Antennular Gaze
Do hermit crabs pay attention?
How can we monitor attention and shifts of attention in hermit crabs and other animals that don’t rely on vision or have obvious shifts in gaze?
What impacts a crab’s ability to pay attention, and how can we tell?
Yes! Hermit crabs pay attention to different environmental stimuli.
They also change patterns of attention in response to changes in their vulnerability.
We came up with a novel method to examine attention in hermit crabs and other crustaceans. By observing the antennules (the two appendages between the eyestalks in the centre of the hermit crab’s ‘face’), we can observe shifts of attention in this species. This helps us understand what sorts of things affect crab attention. It will also help us to investigate other questions about crustacean cognition in the future.
Antennule shift in the common hermit crab P. bernhardus. This is part of the video footage from our first experiment examining attention in crustaceans. In this experiment, we added a stimulus to the water a crab was in and watched for a change in the direction its antennules were flicking to see if the crab shifted attention in response to the stimulus. We also examined how vulnerability affects attention, crab vigilance and the value of different types of information (a.k.a., signal salience). Finally, we looked to see if crabs might show evidence that they can control attention if needed (for example, if predators are about). The attentional shift happens quickly after the cue is added to the water. In this video, we first show the process in real-time, then slowed to 240 frames per second so that you can clearly see what happens when a crab shifts its antennular ‘gaze’, demonstrating a shift of attention. Enjoy!