by University
of Cambridge
A European common cuttlefish, Sepia
officinalis. Credit: Pauline Billard
"It
was surprising to see how quickly the cuttlefish adapted
their eating behaviour—in only a few days they learned whether there was likely
to be shrimp in the evening or not. This is a very complex behaviour and is only
possible because they have a sophisticated brain," said Pauline Billard, a Ph.D.
student in the University of Cambridge's Department of Psychology and Unicaen,
France, and first author of the report.
Cuttlefish foraging behaviour can be described as either selective or
opportunistic. Observing the European common cuttlefish, Sepia officinalis, when
the researchers reliably provided one shrimp every evening, the cuttlefish
became more selective during the day and ate significantly fewer crabs.
But when they were provided with evening shrimp on a random basis, the
cuttlefish became opportunistic and ate more crabs during the day.
Random provision of evening shrimp meant that the cuttlefish could not predict
whether their favourite food would be available for dinner each day, so they
made sure they had enough to eat earlier in the day. When conditions changed,
the cuttlefish changed their foraging strategy to match.
The
researchers saw the animals quickly shift from one eating strategy to another
based on their experience. By learning and remembering patterns of food
availability, the cuttlefish optimise their foraging activity not only to
guarantee they eat enough—but also to make sure they eat more of the foods they
prefer.
Cuttlefish eat a wide range of food including crabs, fish and squid, depending
on what is available. Despite such a generalised diet, they show strong food preferences.
To test this, the researchers tested twenty-nine cuttlefish five times a day,
for five days, by putting crab and shrimp at an equal distance from the
cuttlefish at the same time and watching what they ate first. All showed a
preference for shrimp.
Animals must constantly adapt to changes in their environment in order to
survive. Cuttlefish hatch with a large central nervous system, which enables
them to learn from a young age. They are capable of remembering things that
happened in the past, and using this information to adjust their behaviour in
anticipation of the future.
Cuttlefish are a type of cephalopod. In evolutionary terms, cephalopods and
vertebrates diverged around 550 million years ago, yet they are remarkably
similar in the organisation of their nervous systems.
"This
flexible foraging strategy shows that cuttlefish can adapt quickly to changes in
their environment using previous
experience," said Professor Nicola Clayton in the University of Cambridge's
Department of Psychology, who led the study. "This discovery could provide a
valuable insight into the evolutionary origins of such complex cognitive
ability."
Explore further
3-D movies reveal how cuttlefish determine distance
when striking at prey
More
information: Cuttlefish show flexible and future-dependent foraging
cognition, Biology Letters, royalsocietypublishing.org/doi
… .1098/rsbl.2019.0743
Journal information: Biology
Letters Provided by University
of Cambridge
Source: PhysOrg URL:
https://phys.org/news/2020-02-cuttlefish-lunch-therell-shrimp-dinner.html