First Observations of Cooperative Circle Feeding in Southern Right Whales (Eubalaena australis)

Abstract

Marine mammals have developed various feed-ing strategies, including cooperative foraging in groups. Cooperative feeding is more common in social marine mammals like odontocetes that include smaller oceanic dolphins (Neumann & Orams, 2003; Oliveira et al., 2013) and killer whales (Orcinus orca; Similä & Ugarte, 1993; Pitman & Durban, 2012). Cooperative feeding allows these species to hunt more efficiently by working together to gain access to food. For example, common bottlenose dolphins (Tursiops truncatus) can create waves and simultaneously rush towards the shore to catch fish (Gazda et al., 2005; Duffy-Echevarria et al., 2008; Jiménez & Alava, 2015). Dusky dolphin (Lagenorhynchus obscurus) behavior has been studied in Argentina and New Zealand where they exhibit consider-able plasticity in feeding behaviors by using diverse feeding tactics that include herding prey (Würsig & Würsig, 1980), using the shore as a barrier, and feeding individually (Vaughn et al., 2007). Killer whales are found in several dif-ferent ecotypes which feed on varying items, including fish, seals, dolphins, whales, and birds, and have been observed knocking seals into the water from ice floes or herding dolphins coop-eratively (Pitman & Durban, 2012; Coscarella et al., 2015). Contrary to odontocetes, which often feed in large groups, most mysticetes forage singly and independently (Heithaus & Dill, 2008). Nevertheless, cooperative feeding, for example, by using bubble-net feeding (Hain et al., 1982, Wiley et al., 2011; Ware et al., 2014), is relatively well described for humpback whales (Megaptera novaeangliae).