What did Koko the gorilla say about death?

When asked where gorillas go when they die, Koko signed "Comfortable hole, bye," which many interpret as her understanding of burial and farewell.

Could Koko the gorilla really understand sign language?

Koko learned over 1,000 signs in modified American Sign Language and understood about 2,000 spoken English words, though scientists debate how deeply she comprehended abstract concepts.

How did Koko react when her cat died?

When told her kitten All Ball was killed, Koko signed "Bad, sad, bad" and "Frown, cry, frown," and staff reported hearing sounds similar to human crying.

When did Koko the gorilla die?

Koko died peacefully in her sleep on June 19, 2018, at the age of 46.

Who taught Koko sign language?

Dr. Francine "Penny" Patterson began teaching Koko modified American Sign Language in 1972 when Koko was just one year old.

Koko the Gorilla's Response About Death

In a quiet moment that would later captivate millions, a researcher posed an impossible question to a 230-pound western lowland gorilla: Where do gorillas go when they die?

Koko paused. Then her massive hands moved deliberately through the air, forming signs she'd learned over decades of training. Her answer: "Comfortable hole, bye."

The Gorilla Who Changed Everything

Koko wasn't just any gorilla. Born at the San Francisco Zoo in 1971, she became the centerpiece of one of the longest-running experiments in interspecies communication. Under the guidance of Dr. Francine "Penny" Patterson, Koko learned a modified version of American Sign Language starting at age one.

Over her lifetime, Koko reportedly mastered over 1,000 signs and understood approximately 2,000 words of spoken English. She named her own pets, expressed preferences, told jokes, and—apparently—contemplated mortality.

What Did She Actually Mean?

Interpreting Koko's response requires some unpacking. The signs she used have been translated various ways:

"Comfortable" – suggesting peace or ease
"Hole" – possibly referring to a grave or the ground
"Bye" – a farewell, departure, or ending

Whether Koko truly grasped the concept of death in any philosophical sense remains debated among scientists. Critics point out that her handlers often interpreted her signs liberally, potentially reading meaning into ambiguous gestures.

But supporters argue that's missing the point. Even if Koko's understanding was imperfect, her response suggests something—an awareness of endings, of goodbyes, of bodies returning to earth.

Koko's Encounters With Loss

This wasn't Koko's only brush with mortality. In 1984, her beloved kitten All Ball was killed by a car. When told the news, Koko signed "Bad, sad, bad" and "Frown, cry, frown." Staff reported hearing her make sounds similar to human weeping.

She later adopted other cats, but reportedly asked about All Ball for years afterward. These responses fueled arguments that great apes possess emotional depth far beyond what science had traditionally acknowledged.

A Legacy Beyond Signs

Koko died in her sleep on June 19, 2018, at age 46. The Gorilla Foundation announced her passing with a statement noting she had "touched the lives of millions."

Her answer about death—"Comfortable hole, bye"—endures as one of the most haunting moments in the history of animal cognition research. It doesn't matter whether she fully understood the question. What matters is that she answered it at all, offering humans a tiny window into a mind we're still struggling to comprehend.

Perhaps she was just stringing together signs she knew. Or perhaps, in her own way, she understood exactly what she was saying.