Justice for our animal kin, Part 1 of 2: Landmark animal rights cases that changed the law

People say that “justice is blind,” referring to its supposed impartiality, but the law has never been neutral. It reflects the values of the societies that create it, and for too long, those values have excluded or harmed our fellow animals.

This exclusion hasn’t just kept them invisible; it has enabled some of the worst abuses to go unpunished. Lives lived in confinement, cruelty justified as tradition, suffering made legal.

Now, a growing movement of legal professionals, activists, and everyday citizens is working to change that. They’re challenging the idea that our fellow animals are merely property by calling on legal systems to recognise them as sentient beings worthy of rights.

In this two-part blog series, we’ll explore how animal law is evolving.

What are the legal cases that have shaped the fight for animal rights? Which recent and ongoing lawsuits are pushing the boundaries of what’s possible? And who are the people behind this movement for justice?

What is Animal Law and why does it matter?

Wikipedia defines Animal Law as “a combination of statutory and case law in which the nature – legal, social or biological – of nonhuman animals is an important factor”. 

It covers everything from cruelty cases and welfare standards to environmental law and efforts to recognise members of our animal kin as legal persons. 

While many countries have laws against causing unnecessary suffering, those laws often fall far short of offering true protection. 

This is because our fellow animals are no different, legally speaking, from a chair or a car. They appear in law as property, as objects of legal duties and rights rather than subjects of them, i.e. things acted upon, rather than individuals whose own interests are recognised and protected. 

There are some exceptions, in that animals have occasionally appeared as legal subjects throughout history – though almost never to their benefit! 

In medieval Europe, for example, some farmed animals were tried and sentenced for so-called crimes like theft or destruction of property. 

It’s striking that animals have been granted legal personhood when it meant they could be punished, but never when it might protect their wellbeing. They were treated as subjects of the law when blame or death was on the table, not when compassion or justice might have been.

These insights raise important questions about who gets to count in the eyes of the law and why? 

A brief history of significant legal landmarks

Early cases

While the modern animal law movement gained real momentum in the late 20th century, there are earlier legal developments worth acknowledging. 

The Cruel Treatment of Cattle Act (better known as “Martin’s Act”) was passed in 1822 in the UK and marked the first time it became a punishable offence to abuse certain animals. It laid the groundwork for the formation of the RSPCA two years later and was the first known piece of animal welfare legislation in the world. 

Although Martin’s Act didn’t challenge animal agriculture in any way, it put into law that farmed animals experience pain, fear, and suffering.

Another early case (Stephens v. State, 1884) took place in the US. The Defendant, Dave Stephens, faced charges of cruelty after killing several pigs that kept breaking into his field and damaging his crops. At his trial, the lower court refused to let the jury consider whether his actions were necessary.

On appeal, the Mississippi Supreme Court said the jury should have been allowed to consider Stephens’ motives. Although the court ultimately ruled in Stephens’ favour, the judge made a striking moral statement: “Animals whose lives are devoted to our use and pleasure, and which are capable perhaps of feeling as great physical pain or pleasure as ourselves, deserve, for these considerations alone, kindly treatment”.

It wasn’t an animal rights win, but it was an early sign that animal suffering might deserve legal consideration, even when the animals in question were seen as property.

While these early cases were more concerned with ideas of social decency than animal freedom, they did plant a vital seed: that our fellow animals could, in some circumstances, be recognised as victims in the eyes of the law.

Landmark victories from the late 20th century onwards

We can’t cover the whole history of animal law in one blog, but there are some key cases that we want to highlight:

The Silver Spring Monkeys (USA, 1981) 

This case arguably lit the fuse for the modern animal rights movement in the United States.

In 1981, a young undercover investigator, Alex Pacheco, who would go on to co-found PETA, volunteered at the Institute for Behavioural Research in Maryland. What he found inside was horrifying. 

Seventeen macaque monkeys were being used in experiments by a neurologist called Edward Taub, who had deliberately severed the nerves in their limbs to study “learned disuse.” With no sensation in their arms or hands, many of the monkeys began to self-mutilate, unknowingly biting or injuring themselves. Their wounds were left untreated. They were kept in squalid cages without proper veterinary care, stimulation, enrichment, or even basic cleanliness.

Pacheco documented everything. His photographs and reports led to a police raid on the lab, marking the first time that animals were confiscated by federal authorities due to welfare violations. 

The case moved through two trials and an appeal. Taub was initially found guilty on six counts of animal cruelty, but an appeal court later overturned all the charges. Despite offers from two sanctuaries to rehome the monkeys, the authorities returned them to government labs. Eventually, the monkeys were euthanised, but not before being further used as research subjects.

Their suffering was not forgotten. The case became national news. Celebrities and politicians spoke out, and public pressure grew. It marked the formal founding of PETA and led to lasting changes in US law, including amendments to the Animal Welfare Act that required improved standards of care and expanded oversight of laboratory conditions.

The Silver Spring monkeys didn’t live to see the world change, but their story helped shift public awareness and legal accountability in profound ways. Not least, it made people aware that suffering was happening behind closed laboratory doors.

McLibel Trial (UK, 1990s)

The McLibel case was one of the longest trials in English legal history. It involved two environmental and animal rights activists, Helen Steel and David Morris, who distributed leaflets criticising McDonald’s practices. 

Sued for libel, Steel and Morris represented themselves in court and brought evidence on animal cruelty, deforestation, and health harms into public view. In a 1,000-page judgement, Mr Justice Roger Bell found some of the leaflet’s claims to be “false and libellous”. However, one of his rulings was that McDonalds were “culpably responsible” in the infliction of unnecessary cruelty to animals.

The trial became a symbol of the imbalance of power between corporations and individuals and highlighted the ethical issues at the heart of industrialised animal exploitation. The case also led to a successful challenge at the European Court of Human Rights, where it was ruled that Steel and Morris’ right to a fair trial had been violated.

Tommy and Kiko the Chimpanzees (USA, 2010s) 

Two cases brought by the Nonhuman Rights Project (NHRP) argued that chimpanzees Kiko and Tommy (both now deceased) should be recognised as legal persons with a right to bodily liberty. Indeed, Tommy was the NHRPs first client.

Using the writ of habeas corpus (typically reserved for humans who have been wrongfully imprisoned and of great importance to immigration rights), the cases sought to free the chimpanzees from lifelong confinement in substandard conditions.

Although the courts ultimately rejected the argument that Tommy and Kiko should be recognised as legal persons, their cases were landmark moments because they helped lay the legal and cultural groundwork for future litigation. 

Through powerful dissenting opinions, widespread media coverage, and growing public empathy, these cases forced courts and society alike to confront uncomfortable truths: that chimpanzees can suffer mentally, emotionally, and physically in captivity, and that denying their liberty causes deep harm.

Many people who followed Tommy and Kiko’s stories recognised this intuitively. They could see that these beings were not property, but individuals who were self-aware, social, and deeply affected by confinement. 

Yet while public awareness moved forward, the law remained stuck. In the eyes of the legal system, Tommy and Kiko were still objects, not subjects, of the law. Their right to bodily liberty was never recognised. But the cracks had begun to show, and those cracks have since become the starting points for new legal challenges that seek to centre the interests of our fellow animals more fully.

Whale Wars in the International Court of Justice (ICJ, 2014)

Australia took Japan to the ICJ over its so-called “scientific whaling” programme in the Southern Ocean. The court ruled that Japan’s activities were not genuinely scientific and ordered them to cease.

This was a landmark case in using international law to hold a nation accountable for its treatment of natural-living animals, and it underscored the potential for global cooperation on animal protection issues.

Animal Welfare Board of India v. A. Nagaraja & Others (India, 2014)

This landmark decision by the Indian Supreme Court effectively banned the bull-taming sport of Jallikattu and similar events involving cruelty to our animal kin. 

The court held that these practices violated the Prevention of Cruelty to Animals Act 1960 and contravened the constitutional duty of citizens to show compassion toward all living creatures under Article 51A(g) of the Constitution of India. 

The ruling was notable for its explicit recognition of nonhuman animals as sentient beings capable of suffering and deserving of constitutional protection. The judgement specifically highlighted that every living being present on this earth holds a right to live their life with dignity and respect. 

It also incorporated the internationally recognised ‘five freedoms’ framework for animal welfare and asserted that our animal kin have intrinsic value beyond their utility to humans. 

While subsequent legislation reinstated Jallikattu in certain states, the 2014 judgment remains a pivotal moment in Indian animal law and a strong judicial affirmation of animals’ moral and legal standing.

Recent and ongoing cases pushing boundaries

The early cases above, and others like them, helped to define the landscape of modern animal law, highlighting its limitations, but also its potential. 

Each one broke new ground by questioning the legitimacy of treating our fellow animals purely as property or resources, and by pushing legal systems to acknowledge that animals across all species have interests that matter in and of themselves.

These cases paved the way for some of the recent and ongoing cases that are pushing the boundaries of how our fellow animals exist within the scope of the law. 

Happy the Elephant (USA, 2022)

Happy is a solitary elephant at the Bronx Zoo. She was captured as a baby in Thailand in the 1970s and has spent approximately 50 years in captivity. Since 2006, she has lived alone without a single companion. Happy is the first elephant to “pass” the mirror self-recognition test, which many view as an indicator of self-awareness. 

In 2018, the Nonhuman Rights Project filed a habeas corpus petition arguing that Happy was being unlawfully confined. 

Although the court ultimately ruled against granting her legal personhood, one dissenting judge publicly stated that: “[Happy’s imprisonment is] harmful, not because it violates any particular regulation or statute relating to the care of elephants, but because an autonomous creature such as Happy suffers harm by the mere fact that her bodily liberty has been severely – and unjustifiably – curtailed.” 

It was a signal that the legal tide is beginning to shift. The Nonhuman Rights Project continues to campaign for Happy’s release to a sanctuary, as well as the release of a number of other elephants who are currently captive in zoos.

Estrellita the Woolly Monkey (Ecuador, 2022) 

Estrellita was a woolly monkey who had been kept as a companion animal by her carer for 18 years, having been taken from her natural habitat illegally. When authorities discovered this, she was seized and placed in a zoo, where she sadly died within a month. 

Not knowing that Estrellita was already dead, her carer filed a habeas corpus petition arguing that the seizure violated Estrellita’s rights under Ecuador’s constitution.

In a groundbreaking ruling, Ecuador’s Constitutional Court not only accepted the habeas corpus claim, but went further. It ruled that free-living animals are subjects of legal rights under the country’s constitutional recognition of the Rights of Nature. This made Estrellita’s case the first time a court had explicitly recognised the individual constitutional rights of someone who wasn’t human.

The court concluded that Estrellita’s rights had been violated, both when she was taken from her natural home and again when she was removed from the only home she had known for nearly two decades. 

This case stands in striking contrast to the US ruling in Happy the elephant’s case, where personhood was denied despite widespread recognition of Happy’s autonomy and sentience. 

Estrellita’s case is a powerful example of how legal systems can evolve to reflect ethical responsibility, not just to ecosystems, but to individual animal lives. It’s one of the first legal decisions in the world to explicitly grant an individual animal constitutional protections.

Ag-Gag Law Challenges (USA, ongoing) 

Several US states have passed so-called “ag-gag” laws that criminalise undercover investigations on farms. Animal advocates have challenged these laws in court on the grounds that they violate free speech and the public’s right to know. 

In some states, courts have ruled these laws unconstitutional, which is a big win for transparency and animal protection. In other states, these “ag-gag” laws continue.

This is a complex legal battleground because it challenges First Amendment Rights in the US (and this is usually the grounds on which ag-gag laws are overturned), and has repercussions for food safety, workers’ rights, and more. Sentient Media offers a more detailed breakdown of the big issues.

Wildlife and Cull Cases (UK, ongoing) 

Wildlife protection groups in the UK continue to challenge the badger cull and the enforcement of the Hunting Act, arguing that the government’s decisions are based on flawed science or legal loopholes. These cases often shine a light on how state-sanctioned killing is justified, as well as how it can be contested.

Factory Farming Lawsuits (Global) 

In Australia, the USA, and parts of Europe, legal challenges are being brought against large-scale animal farming operations, not only on grounds of cruelty, but also due to their environmental and public health consequences. 

One example is the UK-based campaign Scrap Factory Farming, which brought legal action against the UK government for failing to consider the risks of intensive animal agriculture in relation to future pandemics, antimicrobial resistance, and climate change. 

The court dismissed the case, but the campaign gained public attention and highlighted how human health is intrinsically linked to health of other species.

This is the focus of many animal law campaigns centred on animal agriculture. Experts recognise that courts have been reluctant to affirm the legal rights of our fellow animals because it would open the floodgates to litigation and challenge the entire food system. 

Instead, advocates are focusing on the human costs of factory farming, with an emphasis on public health to create change (World Animal Protection discusses the big issues in its report, The Hidden Health Impacts on Industrial Livestock Systems). The hope is that this may open a door for future legal reforms that centre on the exploited animals themselves.

Other efforts include legal complaints in the EU over welfare breaches in live animal transport and US lawsuits challenging the conditions under which farmed animals live and die. 

These cases are beginning to weave animal protection into broader frameworks of justice.

Why these cases matter

Each case might seem like a drop in the ocean, especially when the system is so slow to change, but they matter. They lay the groundwork for new ways of thinking, test the edges of existing laws, and set new precedents.

They also challenge us to ask whether we’re truly offering the equal consideration of interests that blind justice demands.

Many of these cases centre around the core legal question: is a sentient being a someone or a something? If a non-verbal human can have rights and legal recognition, why not a self-aware elephant?

This is why cases like Happy’s matter. They force the legal system, and the public, to grapple with the moral weight of these contradictions.

Coming up next…

In Part 2, we’ll introduce some of the lawyers, organisations, and activists behind these battles. From courtroom pioneers to policy strategists, these are the people helping build a legal system that recognises the dignity and value of our animal kin.