Episodic-Like Memory Stays Strong in Aging Cuttlefish

Cuttlefish can remember what, where, and when specific things happened—right up to their last few days of life, researchers at the University of Cambridge have found. This suggests that episodic-like memory does not decline with age in cuttlefish, unlike in humans. The results were published in the journal Proceedings of the Royal Society B. 

The team conducted memory tests on twenty-four common cuttlefish, Sepia officinalis. Half of these were 10-12 months old—not-quite adult and the other half were in old age at 22-24 months—equivalent to humans in their 90s. “Cuttlefish can remember what they ate, where and when, and use this to guide their feeding decisions in the future. What’s surprising is that they don’t lose this ability with age, despite showing other signs of aging like loss of muscle function and appetite,” said first author Alexandra Schnell. 

To conduct the experiment, the cuttlefish were first trained to approach a specific location in their tank marked with a black and white flag. Then they were trained to learn that two foods they commonly eat were available at specific flag-marked locations and after specific delays. At one spot, the flag was waved and a piece of king prawn, their less preferred food, was provided. Live grass shrimp, which they like more, was provided at a different spot where another flag was also waved—but only every three hours. This was repeated for four weeks.

Then the cuttlefishes’ recall of which food would be available, where, and when was tested. To make sure they hadn’t just learned a pattern, the two feeding locations were unique each day. All the cuttlefish regardless of age—watched which food first appeared at each flag and used that to work out which feeding spot was best at each subsequent flag-waving.