A review of the behaviours of the Chondrichthyes: a multi-species ethogram for the chimaeras, sharks, and rays

What is it about?

In this review of the behavioural patterns of chondrichthyan fishes, we have strived to produce a comprehensive catalogue of events and states, striving to develop a standardized terminology. This ethogram will ideally lead to an increase in inter-observer reliability, giving researchers more confidence when reading papers of their colleagues that report behaviours that appear similar to theirs despite being described for different species. The descriptions are presented under the following categories: 1) maintenance, 2) courtship, 3) filter feeding, 4) scavenging, 5) predation, 6) sociality, 7) aggression, and 8) defense. The many actions are illustrated by line drawings and photographs in composite figures with an attempt to provide an example of each action for a chimaera, shark, and ray. The diversity of patterns is evident from this ethogram, consistent with observation that the brain-to-body mass ratios of cartilaginous fishes are greater than a third of the bird species and greater than those for some mammalian species. The major impetus for assembling this ethogram is to demonstrate the diversity of behaviours exhibited by members of the Chondrichthyes and to dispel the apocryphal belief that members of this taxon are “simple feeding machines”.

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