Macphail’s comparative approach to intelligence focused on associative processes, an orientation inconsistent with more multifaceted lay and scientific understandings of the term. His ultimate emphasis on associative processes indicated few differences in intelligence among vertebrates. We explore options more attuned to common definitions by considering intelligence in terms of richness of representations of the world, the interconnectivity of those representations, the ability to flexibly change those connections, knowledge, and individual differences. We focus on marine mammals, represented by the amphibious (...) class='Hi'>pinnipeds and the aquatic cetaceans and sirenians, as animals that transitioned from a terrestrial existence to an aquatic one, experiencing major changes in ecological pressures. They adapted with morphological transformations related to streamlining the body, physiological changes in respiration and thermoregulation, and sensory/perceptual changes, including echolocation capabilities and diminished olfaction in many cetaceans, both in-air and underwater visual focus, and enhanced senses of touch in pinnipeds and sirenians. Having a terrestrial foundation on which aquatic capacities were overlaid likely affected their cognitive abilities. Vocal and behavioral observational learning capabilities in the wild and in laboratory experiments suggest versatility in group coordination. Empirical reports on aspects of intelligent behavior like problem-solving, spatial learning, and concept learning by various species of cetaceans and pinnipeds, suggest rich cognitive abilities. The high energy demands of the brain suggest brain-intelligence relationships might be fruitful areas for the study when specific hypotheses are considered, e.g., brain mapping indicates hypertrophy of specific sensory areas in marine mammals. Modern neuroimaging techniques provide ways to study neural connectivity, and the patterns of connections between sensory, motor, and other cortical regions provide a biological framework for exploring how animals represent and flexibly use information in navigating and learning about their environment. At this stage of marine mammal research, it would still be prudent to follow Macphail’s caution that it is premature to make strong comparative statements without more empirical evidence, but an approach that includes learning more about how animals flexibly link information across multiple representations could be a productive way of comparing species by allowing them to use their specific strengths within comparative tasks. (shrink)

Conducting marine mammal research can raise several important ethical issues. For example, the continuation of whaling for commercial purposes despite the international moratorium provides opportunities for scientists to obtain data and tissue samples. In 2021 we analysed 35 peer-reviewed papers reporting research based on collaborations with Icelandic whalers. Results highlighted little consideration or understanding of the legal and ethical issues associated with the deliberate killing of whales amongst those researchers, funding bodies, universities and journals involved. Ethical statements were rarely provided. (...) Those that were written were incomplete. Whilst research using whaling data may seem acceptable to some, it often becomes hard to justify when subject to scrutiny by the media and the public. Thus, there is a particular danger of reputational harm for early career researchers who may become unwittingly involved in such activities. Here we also consider the broader variety of ethical issues raised by non-lethal research (both historical and recent) on marine mammals including tagging and biopsy. We discuss instances where study animals were harmed or even killed and where the public mistook tags for harpoons. Without clear guidelines, reviewers and journal editors are put in an impossible position when considering whether to reject papers on ethical grounds. We propose that for such studies, universities, funders, journals, and permit issuers must require ethical assessments and that journals more effectively implement their existing policies on publishing ethical statements. The professional marine mammal societies need to work together to produce modern ethical guidance. Such guidance should require transparency in the provenance of data and samples while including advice on law, welfare issues, involvement of local scientists, and offshoring. Furthermore, it should require appraisal of and justification for the absolute necessity of invasive procedures. As is already the case in biomedical disciplines, ethical statements should be required in marine mammal science. (shrink)