Cetacea--Behavior

Anthropogenic contaminants in the marine environment often biodegrade slowly, bioaccumulate in organisms, and can cause reproductive, immune, and developmental effects on wildlife; however, their effects on cetacean health and behavior have not been extensively studied. This study aims to expand knowledge concerning concentrations and biological effects of endocrine disrupting contaminants and essential and non-essential inorganic elements in stranded cetaceans. We evaluated tissue samples and pathology data from 66 odontocetes that stranded in the southeastern United States during 2012– 2017. Using mass spectrometry blubber samples were analyzed for five endocrine disrupting contaminants (atrazine, bisphenol-A, diethyl phthalate, nonylphenol ethoxylate, triclosan), and liver samples were analyzed for 12 inorganic elements (As, Cd, Co, Cu, Mg, Mn, Fe, Pb, Hg, Se, Tl, Zn). Results from this study demonstrate that exposure to certain contaminants may be associated with subtle or sublethal cellular changes in free-ranging marine mammals that could contribute to health declines or stranding.

The present study examined the alteration of benthic foraging behavior by mother Atlantic spotted dolphins (Stenella frontalis) when foraging in the presence of their calves in comparison to the foraging behaviors of the mothers when the calves were not present. The mother dolphins chased prey significantly longer and made significantly more body-orienting movements during foraging in which calves were present. In 5 of the events where the calves were present the prey was not eaten by the mother, but instead the calves were allowed to pursue the prey and were confirmed to have eaten the prey in 3 of the foraging events, even though the calves were still nursing. Additionally, this altered foraging behavior only occurred in the presence of their naive calves. Therefore, the present study may be evidence of teaching as a potential social learning mechanism of foraging behavior by Atlantic spotted dolphins.