When mammals returned to the sea: the ecological implications of re-adaption to marine life in a rapidly changing world

Our understanding of ecological patterns across mammals has been limited as research has focused on terrestrial mammals alone. Ecological patterns have been examined in marine and terrestrial mammals in isolation and without... [ view full abstract ]

Our understanding of ecological patterns across mammals has been limited as research has focused on terrestrial mammals alone. Ecological patterns have been examined in marine and terrestrial mammals in isolation and without considering phylogenetic information.
Marine mammals appeared over the last 65 million years. This was an experiment run several times (at least 7 that we know of) and across different mammalian groups. While many of these lines disappeared, today there are five extant groups, the cetaceans (whales, dolphins and porpoises), sirenians (dugong and manatees), pinnipeds (seals, sea lions, and walrus), sea otters and polar bear. Alongside the obvious anatomical and physiological changes in marine mammals, moving back into the marine environment was accompanied by changes to ecological patterns. Through comparative studies we have found that marine mammals have larger home ranges for their body size, they use different foraging strategies and different communication patterns compared to terrestrial mammals.
Through empirical studies we examine how different mammal models, and from different systems (Antarctic pack ice, Southern Oceans, Tasmanian forests), are responding to recent environmental change. Our studies of foraging behaviour of Antarctic pack ice seals have found that within the Western Antarctic Peninsula (WAP), where local warming is causing some of the greatest environmental shifts on the planet, the top predators show a dramatic trophic downshift. We follow behaviour change in the world’s largest animal, the blue whales, over the past two decades.
Combining comparative approaches, to understand large-scale patterns across ecological and evolutionary time, along with contemporary studies aids our understanding of species vulnerability to changing environments.