Gertrude, the Neuralink pig

She stood on the stool. The graph spiked. Twenty million people watched.

28 August 2020 · Fremont, California

Gertrude

Elon Musk put a coin-sized computer in this pig's skull, wired it to the part of her brain that runs her snout, and put her on a livestream. She rooted around in the straw looking for food. The machine listened. This is her file.

The pig

Gertrude had been carrying the implant for about two months when Musk brought her out.

She was not performing. That was the entire point of her. She wandered her pen, nosed through straw, ate off a stool, and every time her snout touched something a line on a screen behind her jumped and the room heard a beep. The device in her head was reading the part of her brain that handles her nose, and it was reading it in real time, out loud, to an audience.

"A Fitbit in your skull with tiny wires."

Elon Musk, describing the implant, 28 August 2020

Musk called the segment the three little pigs demo. Joyce had no implant. Gertrude had hers. Dorothy had been given one and had it taken back out, brought on stage to prove the surgery could be undone. All three, he said, were fine.

"Healthy, happy and indistinguishable from a normal pig."

Elon Musk, on the implanted pigs

The tape

Neuralink put the whole thing on YouTube and it is still there. If you only watch one, watch the supercut.

The whole presentation in 14 minutes. CNET's supercut. Gertrude and the other pigs come out in the back half.
The original, unabridged. "Neuralink Progress Update, Summer 2020", posted by Neuralink on the day. The holding card above is the real one, the screen the audience sat staring at before he walked out.
Eight months later. Pager, a macaque with a device in each hemisphere, plays Pong with his mind. Roughly six million views.

The pen cards

The press reported three pigs. The pens say otherwise.

Someone in the audience photographed the enclosures that afternoon. The name placards were still clipped to the rails, each with a portrait and a short biography. Enlarged, four names are legible.

Enlarged detail of four name placards on the pen rails, each with a pig's portrait. The names read Joyce, Konstanze, Gertrude and Harriet.
  • JOYCE
  • KONSTANZE
  • GERTRUDE
  • HARRIET

Konstanze and Harriet appear in none of the contemporaneous coverage reviewed here. Dorothy has no placard in this frame.

Nothing was hidden. The demo was a staged segment and the segment used three animals. The room held more of them, and a stranger with a phone got their names. It is written down here because it is written down nowhere else.

Close enlargement of Gertrude's pen placard, showing her name and an oval portrait of a ginger pig.

Gertrude's own card, pulled from the same frame. Her portrait, her name, her pen. The biography under it is too small to read at the resolution of the source, so whatever it said about her is gone.

Musk

He spent the presentation doing what he does, which is to make something genuinely difficult sound like a consumer product and then say a thing he cannot possibly mean and let the room decide.

"I could have a Neuralink right now and you wouldn't know. Maybe I do."

Elon Musk, 28 August 2020

He was selling a future where the implant is elective and routine. Four years later a man who cannot move his arms was playing chess with it. Two years before that, the animal programme behind it was under federal investigation. Both of those are downstream of the afternoon Gertrude spent looking for food on camera.

Timeline

  1. 2016

    Neuralink is incorporated. Its existence is reported publicly in March 2017.

    Contrary Research · Built In

  2. 16 Jul 2019

    The company comes out of stealth in San Francisco, showing the N1 sensor and the surgical robot that threads it into tissue. Animal testing is disclosed.

    Built In · event photography by Steve Jurvetson, dated

  3. 28 Aug 2020

    The three little pigs demo. Gertrude, roughly two months post-implant, sets the neural readout spiking as she roots through straw and eats from a stool. Musk calls the device, about 23mm across, a Fitbit in your skull with tiny wires.

    CNN · CNBC · NBC · GeekWire

  4. Apr 2021

    Pager, a nine-year-old macaque with a device in each hemisphere, plays Pong on neural activity alone. The video reaches roughly six million views.

    PCRM · CBS News

  5. May 2021

    The Physicians Committee for Responsible Medicine sues for the UC Davis records. It eventually pries loose more than 600 pages: use protocols, health records, surgical logs, necropsies.

    PCRM, original records

  6. 2021

    In one study 25 of 60 pigs receive devices of the wrong size. A scientist warns the mistake would be a red flag to FDA reviewers. The experiment is run again with 36 sheep. Every animal is killed afterward.

    Reuters, via Fortune

  7. Feb 2022

    PCRM files a USDA complaint alleging chronic post-surgical infections, psychological distress and extreme suffering. Its review of the UC Davis records concludes 15 of 23 monkeys died or were euthanised. One necropsy notes internal bleeding and remnant electrode threads. BioGlue, unapproved for that use, is said to have reached at least two animals and caused damage. Neuralink disputed the cruelty framing.

    PCRM · CBS News · Fortune

  8. Dec 2022

    Reuters reports roughly 1,500 animals dead in testing since 2018, among them more than 280 sheep, pigs and monkeys, using the company's own estimates. The USDA Inspector General opens an investigation at a federal prosecutor's request into possible Animal Welfare Act violations. Twenty current and former staff describe an environment that produced careless mistakes.

    Washington Post · Fierce Biotech · E&T

  9. May 2023

    The FDA clears the first in-human trial, the PRIME study.

    Built In · bionic-vision.org

  10. 28 Jan 2024

    Noland Arbaugh, quadriplegic since 2016, receives the N1 implant and becomes the first human to carry one.

    Wikipedia

  11. 2024

    Some of Arbaugh's threads retract and cursor control degrades. The team recovers most of the function in software rather than reopening his skull. He plays Civilization VI and online chess for stretches of up to eight hours.

    The Week · TechTimes

  12. 2026

    Arbaugh closes the Robotics Summit in Boston by moving physical chess pieces with his thoughts. More than twenty people are enrolled in the study across four countries.

    The Robot Report · TechTimes

The ledger

Every figure carries its source. The two contested ones say who reported them instead of pretending to be settled.

FigureValueAttributed to
Pigs named on the pen cards4Photo, 28 Aug 2020
Pigs in the staged segment3Reporting
Time Gertrude carried the implant~2 monthsCNN, CNBC
Implant diameter~23 mmCNBC
Animals dead in testing since 2018~1,500Company est., via Reuters
Sheep, pigs and monkeys among them280+Reuters
Experiments identified as botched4Reuters
Animals in those experiments86 pigs, 2 monkeysReuters
Pigs given the wrong size device25 of 60Reuters
Sheep killed in the repeat run36Reuters
Monkeys used at UC Davis23PCRM
Of those, died or euthanised15PCRM review, UC Davis records
Pages released by the records suit600+PCRM
Views on the Pager video~6,000,000PCRM
First human implant28 Jan 2024Wikipedia
Arbaugh's longest sessionsup to 8 hoursThe Week

The machine that did it

Neuralink's surgical robot on display at the 2020 demonstration, a tall pale machine standing behind a barrier.
The surgical robot, photographed at the same venue that evening. Leijurv, CC BY-SA 4.0.

It threads the electrodes into cortical tissue while dodging the blood vessels on the surface of the brain. The filaments are far too fine to be placed by a human hand, which is why the robot has to exist at all. It is also why the pigs had to exist. A machine built for a human skull has to be proven on something first, and the something was Gertrude.

What she bought

Gertrude was a step toward a person, and the person is real.

Noland Arbaugh has been quadriplegic since 2016. He took the implant in January 2024 and moved a cursor with intention alone. When his threads pulled back and control started failing, the team got most of it back in software instead of opening his head again.

He plays Civilization VI. He plays chess online for eight hours at a go. In 2026 he closed a robotics conference by moving real pieces on a real board with his thoughts, and twenty-odd other people are now carrying the same device in four countries.

Both halves of this page are true at the same time. The ledger happened and so did Arbaugh. Anyone telling you one erases the other wants something from you.

Glossary

N1
The implant. A sealed unit about 23mm across, dropped into a piece of skull removed to make room for it.
Threads
The flexible filaments that carry the electrodes into tissue. Too fine to place by hand. They can retract, which is what happened to Arbaugh.
The Link
Neuralink's own name for the implanted system.
BioGlue
A surgical adhesive. PCRM's records indicate it was used at UC Davis outside its approved application and damaged at least two animals.
PRIME
Precise Robotically Implanted Brain-Computer Interface. The human study the FDA cleared in May 2023.
Necropsy
The post-mortem on an animal. These reports are where several numbers in the ledger come from.