Cuttlefish, often called the “chameleons of the sea,” are masters of camouflage. New research suggests these cephalopods may have another trick up their sleeve (or rather, tentacle): waving. This previously unobserved behavior opens exciting possibilities for understanding cuttlefish intelligence and communication. The preprint study, available on bioRxiv, details how these fascinating creatures use specific arm movements to potentially signal each other.
This groundbreaking research focuses on four distinct arm movements observed in two cuttlefish species, Sepia officinalis and Sepia bandensis. Researchers recorded these movements and played them back to other cuttlefish, who responded by waving back. The team even played flipped versions of the recordings, finding that cuttlefish were more likely to wave in response to upright videos. These four distinct signs have been labeled “up,” “side,” “roll,” and “crown.”
While the exact meaning of these tentacle waves remains a mystery, several theories exist. Researchers suggest they could be dominance displays, as other cuttlefish tended to retreat after observing a wave. Courtship displays are another possibility, though the signs were also seen in juveniles who aren’t yet sexually mature. The waves could also be defensive signals or expressions of internal states like mood. The research team suggests these signs might be symbolic, carrying different meanings depending on the context.
Intriguingly, the research hints at more than just visual communication. The arm waves create mechanical disturbances in the water, raising the possibility that cuttlefish might also perceive these signals through mechanoreception, essentially feeling the waves. Preliminary experiments support this hypothesis, suggesting these arm waves could be multimodal signals involving both vision and mechanoreception.
This discovery adds another layer to our understanding of cuttlefish intelligence. Previous research has shown these animals can exhibit future planning, a cognitive ability once thought exclusive to mammals and birds. They demonstrate the capacity to delay gratification for a larger reward, showcasing impressive cognitive skills.
The research team, led by Sophie Cohen-Bodénès from the Perceptual Systems Laboratory at the École Normale Supérieure (ENS) in France, believes machine learning could further unlock the secrets of cuttlefish communication. By applying algorithms to similar data, researchers hope to decipher the nuanced relationships between different arm signals and the stimuli that trigger them. Similar techniques have been successfully used to analyze sperm whale clicks, revealing intricate patterns of communication.
This latest discovery of tentacle waving emphasizes the complexity of cuttlefish behavior and communication. While much remains unknown, it’s clear these intelligent cephalopods have more to teach us about the diverse world of animal intelligence.
