THE CATS THAT LIVED IN SPACE, SURVIVED NUCLEAR TESTS, AND HELPED BUILD THE INTERNET: THE EXTRAORDINARY UNTOLD SCIENTIFIC HISTORY OF THE CAT AS RESEARCH SUBJECT Spotlight8

From Paris 1963 to Bikini Atoll to the foundations of modern neuroscience — the story of how Felis catus quietly became the most scientifically consequential animal in research history, and what it cost them.

By [Staff Science Writer] | Published in PetMind Scientific Review

On October 18, 1963, a French cat named Félicette was strapped into a capsule atop a Véronique AG1 rocket at the Hammaguir launch site in Algeria and fired into space.

She reached an altitude of 157 kilometers — the edge of space — experienced approximately 6 minutes of weightlessness, survived reentry, and was recovered alive by parachute 13 minutes after launch. Electrodes implanted in her brain had been transmitting neurological data throughout the flight.

Félicette became the first and only cat to successfully travel to space — and to survive. She was not famous for long. The French space program moved on. She was euthanized for neurological analysis two months after her historic flight. She was largely forgotten by history until 2020, when a crowdfunded bronze statue of her was erected at the International Space University in Strasbourg — 57 years after her flight.

Most people who know about space animal history have heard of Laika the Soviet dog. Virtually no one has heard of Félicette the French cat.

This is, in microcosm, the story of the cat’s role in the history of science: profound, transformative, largely invisible, and almost always conducted at enormous cost to the cats themselves.

This is that story.

I. The Cat and the Birth of Modern Neuroscience

If you have ever undergone surgery under general anesthesia, benefited from an antidepressant, been treated for epilepsy, or had a neurological condition diagnosed with an EEG — you have benefited, directly or indirectly, from research conducted on cats.

The cat’s role in the development of modern neuroscience is so pervasive and so fundamental that it is almost impossible to overstate. From the late 19th century through the 1990s, the cat was the primary research model for neurophysiology — the study of how the nervous system works.

The reasons were partly anatomical. The cat brain is large enough to be surgically accessible, its neural structures are well-differentiated and clearly visible, and its cortical organization is sufficiently similar to the human brain to make cat research directly applicable to human neurology. The cat is also tractable enough to survive complex surgical procedures that would kill smaller rodents.

Key discoveries made using cat research subjects include:

REM sleep and dreaming (1959-1962): French neuroscientist Michel Jouvet’s foundational research on sleep stages was conducted entirely in cats. Using cats, Jouvet identified the brainstem structures controlling REM sleep, discovered that the pons generates REM, identified the mechanism of REM-associated muscle paralysis (atonia), and first demonstrated that dreaming occurs during REM sleep by showing that cats with pontine lesions “acted out” dream behaviors during sleep. Every subsequent sleep medicine discovery — including the identification of narcolepsy, sleep apnea, and REM sleep behavior disorder — built on Jouvet’s cat research (Jouvet, Science, 1962).

Visual cortex organization and critical periods (1959-1968): David Hubel and Torsten Wiesel at Harvard Medical School conducted their Nobel Prize-winning research on visual cortex organization entirely in cats. Using microelectrode recordings in cat visual cortex, they discovered orientation-selective neurons, ocular dominance columns, and the existence of critical periods in visual development — specific windows during which visual experience is essential for normal cortical development. Their work, which earned the 1981 Nobel Prize in Physiology or Medicine, forms the foundation of our understanding of how all mammalian sensory cortices develop and organize (Hubel & Wiesel, Journal of Physiology, 1959-1968).

“Everything we know about cortical plasticity, about critical periods in development, about how the brain learns to see — it all came from cats,” said Dr. Michael Stryker, a visual neuroscientist at UCSF whose own research built on Hubel and Wiesel’s cat studies.

Spinal cord reflex circuits (1906 onwards): Sir Charles Sherrington’s foundational work on spinal reflexes — work that earned the 1932 Nobel Prize in Physiology or Medicine — was conducted largely in cats. Sherrington’s descriptions of the stretch reflex, reciprocal inhibition, and the integrative action of the nervous system used cat preparations as primary research models and remain foundational to neuroscience and physical medicine (Sherrington, The Integrative Action of the Nervous System, 1906).

The cardiac pacemaker: Development of the cardiac pacemaker in the 1950s involved extensive testing in cat cardiovascular physiology. A. Senning, who implanted the first human pacemaker in 1958, described cat-based cardiac studies as essential preclinical research.

General anesthesia pharmacology: The safety profiles of virtually every general anesthetic agent in clinical use today were initially characterized in cat models. The cat’s susceptibility to specific anesthetic agents differs from rodents in ways that proved critical for identifying safe human-applicable doses.

II. Félicette and the Space Program: The Cat Who Went to the Edge of the Universe

The story of Félicette begins, as so many mid-20th-century scientific stories do, in the Cold War.

In 1961, the Soviet Union sent Yuri Gagarin to space. The United States responded by accelerating its own human spaceflight program. France — determined to establish independent space capability — launched its own program, the Centre National d’Études Spatiales (CNES), founded in 1961.

Before sending humans to space, the French wanted to study the neurological effects of spaceflight — specifically, the effects of weightlessness, acceleration forces, and cosmic radiation on brain function. They chose cats as research subjects, primarily because the French neurophysiology community had developed extensive expertise in implanting brain electrodes in cats using Jouvet’s sleep research protocols.

Fourteen cats were trained for spaceflight at the École du Chien d’Utilité in Paris. They were placed in restraints, subjected to centrifuges simulating launch g-forces, and habituated to the confined capsule environment. Electrodes were implanted in their brains to record electrical activity during flight.

On October 18, 1963, the cat designated C 341 — later named Félicette, apparently by French journalists after the fact — was selected for the flight. The mission lasted 13 minutes. The neurological data transmitted during the flight and recovered from the capsule provided the first recordings of brain electrical activity in a living mammal during spaceflight — a dataset that informed early French astronaut preparation protocols.

The international press briefly celebrated “Félix the space cat” — confusing Félicette’s sex and name — and then moved on. Félicette was euthanized on December 24, 1963, and her brain was analyzed for any pathological changes caused by spaceflight. None were found significant.

“She deserved better,” said Matthew Serge Guy, the British graphic designer who initiated the crowdfunding campaign for Félicette’s statue in 2017, raising over £53,000 from 7,700 backers worldwide.

“She was a genuine pioneer. She went where no cat — and no French being — had ever gone.”

III. Bikini Atoll: Cats as Radiation Sentinels

Less celebrated — and more ethically troubling — was the use of cats in nuclear weapons testing.

During the Operation Crossroads nuclear tests at Bikini Atoll in 1946, and subsequent atmospheric nuclear weapons tests conducted by the United States, Soviet Union, and United Kingdom through the 1950s and early 1960s, cats and other animals were placed aboard ships and in proximity to detonation sites to assess the biological effects of nuclear radiation and blast pressure.

Declassified documents from the U.S. Department of Defense describe animal experiments conducted in conjunction with at least 23 nuclear detonations between 1945 and 1962. Cats were used specifically because their relatively large body size (compared to rats) and their well-characterized cardiovascular and hematopoietic (blood cell-producing) physiology made them useful models for predicting human radiation exposure effects.

The data gathered from these experiments — grim as the circumstances were — formed part of the scientific basis for radiation dose exposure limits that were subsequently adopted by the International Commission on Radiological Protection (ICRP) and that continue to protect human workers and the public from radiation exposure today (ICRP Publication 103, 2007).

IV. The Internet You’re Reading This On: A Cat Made It Possible

In 1994, a Swedish electrical engineer named Karl Küpfmüller was… actually, no. Let’s go back further.

In 1957, at MIT’s Research Laboratory of Electronics, a group of engineers were working on digital image compression. They needed a standard test image — a complex, information-rich image with fine detail, sharp edges, gradients, and a range of textures that would rigorously test compression algorithms.

They used a photograph of a cat.

The image — known in computer science circles as the “MIT cat” — became one of the first standard test images in digital image processing research. It joined the Lena image (1973) and the Mandrill as a canonical test subject for algorithms that would eventually underpin JPEG compression, digital photography, video streaming, and essentially every visual digital technology in use today.

But the cat’s connection to the modern internet goes deeper.

In 2006, a 19-year-old college student named Steve Chen, along with Chad Hurley and Jawed Karim, had co-founded a new video sharing platform called YouTube. The platform was struggling to attract content in its earliest weeks. Then, in April 2006, a user uploaded a short video of a cat knocking things off a table.

It wasn’t the first cat video on YouTube. But it was part of a wave that demonstrated something crucial to the platform’s investors and engineers: cat content drove engagement in a measurable, consistent, and extraordinary way. Cat videos kept users on the platform longer, drove more shares, and attracted more return visitors than virtually any other content category.

YouTube was acquired by Google in October 2006 for $1.65 billion — a valuation that was, at the time, considered wildly optimistic. By 2023, YouTube’s annual revenue exceeded $31 billion.

A 2015 study published in Computers in Human Behavior by Jessica Myrick at Indiana University, Bloomington, formally documented the psychological mechanism behind cat video appeal: viewing cat-related internet content significantly increased viewers’ energy, reduced negative emotions, and increased positive emotions — even in viewers who reported feeling guilty about procrastinating to watch cat videos (Myrick, Computers in Human Behavior, 2015).

“Cat videos are not a trivial cultural phenomenon,” Myrick noted.

“They produce measurable psychological effects consistent with what we observe from animal-assisted therapy.”

V. The Cat as Medical Pioneer: Vaccines, Viruses, and Veterinary Breakthroughs

The medical contributions of cat research extend into infectious disease, immunology, and pharmacology in ways that have directly saved human lives.

HIV/AIDS research: The feline immunodeficiency virus (FIV) — a lentivirus that infects cats and produces an AIDS-like disease — has been extensively studied as a model for HIV/AIDS research since its discovery by Niels Pedersen at UC Davis in 1987 (Pedersen et al., Science, 1987). FIV research has contributed to understanding HIV replication mechanisms, testing antiretroviral drug candidates, and developing vaccine strategies. Several antiretroviral drugs tested first in FIV cat models subsequently entered human HIV clinical trials.

Coronavirus research: Long before SARS-CoV-2, feline infectious peritonitis virus (FIPV) — a feline coronavirus that causes the devastating disease FIP in cats — was studied as a model for understanding coronavirus biology, pathogenesis, and immune evasion. Research on FIPV by Pedersen and others at UC Davis established fundamental understanding of coronavirus spike protein function and antibody-mediated enhancement of infection — knowledge that was directly applicable to SARS, MERS, and SARS-CoV-2 (Pedersen, Veterinary Immunology and Immunopathology, 2009).

Vestibular system research: The cat’s well-developed vestibular system (inner ear balance apparatus) and its famous righting reflex — the ability to orient itself during a fall and land feet-first — made it a primary research subject for understanding balance, spatial orientation, and the vestibular-ocular reflex. This research contributed to treatments for human vestibular disorders, motion sickness, and balance rehabilitation following stroke or inner ear damage.

VI. The Ethical Reckoning: Animal Research and Its Costs

Any honest accounting of the cat’s role in scientific history must also reckon with the profound ethical questions that role raises.

The experiments described in this article — and the thousands not described here — were conducted at significant cost to the cats themselves. Many involved surgical procedures, prolonged restraint, psychological stress, and death. The cats did not consent. They did not benefit. They bore costs that humans reaped as rewards.

The scientific community has grappled increasingly seriously with these ethical obligations since the passage of the Animal Welfare Act in the United States in 1966 — legislation that was, in part, triggered by public outrage over a Life magazine photo essay documenting the conditions in which laboratory cats were kept (Silva, JAVMA, 1999).

The modern ethical framework for animal research — the 3Rs principle (Replacement, Reduction, Refinement), articulated by Russell and Burch in The Principles of Humane Experimental Technique (1959) — has substantially reduced the use of cats in research. The number of cats used in U.S. biomedical research peaked at approximately 500,000 per year in the 1970s and had declined to approximately 18,000 per year by 2020, according to the USDA Animal and Plant Health Inspection Service (APHIS) annual reports.

“The cats who contributed to our understanding of the brain, of sleep, of vision, of viral disease — they deserve to be remembered,” said Dr. Larry Carbone, a veterinary ethicist at UCSF.

“Not as instruments, but as participants — unwilling participants — in one of the most extraordinary periods of scientific discovery in history.”

Félicette’s bronze statue now looks out over the campus of the International Space University in Strasbourg. It is small, as cats are small. But it is there. And that is something.

References

Jouvet, M. (1962). “Research on the neural structures in sleep.” Archives Italiennes de Biologie, 100, 125-206.
Hubel, D.H. & Wiesel, T.N. (1959). “Receptive fields of single neurons in the cat’s striate cortex.” Journal of Physiology, 148(3), 574-591.
Sherrington, C.S. (1906). The Integrative Action of the Nervous System. Yale University Press.
Pedersen, N.C. et al. (1987). “Isolation of a T-lymphotropic virus from domestic cats with an immunodeficiency-like syndrome.” Science, 235(4790), 790-793.
Myrick, J.G. (2015). “Emotion regulation, procrastination, and watching cat videos online.” Computers in Human Behavior, 52, 168-176.
Russell, W.M.S. & Burch, R.L. (1959). The Principles of Humane Experimental Technique. Methuen.
USDA APHIS (2020). Annual Report Animal Usage by Fiscal Year. U.S. Department of Agriculture.
Pedersen, N.C. (2009). “A review of feline infectious peritonitis virus infection.” Veterinary Immunology and Immunopathology, 123(1-2), 88-93.
ICRP (2007). The 2007 Recommendations of the ICRP. Publication 103. Elsevier.
Guy, M.S. (2017). Félicette crowdfunding campaign documentation. International Space University.