Wednesday, May 16, 2007

Fascination of the Cetacean Cognition

Caribbean and Florida adventures offer several amazing encounters to interact with dolphins whose cognitive abilities excel the event. However, a new perspective on cetacean brains claimed that the cognition of cetaceans is merely a complexity associated with an increase in thermogenic neural cells as a result of climatic cooling in Eocene-Oligocene era. Nevertheless, countless laboratory exercises and research on communication, behavior, and social structures confirms that cognition is the principal factor of cetacean brain complexity, as reviewed in the latest issue of PLoS Biology.

Substantial evidence indicates cochlear and cortical modifications—attributed to the echolocation—within cetaceans’ brains around this Eocene-Oligocene transition. Contrary to the controversial report, cetacean body size became smaller during the Eocene-Oligocene transition. And with it a new dynamic altered the predation order of early cetaceans that may have contributed to behavioral changes. Independent cortical development occurred during the divergence of primates and cetaceans, yet convergent evolution is evident in many of the similar social and behavioral traits; especially limbic associations such as intuition, social awareness, and decision-making. An abundance of glial cells—crucial for axonal myelin— in the cetacean neocortex represents white matter that is exclusive to humans and cetaceans.

Many studies of bottle-nose dolphins in particular reveal cetacean understanding of self recognition, manipulation of mechanisms, and precision and memory of symbols and patterns. Cetacean dialect also has the capacity for advanced sound and recognition, discernment, and imitation as evidence for social learning in cognition. Bottle-nosed dolphins demonstrate an ability to communicate in conveying directional information (i.e. target exercises) and comprehending human gestures and pointing in interactions. Furthermore, cultural aspects such as ‘alliances within alliances’—a social behavior even rare to humans—are continually being researched within cetacean communities. Studies have proven evidence of meaningful relationships and cultural acquistions of direct teaching such as Killer Whale methods of cruising the incoming waves to catch prey on shorelines.

Cognitive similarities in social behavior with humans reveal that cetacean complexity is more related to function than body size. Incorporation of structured vocals and visual behaviors in communication indicate higher order cognition. Most notably, echolocation illustrates the remarkability of cetacean cognition; utilization of this cetacean feature is even being pursued in naval counter-terrorism efforts. So, if you get a chance to interact with these fascinating cetaceans, understand they may not be that far down the food chain from humans.

Marino, L. (2007). Cetaceans Have Complex brains for Complex Cognition. PLOS Biology: Online Peer-reviewed journal. Volume 5: Issue 5 (e159)

--contributed by Jerome Lewis



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