criminal to be left unpunished if he uses such defences in court? Does it matter which race the victims are? Does it matter which genetic peculiarities they have? Does it matter which species they belong to?

Unfortunately, the laws of the majority of countries do not class most violations of non-human animal rights as crimes, they only do so for violations of human-animal rights. But this does not mean decent people “pardon” those who commit such violations. This does not mean that zoos, which commit them every day, are exempt from the moral duties that the rest of society decided to honour. Sacrificing individuals against their will for the benefit of others is a violation of such individuals’ rights, and whoever caused those sacrifices is doing something morally — and sometimes legally — wrong. Any organisation that does that as its Modus Operandi in its standard practices is an undesirable unethical organisation that should not exist. Multiply this wrongdoing for the thousands of individuals whose lives have been wrongly sacrificed and such an organization is doing thousands of wrong things every single day. That’s unforgivable, and happens all over the world (there are over 10,000 zoos across the globe).

3. Zoos Harm the Non-Human Animals They Keep Captive

Suffering bear in a zoo By Angyalosi Beata via Shutterstock (1715316085)

Zoo captivity always has the effect of reducing the space available for the animals to move (which negatively affects the body of the animals), reducing the number of stimuli received (which negatively affects the senses of the animals), and reducing the free choices the animals have (which negatively affects the minds of the animals). Any captivity causes this, but many animals can cope with it if it is just temporary. However, when it is for life, that’s another story, as wild animals are not adapted to such life, and with time, their coping mechanisms begin to weaken.   

I studied the issue of the reduction of space a few years ago using a random sample of zoos in the UK. I concluded that mammals kept in UK zoological collections during the period 2000-2001 were confined in enclosures that, on average, had an area 100 times smaller than their minimum home range in the wild (the minimum space they need for normal life), and in the case of megafauna, 1000 times smaller. For instance, an Asian elephant’s minimum home range is about 100 km2 to 300 km2, and no zoo can provide this. As far as stimuli are concerned, no matter how much behavioural enrichment zoo keepers devise, it will only be insignificant compared with what the animals experience in the wild, and, as we all know, zoos decide what animals should eat and when, where should they go, who should they meet, and even with whom should they mate, leaving very little room for them to choose to do what they want to do. And all this is even worse with social species that have social requirements zoos cannot provide. With time, all these restrictions have negative animal welfare consequences.  

Mental problems associated with living in a zoo are what is commonly known as Zoochosis. The most common symptom is stereotypic behaviour (such as pacing, circling, head bobbing, neck twisting, overgrooming, rocking, spiralling, Interaction with Transparent Surfaces, tongue-twisting, bar biting, etc.). Some animals are prone to show this abnormal behaviour sooner than others, as is the case of big cats, elephants, bears, or chipmunks. Sometimes the problems get so bad that they lead to lethargy, eating disorders, vomiting/regurgitation, coprophagia, and even self-mutilation (abnormal behaviours that have also been reported in confined humans). 

In 2023 the Born Free Foundation launched a new report exposing the true extent of the suffering of polar bears in zoos across Europe. The report, titled “Born to Roam: The Suffering of Polar Bears in Zoos”, outlines the continuing plight of the polar bears who are still incarcerated in zoos (151 in Europe and 61 in North America). 

Many zoos fail to provide even a minimum legal standard of care, which makes the problems worse. In 2017, South Lakes Safari Zoo in Cumbria, England, was exposed when investigators discovered that nearly 500 animals died there in under three years from causes ranging from malnourishment, hypothermia, and lack of veterinary care to outright neglect. The Dr Juan A. Rivero Zoo in the western coastal town of Mayaguez, Puerto Rico, permanently closed in 2023 following years of negligence, a lack of resources, and deaths of animals. And we are not talking about a few bad apples here. A 2013 study by Bristol University found that many British zoos fail to provide animals with the required minimum standard of care — imagine how the care would be in countries that do not even have a zoo licensing system, let alone one so strict as the UK one.

4. Zoos Seek Unjustifiable Exoneration of Their Wrongdoing

lion in a cage closeup By MLReed via Shutterstock (787685107)

One thing that pro-zoo supporters do is to try to cover up the common wrongdoing of zoos with the occasional anecdotal “good things” that just a minority of zoos may have done. Returning to the simile I used in the previous point of a kidnapper trying to justify keeping his victims captive, now imagine that his defence for his kidnapping charges is that he gives donations to charities, and helped once an elderly person crossing the road. In other words, trying to be exonerated for his kidnapping with things he has done that are not bad. We know this would never work in a court scenario as normally criminal court cases are judged based on the evidence of having committed a crime, not on the evidence of having done things that are not crimes besides the crime the suspect was charged with.

This sort of unjustifiable exoneration of wrongdoing demands is common among those who support zoos. For instance, when zoos are accused of keeping animals who are not endangered under the false justification of keeping them for conservation purposes, pro-zoo people often claim that there have been particular conservation advances some zoos have made in the past, even if they are rare and their success may be questioned. Some of such excuses often used are the reintroduction of Mexican wolves into the wild by several American zoos, the stopping of the extinction of pandas after a captive breeding programme in zoos, the rehabilitation of Californian condors at the Chapultepec Zoo, and the rehabilitation of endangered marine turtles by zoos. Even if these cases were genuine and were indeed successful conservation projects, even if the claims of such projects having “saved” certain species are not scrutinised to check that they are true and the threats of extinction have disappeared, and even if more individual animals benefited with this programmes than animals who were negatively affected by them (It could be argued that these three assumptions are far to be proven right in most cases), they would still represent a tiny proportion of successes compared with the huge amount of “conservation” failures. 

Each and every animal in zoos never attempted to be rehabilitated back into the wild, or never been part of a coordinated official captive breeding programme, or not even belonging to a species threatened with extinction, but still kept captive at a zoo under a conservation excuse, is a “conservation failure”, a wrongdoing, that cannot be exonerated by the far and few conservation successes some zoos may claim. In the year 2000, I co-authored a report that quantified the proportion of “successes” from the conservation claims UK zoos boasted about — UK zoos are considered one of the most modern in the world, and must follow one of the most rigorous regulations that include conservation conditions. Looking at a random sample of 104 zoological collections, representing 25% of all UK zoos, the study concluded that less than 5% of the species or sub-species kept in British zoological collections were classified as endangered or worse by IUCN, less than 3% were part of any 2000 European Endangered Species Programme, and less than 1% were directly involved in reintroduction projects during that year (regardless if they were successful or not). So, any potential “successes” could not reach more than 1% of the species kept captive. Imagine how much smaller that percentage would be if we count individuals rather than species (possibly less than 0.1% considering that endangered species breed less in zoos). 

These unjustified exoneration demands would be like a bank robber who robbed one bank every day for 50 years claiming he cannot be guilty of bank robbery because he once entered a bank to make a deposit of £10. You cannot avoid the blame for doing something wrong constantly with the claim you have done something else right once or twice.

5. Zoos Miseducate Children 

kid watching the shoal of fish swimming in an aquarium By Olesia Bilkei via Shutterstock (281921918)

One of the often-heard excuses zoos put forward to justify not being shut down for being unethical is that they perform an educational service to the community. There is no doubt that there is “information” in zoos and that schools often take their pupils to zoos aiming to receive an education lesson from them. However, having information does not mean being educational, and attempting to teach does not mean the lessons will be educational enough. In fact, not only most zoos’ educational value is very poor, but they often impart miseducation.

Regarding the poor education performance of zoos, another investigation I did after I left Born Free and became a freelance investigator shows some quantifiable evidence of it. This one was on UK public aquaria commissioned by Freedom for Animals (then CAPS) and was conducted in 2004 (remember that the UK zoos are considered pioneers in the conservation, education, and research excuses, so although the data may look a bit old, this is what we most likely find elsewhere now). The study, which covered a random sample of 31 aquaria visited representing 55% of the total, concluded:

  • 83% of the UK public aquarium visitors do not read the contents of live exhibit signs except perhaps the animals’ names, and 95% of the visitors do not read the entirety of exhibit signs.
  • 41% of the individual animals seen in UK public aquaria have no signs identifying which species they belong to.

Regarding miseducation, these are the most common “wrong lessons” with erroneous information zoos teach to those going there to learn:

  • It is OK to keep someone captive for the entertainment of someone else
  • It is OK to make fun of others because they look different from you
  • It is OK to force someone to have sex with someone else if we want to preserve some rare genes
  • It is OK to keep wild animals in completely different habitats from those they evolved in, with the wrong temperature, humidity, light, and food
  • It is OK to mix animals they would never meet each other in the wild, and let them interchange pathogens they never encountered
  • It is OK to kill someone to vacate a residence and allow someone more important to live in it
  • It is OK to kill someone if you think there are far too many individuals like that one
  • It is OK to feed wild animals food they would not normally eat in the wild
  • Pacing up and down, endlessly walking in circles, bobbing the head constantly, or removing all the fur or feathers are perfectly normal behaviours of wild animals
  • Lions, snow leopards, jaguars and tigers live in the same place (as do gorillas, orangs, and spider monkeys)
  • Social animals such as elephants or orcas happily live their entire lives on their own
  • Wild animals don’t eat fruits from trees but from bowls
  • Predators such as cheetahs don’t hunt live prey but eat carrion
  • Fishes like to play with their own reflections
  • Dolphins get their food by performing tricks
  • Flying birds may live their entire lives happily without flying
  • Polar bears can comfortably live in Florida, and Giraffes can live in Alaska

6. Zoos Are Outright Liars

Lemurs keeper with their animals By meunierd via Shutterstock (1162698187)

If we try to find one thing zoos are good at, I would say that deception would be it. The PR departments of zoos are very good at hiding all the wrong things that they do, inflating all the good things, and successfully deceiving the public into believing zoos are not what they really are. Zoos are profit-making businesses based on entertaining paying visitors by showing them animals they would not normally see. Their business model is the same as the old-fashioned “freak shows”, where people paid for seeing humans with deformities, rare genetic conditions, or just “odd”. The zoos that make more money often have more “rare” animals than the average zoo, often boasting they are the only ones that “exhibit” animals who are so rare that belong to endangered species. 

However, in modern times, being a profit-making freak show that exploits sentient beings against their will by charging visitors to watch them (the true definition of a zoo) would not give zoos a very good image, so their PR teams had to change that. They had to disguise zoos as something else. Something like a conservation centre, an educational school, or a research facility. The Conservation, Education, and Research image zoos try to sell to the public is, putting it simply, a smoke screen to hide their true nature. In Europe, the inclusion of these three criteria in law came in 1999 with the European Zoo Directive (Council Directive 1999/22/EC), and since then zoos must make an effort to be convincing enough when parading this lie (even to official zoo inspectors). 

In several of the points above I already exposed the zoos’ lies of conservation and education, but let me restate it again. Zoos saying they are institutions that save species from extinction by reintroducing animals back into the wild is like restaurants saying they are institutions that resuscitate dead people (based on the occasions waiters may have saved customers’ lives by calling an ambulance if they fell ill while eating dinner). In both cases, they would have deliberately departed from the truth to deceive others to such a degree that the adjective “liar” would fit them well. 

The claim that research is an essential part of zoo work is also a lie. Scientific research (rather than self-serving “husbandry” research) is very rare in zoos. For instance, the study I made in 2000 on UK zoos also looked at this and concluded that all the scientific papers published from 1977 to 2000 about research made on all Large Zoos and Safari Parks in the UK only represented 0.05% of the zoological papers published during the same period. It also concluded that the average UK zoological collection produced a single scientific paper every 15 years (in the very land of the famous Zoological Society of London that runs London Zoo).

The conclusions that come from scientific research in zoos are often wrong because the zoo settings negatively affect the results. They are often corrected when the animals are studied in the wild instead, as their behaviour in captivity is often abnormal. Zoos are not the right places to study many of the things researchers study in zoos (but they do it anyway so the research smokescreen can be deployed). For instance, the concept of “alpha male” was first used in 1947 by Rudolf Schenkel of the University of Basel, who based his findings on researching the behaviour of grey wolves (Canis lupus). It means one male is the “boss” of the pack, and not only makes the most important life decisions for the group but also dominates all the other individuals physically and reproductively. This concept was later extended to other species, including humans. However, when people began studying wolves in the wild, they could not see alpha males. Instead, now we know a pack is usually a family consisting of a breeding pair, who are equally dominant, and their offspring of previous years. How was this error made? The explanation is simple: Schenkel studied captive wolves in zoos, and the “alpha male” was an anomaly caused by captivity. Zoos make scientists fall into spreading misinformation (I fell for it myself, as I have done studies in captive wild animals, but now I recognise they had very limited scientific value).

If you ever visited a zoo and asked questions about something that does not seem to look quite right, the chances are the keepers will lie to you about it. If you ask why elephants keep rocking back and forth (a type of stereotypic behaviour), keepers may tell you they are happily dancing. Or if you ask why an animal seems unusually lethargic (which could also be an abnormal behaviour, as in some zoo animals their zoochosis gets so bad that they kind of “give up”), keepers may tell you they are just resting. 

Another common lie from zoos is to say to their visitors that they have managed to replicate the natural habitats of the animals they keep. The idea that a small tank can replicate the ocean, a cage can replicate the savanna, or that a metal frame can replicate a forest, is preposterous, but many people fall for this lie because they do not really know what the true habitat of the animals is, and the education departments of zoos will not help them to find out, as this would expose how inadequate the zoo cages (sometimes outrageously called “habitats”) are. No matter how lush a zoo enclosure may appear to an average zoo visitor, even the much bigger enclosures of safari parks, for the animals in it it is just a boring barren cage they want to escape from (I remember that, when I did all my inspections of UK zoos, safari parks did not score much better than traditional inner-city zoos). 

7. Zoos Don’t’ Save Animals, but Condemn Them

Condors in the forest By FRAYN via Shutterstock (1152937418)

We often hear pro-zoo people claiming that zoos “save” animals, either by saving species from extinction, by saving animals from the “horrors” of living in the wild, or by saving animals from the Illegal traffic of exotic species, Illegal hunting, natural disasters, circuses, customs confiscations, or abandonment. Most of these claims are lies because they are either exaggerations, or the “saving” was done by somebody else, and zoos falsely claim credit. 

For instance, despite zoos claiming to have saved pandas or Californian condors from extinction via their captive breeding programmes, the truth is that their extinction threat has not disappeared, so they have not been saved yet. In 1992, Californian condors were reintroduced to the wild in California, in Arizona in 1996, and in Baja California and  Mexico in 2003, which increased the population to approximately 500 wild individuals. However, they have not been saved, as they are still critically endangered because of habitat loss, lead poisoning, poaching, power-line accidents and DDT contamination, and captive breeding programs have not eliminated these threats (in the early years of the program, a significant number of reintroduced California condors perished after being released owing to lead poisoning and accidents with power lines). 

The same with Pandas. They are still classed as a threatened species (one step away from the classification of endangered), and it is arguable that their recent recovery is more due to the establishment of a system of protected areas in China that prohibited hunting, logging, and other harmful human activities than the captive breeding programmes themselves. 

Another example is the case of the Arabian Oryx, which was driven to extinction in the wild in 1972. In 1962, the Phoenix Zoo initiated a captive breeding experiment starting with nine oryxes who produced over 200 offspring in the end. These oryxes were sent to zoos around the globe, and the first Arabian oryx was reintroduced to Oman in 1982. There are now around 1,100 wild oryxes in Oman, Saudi Arabia, and Israel. Have the Oryx been saved by zoos? Not quite. The problem is that the majority of the wild oryxes put back into the wild are male, so the absence of gender variety may soon lead to the extinction of the population again, as their hunting (the main threat for their extinction, continues). 

Captive breeding programmes alone, especially if run by zoos far away from the natural habitats of the animals, could never save a species from extinction as they are expensive and do not address the causes of extinction. They are often a distraction and take funds away from genuine in situ conservation projects which do address them (in 2013, Freedom for Animals revealed that the UK’s largest aquarium operator, Sea Life, could trace less than 3 pence per visitor to in situ conservation projects). The California condor reintroduction project in the US has cost over $35 million.

Additionally, such captive breeding programs cause a loss of genetic diversity because they often involve a certain level of inbreeding, as the population of animals they breed is small and often not too distantly related. That, coupled with the fact that animals born in captivity may have lost the ability to survive in the wild because they have not learned the right skills, explains why so many reintroductions of zoo animals have failed. 

There is something important that zoo conservationists often ignore. If the last remaining individuals of a species are kept alive in zoos, the species has already become extinct, as the place for a species to be is the wild habitat where it evolved, and captive animals born in captivity may already have “lost” the ability to survive in the wild. You could well say you save a species from extinction if you keep the DNA of the last individual alive in a jar, right? Genetically speaking, it’s all there, but that is not the animal, is it? The same could be said of the last individuals still alive in zoos. They are not the actual animals either. They are shadows of them, having lost many of their behavioural adaptations. They are “incomplete” approximations of the animal, but if they can no longer live and thrive in the wild, the species is already gone — being kept in a jar or a cage will not do.

Additionally, it could be said that zoos have caused the extinction of many more animal species than prevented it, as it is not uncommon that the last survival of species that went extinct in modern times died in a zoo. For instance, the case of the thylacines, or Tasmanian wolves. By the beginning of the 20th century, the increasing rarity of thylacines led to increased demand for captive animals by zoos around the world. Despite the export of breeding pairs, attempts at rearing thylacines in captivity were unsuccessful, and the last thylacine outside Australia died at London Zoo in 1931. As the last known thylacine to be killed in the wild was shot in 1930, one can say that zoos were directly involved in the extinction of these animals, because the last one was captured by a zoo.

Regarding the “saving” of individual animals from circuses, wildlife trade, etc., this is not what zoos do, but this is the work of animal protection organisations unconnected to them. It may be that, for practical reasons, zoo facilities have been used to keep some rescued animals when no sanctuaries are available (it happens, but it is rare), but this does not mean the rescuing was done by the zoos. When the authorities confiscate animals from the illegal pet trade, they are the ones that save them, not the zoos which may end up keeping them if no other facilities are found, and then try to get credit for their rescue. Most reputable animal protection organisations would never give such animals to zoos and would try to create sanctuaries instead if they were not available. In fact, several animal protection groups save animals from zoos and remove them from their miserable life there to be taken to wild animal sanctuaries. For instance, in 2023, all the animals from Waccatee Zoo in Horry County, South Carolina, which closed due to legal action initiated by PETA, were taken to sanctuaries such as The Wild Animal Sanctuary (TWAS).

8. Zoos Kill Animals for Profit

Feeding grass to giraffes in zoo By Aleoks via Shutterstock (523639228)

You may think that the business of killing animals for profit is confined to animal agriculture and hunting. Zoos do that too, all the time. They do that in two ways: by keeping animals in the wrong environment for them for a long time until they succumb to diseases or husbandry problems they could not overcome, or by outright killing them if they consider them “surplus to requirement”. 

Each animal who dies in a zoo has been killed by the zoo, as the animal did not choose to be there, and was forced to stay. For instance, according to Mason & Clubb (2004), 40% of lion cubs in zoos die before one month of age, while in the wild only 30% of cubs are thought to die before they are six months old and at least a third of those deaths are due to factors which are absent in zoos, like predation. In the wild, the average lifespan for an elephant is 50 to 70 years, but in zoos, the medium lifespan is under 20 years. In public aquaria, the mortality rate is much higher, as many fishes die in tanks every week. In addition, animals who try to escape from zoos are often shot dead, as was the 2022 case of three chimpanzees shot dead after they escaped from their enclosure in Furuvik Zoo in Sweden. All these premature deaths are caused by zoos

No animal has died in zoos from natural causes because zoos are not natural to them. In the wild, they may die from being predated, from lack of food when resources are scarce, from natural disasters such as wildfires, from territorial fights, or from common diseases and parasites. These would be the natural causes of their deaths, and they have evolved to deal with them in the best way they can. However, in captivity, they die from different diseases (exotic to them), husbandry problems, animal aggression they cannot avoid (but they could in the wild), degenerative diseases, (the fact that in some cases they may live longer in captivity than the average wild individual of their species means that they develop some degenerative diseases they are unlikely to experience in the wild), and other unnatural causes they have never evolved to deal with, so they are more likely to suffer more by experiencing them. 

As the ultimate purpose of zoos is profit-making (regardless of how that is disguised to attract more paying customers), all this killing happens for profit. And we are not talking about a handful of individuals either. According to the Association of Zoos & Aquariums (AZA), there are roughly 800,000 animals in the custody of accredited AZA facilities (theoretically the best zoos), all of which will end up being killed by the zoos and their activities.

Killing animals because they need space for other animals, because zoo “experts” do not like their genes, or because they want to “exhibit” someone different, is something zoos regularly do. We are not talking about euthanasia to prevent animal suffering, but killing healthy animals (as healthy as they can be in a zoo, anyway). According to In Defense of Animals, up to 5,000 healthy zoo animals are killed each year in Europe, and a Freedom for Animals study revealed that at least 7,500 animals (possibly up to 200,000) are deemed ‘surplus’ by European zoos and may be subject to killing. 

This is often done secretly. In 2010, a German zoo was prosecuted for breaching animal welfare laws after it killed three tiger cubs because they were deemed not pure-blooded. In 2011, a former employee of Knowsley Safari Park in the UK said, “Culling was being used as a means of training instead of being carried out in the kindest and most humane way.”Sometimes this “culling” is done in the open (as was the case of the shooting of Marius the Giraffe in Copenhagen Zoo in 2014). 

This killing for profit is not that different from what factory farms do. Zoos keep animals under extreme confinement and then they kill them when they are no longer profitable. Factory farms do the same, the only difference is that zoos keep them for longer as just showing them to the public is what generates the profit, while factory farms get the profit from selling their flesh, and this is why they kill them when they are still young. 

9. Zoos Are Public Health Risks

Toxocara canis embryonated egg with larva By olgaru79 via Shutterstock (386279956)

Zoonoses are diseases that can be transmitted from non-human animals to humans, and the other way around. Some of these infectious diseases may become epidemics, or even worse, pandemics (as in the case of COVID-19). Newly emerging diseases often appear when different species that carry several microbes without causing them illness enter into contact with each other. Then, the genetic codes of both microbes may be recombined producing a new one that could be more pathogenic, or, alternatively, one of the animals cannot fight the new microbe carried by the other with their immune system allowing it to multiply, creating a disease that spreads much faster. 

The other factor that increases the chances of new emerging diseases becoming pandemics is if the infected animals are kept in captivity in high densities. This is because it becomes easier for the microbes to infect other individuals, and often the immune system of captive animals is compromised by stress, so they cannot fight the infections well. Both risk factors, mixing different species and the high density of captive individuals, are what we find in zoos. Although web markets where wildlife trade occurs are generally blamed for these kinds of public health problems, there is no reason to believe that zoos do not pose a similar risk. In fact, it could be argued that the risk is even higher, as in zoos it is more likely to find more mixing of species that would never be in contact with each other in the wild (and some may be carrying their own microbes that have not shown up yet as their natural host kept them at bay), and many zoos allow physical contact between visitors and animals (like in the petting zoos inside many big zoos).

When I was working at The Monkey Sanctuary in Looe, one of my jobs was to plan for the rehabilitation of all the monkeys back into the Brazilian Amazon. The project was going well, but just before moving them to Brazil, we had to test all the monkeys to check they did not carry any diseases. Unfortunately, the project had to be cancelled when we discovered that many of them carried a virus, the Woolly Monkey Hepatitis B virus. We did not know whether they acquired it in captivity or monkeys in the wild also carry it, but we had to stop the project just in case. The interesting thing was that the monkeys with the viruses did not show any symptoms, but they were just carrying them. In the same way that preventing them from travelling to Brazil was the sensible thing to do, equally, preventing them from going to any zoo would also have been (not that they would ever be taken to a zoo as these were sanctuary animals, but other woolly monkeys tested in zoos were also found to carry the virus). And yet, we only discovered the virus because we tested for them. How many animals are moved from zoo to zoo carrying pathogens not yet detected as nobody is testing for them? 

10. Zoos Are Bad for the Environment

Altaltis Aquarium and Underwater Zoo in Dubai By Gervasio S. _ Eureka_89 via Shutterstock (761891299)

You don’t often hear that zoos are bad for the environment, but they are. In addition to the fact they divert funds away from proper conservation initiatives, or that they may remove key individuals from their natural habitats which may harm the ecosystems, they have a high carbon footprint, contributing to our current climate crises.

We know that animal agriculture is one of the major contributors to global heating because of the CO2 the animals exhale, but also the methane, which has a much more powerful greenhouse effect. Guess who else emits these gases. Zoo animals. They all will breathe out CO2 and many would also release methane, in addition to all the faeces that may end up contaminating the nearby areas, or, at the very least, put pressure on the local sanitation systems. 

We must then add all the energy wasted to keep animals from warm habitats still alive in cold places where the zoos are, and the other way around. And, of course, the food. Zoo animals need to be fed every day, so that means vegetation needs to be cut and transported to them if they are herbivores, and if they have very specialised feeding requirements, that would increase the energy and transport miles involved in their diet. Imagine how much energy a public aquaria with big tanks needs to use to keep all the lights and water filters constantly going.

We then have the fact that, as most vegans do not visit zoos, the catering of the shops and cafeterias of zoos is heavy in animal products, making it worse as far as contributions to global heating are concerned than the average eatery.  

Modern zoos are also notorious for interchanging animals with one another (which means transporting sometimes very big animals in special planes or vehicles for long distances), and for building extravagant enclosures to impress the public, all of which as an associated carbon footprint to add. No matter how much we advance in reducing our carbon emissions, trying to replicate habitats from all over the world (and fail at it every time) and keeping animals alive with very high husbandry demands, all together in one place, it is going to be far more environmentally damaging than attempting to preserve the natural habitats and conserve their species in situ in the wild, where they belong.    

Other Reasons Why People Should Not Support Zoos

gorilla in the London zoo By Pack-Shot via Shutterstock (2189614607)

I could keep adding more and more reasons for people not to support zoos, but I think I have mentioned the most important ones. I could have talked about how many zoos engage in forced labour by making some of their inmates perform tricks for the public in exchange for food (as was the case of Tokitae the orca who was forced to perform for decades until public pressure made Miami  Seaquarium stop). 

I could have talked about how zoos may indirectly “steal” funds from genuine animal sanctuaries and in situ conservation projects by convincing the public to visit them rather than giving substantial donations to such projects (when London Zoo spent £5.3 million on a new gorilla enclosure, the chief consultant to the UN Great Ape Survival Project said he was uneasy at the mismatch between lavish spending at zoos and the scarcity of resources available for conserving threatened species in the wild).

I could have talked about how zoos, by using terms such as “specimen” or “exhibit”, promote the idea of animals as commodities that can be “collected”, sold, interchanged, or paraded as collectors often do with the objects of their obsessions. 

I could have talked about how many zoos are still taking animals from the wild despite their PR teams’ claim they no longer do it, as is the case of most public aquaria where most of the animals they keep are wild-caught, and others (In 2010, Zimbabwe planned to capture two of every mammal species found in Hwange National Park and send them to North Korean zoos). 

I could have talked about how zoos promote the idea of “animal attractions” and how this has led to so many animals being exploited in horrible ways (such as roadside zoos, circuses with animals, animal rides, etc.) 

I could have talked about how zoos defend each other even when the worst ones have been prosecuted for animal welfare violations or are even closed down by exposés from animal rights organisations (The World Association of Zoos and Aquariums, or the European Association of Zoos and Aquariums often criticise animal rights organisations even when these expose “bad” zoos breaching their own rules).

I could have talked about how many of the regulations created to guarantee the well-being of zoo animals fail to do so either because they are weak or poorly enforced (when I investigated the UK zoo licensing system in 2011 I found that 95% of zoos should have had legal enforcement action taken against them at some time between 2005 and 2011 but they did not, and only two instances of the correct enforcement action were identified).

I could have talked about the connections between zoos and other forms of animal exploitation, such as circuses with animals, the exotic pet trade, etc (Noah’s Ark Zoo Farm had been breeding camels from the Great British Circus for several years and in 2009 obtained three tigers from the circus). 

I could have talked about many other reasons for considering zoos outdated institutions that should no longer be supported, as there are genuine alternatives to conservation (e.g. in situ projects), education (e.g. documentaries), research (e.g. field research), tourism (e.g. museums), and entertainment (e.g. theme parks) that people should support instead because they do a much better job than what zoos do. 

What should be done is obvious to me. Instead of supporting zoos, people should stop visiting them and should pressure their legislators into passing new laws that phase out the zoo industry altogether. “Phasing out” rather than “banning” is the right policy here as there are not enough wild animal sanctuaries to close all the zoos at once and relocate the animals there, and you do not want to add more stress to the animals currently incarcerated. And what would such a phasing-out policy would look like? It should include the following:

  1. Set up a plan to abolish all zoos by a particular date
  2. Stop licensing new zoos and close those unlicensed.
  3. Ban the breeding of any animal in zoos
  4. Ban zoos from taking animals from the wild
  5. Ban zoos acquiring more animals except when directed by the authorities to look after confiscated or rescued animals (or from closing zoos)
  6. Close the smallest and worst zoos and relocate their animals to reputable wild animal sanctuaries
  7. Take over the administration and running of some zoos and transform them into temporary wild animal sanctuaries not open to the public and without any breeding allowed
  8. Improve the conditions of the remaining animals in the remaining zoos by giving them more space, privacy, and enrichment (as zoo animals die out there should be more space available to the remaining ones).
  9. Inspect all zoos properly and severely penalise any breach of legislation and regulations or any unduly delay of the phasing-out process
  10. Work in collaboration with animal protection organisations to help inspect zoos, relocate the animals, and rescue them if needed
  11. Once the last animal kept in the last zoo dies, pass legislation that bans all zoos in the future, and prevents the support and promotion of zoos still active in other jurisdictions.

However, above all, we should ensure that the current zoo operators are not leading this phasing out process as they would most likely try to continue profiting from animals and deceive the public into believing they are phasing out zoos as they asked, when they may not (as may be the case of some zoos that announced they would stop keeping “exotic” animals and only keep from now one “local” fauna, to ensure their business keeps going in places where most of the population is already calling for the abolition of zoos—such as in Argentina).

They may be zoo keepers who genuinely care about the animals they look after and they could well be converted into sanctuary carers (especially if they show how much they have changed and have become vegan, for instance), but I would not trust the zoo operators because of their reputation of deception and their history of exploitation of animals for profit.

I know them too well to trust them.

Jordi Casamitjana
“Originally from Catalonia, but resident in the UK for several decades, Jordi is a vegan zoologist and author, who has been involved in different aspects of animal protection for many years. In addition to scientific research, he has worked mostly as an undercover investigator, animal welfare consultant, and animal protection campaigner. He has been an ethical vegan since 2002, and in 2020 he secured the legal protection of all ethical vegans in Great Britain from discrimination in a landmark employment tribunal case that was discussed all over the world. He is also the author of the book, ‘Ethical Vegan: a personal and political journey to change the world’.