The pesticide DDT, banned decades ago in much of the world, still shows up in penguins in Antarctica, probably due to the chemical's accumulation in melting glaciers, a sea bird expert said on Friday. Adelie penguins, known for their waddling gait and a habit of nesting on stones, have long shown evidence of DDT in their fatty tissues, although not in enough concentration to hurt the birds, according to Heidi Geisz of the Virginia Institute of Marine Science.