In this review of the behavioural patterns of chondrichthyan fishes, we have strived to produce a comprehensive catalogue of events and states and develop standardized terminology. Hence, actions that are slightly different, will be pooled under inclusive titles. Those used by different investigators are included in quotations within the textual descriptions of the motor patterns. This standardized ethogram will ideally lead to an increase in inter-observer reliability, giving researchers more confidence when reading colleagues’ papers 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) defence. 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’.

The expanding shark fin market has resulted in intensive global shark fishing and with 90% of teleost fish stocks over-exploited, sharks have become the most lucrative target. As predators, they have high ecological value, are sensitive to fishing pressure, and are in decline, but the secretive nature of the fin trade and difficulties obtaining relevant data, obscure their true status. In consumer countries, shark fin is a luxury item and rich consumers pay high prices with little interest in sustainability or legal trade. Thus, market demand will continue to fuel the shark hunt and those accessible to fishing fleets are increasingly endangered. Current legal protections are not working, as exemplified by the case of the shortfin mako shark, and claims that sharks can be sustainably fished under these circumstances are shown to be misguided. In the interests of averting a catastrophic collapse across the planet’s aquatic ecosystems, sharks and their habitats must be given effective protection. We recommend that all sharks, chimaeras, manta rays, devil rays, and rhino rays be protected from international trade through an immediate CITES Appendix I listing. However, a binding international agreement for the protection of biodiversity in general is what is needed.

The chondrichthyan lineage diverged from the osteichthyan line around 440 million years ago, resulting in a vast evolutionary gulf between modern elasmobranchs and other vertebrates. Though this has supported the assumption that as an ancient line, elasmobranchs are dangerously stupid, intelligent actions including social interactions have been noted in the field, while laboratory studies have confirmed a variety of cognitive capacities. Yet, due to fear of sharks and the difficulties of observing them in their aquatic environments, few ethological studies have been done, so their natural behaviour remains little known. On noting that the blacktip reef shark, Carcharhinus melanopterus, displayed complex actions during incidental meetings, a long-term ethological study of the species was carried out on the north shore of Mo’orea Island, French Polynesia. During the 6.5 years of the study, new behaviours continued to present. The 35 context-specific actions identified as comprising the behavioural repertoire of C. melanopterus are described.

While studying the behaviour of a community of blackfin reef sharks, there was a four month long episode during which the entire company of residents and their visitors showed evidence of feeling a negative emotion towards me. They directed a variety of menacing gestures towards me, and their behaviour escalated until they began battering my kayak on my arrival in their range. Underwater, three would have slammed me personally had I not fought them off. Their behaviour suggested that their cognitive functions are complex, for they held their negative attitude in mind long-term. Two years later, under different conditions, they conveyed, via body language, a positive emotion. Social learning, social buffering, and emotional contagion were also displayed in their actions.