## Accessibility links

- Skip to content
- Skip to local navigation
- Accessibility Help

## Science & Environment

18 July 2013 Last updated at 17:13 GMT

### Share this page

- Delicious
- Digg
- Facebook
- reddit
- StumbleUpon
- Twitter
- Email
- Print

# Chimpanzees and orangutans remember distant past events

By Melissa Hogenboom Science reporter, BBC News
A study has shown for the first time that chimps and orangutans remembered events from three years earlier
Continue reading the main story

## Related Stories

- Apes may suffer 'mid-life crisis' Watch
- Chimpanzees behave 'like people'
- Scientists decode gorilla genome

Chimpanzees and orangutans were able to remember past events when presented with sensory reminders, a new study shows.

Both species found where a useful tool was hidden three years after performing a task only four times.

They were also able to recall a unique event two weeks later.

The team say their work, published in Current Biology, shows memory for past events is not unique to humans.

Chimps and orangutans were presented with two boxes in different rooms, one of which had useful tools, the other useless ones. In order to get a reward they had to successfully retrieve the useful tools.

Three years later, without witnessing them being hidden, they retrieved the useful tools correctly.

Instant recollection

It has been well established in humans that sensory cues like songs and smells can help transport our minds back to the past.

The team, led by Gema Martin-Ordas of Aarhus University, Denmark, used the same principle. They found that cues - keeping the experimental set up the same - triggered the apes' memories.

Continue reading the main story

## Clever apes

- Common chimpanzees (Pan troglodytes) are mankind's closest living relative and are thought to be the most intelligent non-human animal
- Chimpanzees are known to modify sticks, rocks and leaves into tools to help the gather food such as ants, nuts and honey
- Orangutans are also capable of learning to use "tools" such as sticks to gather termites. This knowledge is then passed down through the generations

- See an Orangutan learn about forest living
- Watch how wild chimpanzees use tools

They observed that 90% of the apes who experienced the event three years earlier found the tool in the correct location almost instantly.

"Our data, and other emerging evidence, keep challenging the idea of non-human animals being stuck in time," said Dr Martin-Ordas.

"We show not only that chimpanzees and orangutans remember events that happened two weeks or three years ago, but also that they can remember them even when they are not expecting to have to recall those events at a later time.

"What this shows is that the episodic memory system in humans is not as unique as we thought it was, as we share features with non-human primates."

This could mean the capacity to remember past event could have evolved before humans were present, she told BBC News.

"I think it's important to know who we are and what makes us unique. Learning about what other species can do gives us a more comprehensive picture about humans."

Conscious replay

Michael Corballis from the University of Auckland, New Zealand, who was not involved with the work, said the study moves us significantly closer to showing that chimpanzees and orangutans have human-like episodic memory "in defiance of what some of us have maintained".

But while humans can recall what, where and when something happened, the apes were missing the "when" component, he added.

"There is no indication that the animals remembered when the earlier event occurred. This is not to say the animals had no inkling of this, and in any case we humans are often hazy about the locations of events in time.

"My guess is that great apes, and perhaps even rats, have episodic memories similar to our own, probably less rich and detailed, but similar in essence."

The authors of the work note there is no way of telling whether or not the animals had a conscious recollection of these past events.

But Dr Corballis said this could be overly pessimistic, as previous studies of activity in the hippocampus of rats "do seem to provide evidence of conscious replay of event".

## More on This Story

### Related Stories

- Apes may suffer 'mid-life crisis' Watch
  20 NOVEMBER 2012, SCIENCE & ENVIRONMENT
- Chimpanzees behave 'like people'
  23 MAY 2012, NEWS
- Scientists decode gorilla genome
  07 MARCH 2012, SCIENCE & ENVIRONMENT
- Orangutans show talent for mime
  11 AUGUST 2010, SCIENCE & ENVIRONMENT

### Related Internet links

- Gema Martin-Ordas at Aarhus University
- Michael Corballis at the University of Auckland

The BBC is not responsible for the content of external Internet sites

### Share this page

- Delicious
- Digg
- Facebook
- reddit
- StumbleUpon
- Twitter
- Email
- Print

## More Science & Environment stories

RSS

- ### S Asia disunity foils flood warnings

  A lack of co-operation between South Asian countries is preventing timely flood warnings that could save lives during the Monsoon season.

- ### Early society 'not driven by war'

- ### Tax cut for shale gas firms planned

## Top Stories

- Detroit in largest US bankruptcy
- Australia to block boat people - PM
- Kremlin critic Navalny freed on bail
- OECD plan to prevent tax 'abuse'
- Boston suspect capture photos leaked

## Features & Analysis

- ### Life in transit

  A man who has spent four months living in an airport

- ### Bouncing back

  What baseball teaches you about the American way of life

- ### In pictures

  The dying art of mime in India

- ### 7 days' quiz

  What is annoying people in public toilets?

## Most Popular

### Shared

1. 1: Detroit in largest US bankruptcy
2. 2: Tax cut for shale gas firms planned
3. 3: Warning over cancer health issues
4. 4: Early society 'not driven by war'
5. 5: What is it like to live in an airport?

### Read

1. 1: Rowling to kill two in final book
2. 2: Detroit in largest US bankruptcy
3. 3: What is it like to live in an airport?
4. 4: Australia announces PNG asylum deal
5. 5: Boston accused 'manhunt photos' seen
6. 6: Rowling 'anger' over pseudonym leak
7. 7: UAE holds man over road attack video
8. 8: Early society 'not driven by war'
9. 9: Quiz of the week's news
10. 10: Wikipedia 'edit wars' revealed

### Video/Audio

1. 1: 'Tourism is dying in Egypt's Luxor' Watch
2. 2: Detroit files for bankruptcy Watch
3. 3: One-minute World News Watch
4. 4: How long will the heatwave last? Watch
5. 5: Snail facial anyone? Watch
6. 6: Cage: 'I'm a pretty boring guy' Watch
7. 7: Mars 'was similar to Earth' Watch
8. 8: Inside Yemen's 'torture camps' Watch
9. 9: The man behind the death mask Watch
10. 10: UAE holds man over road-attack video Watch

## BBC Future

### Reach inside your computer

3D tech allows you to "feel" digital worlds Read more...

## Programmes

- ### Talking Movies Watch

  A tale of revenge and extreme violence - Tom Brook reviews Only God Forgives

## BBC links

- - Mobile site
  - Terms of Use
  - About the BBC
- - Advertise With Us
  - Privacy
  - Accessibility Help
- - Ad Choices
  - Cookies
  - Contact the BBC
- - Parental Guidance

BBC © 2013 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.