In polluted environments, dolphins gradually accumulated toxins in their body fat, and the larger the dolphin the more accumulated toxin it can tolerate  Nearly 80 percent of the toxins a female dolphin has accumulated pass into the fat-rich milk her nursing calf ingests
Ttherefore, the unusually high mortality rate among dolphin calves in the industrially contaminated waters along Florida' s Gulf Coast is probably the result of their being poisoned by their mother' s milk
Dolphins, like other marine mammals, have a higher proportion of body fat than do most land mammals.