Who invented and who mass manufuactured the first rubber duck? Why are they yellow and were they rubber?
Welcome to the SDMB, Dr Andi .
This site on popular culture has it that rubber ducks came from the rubber squeeze toys manufactured in the late 19th century. The yellow colour is probably in imitation of a cute duckling image.
The precise origin of that other ubiquitous bath toy, the yellow rubber duck, has been lost to the mists of time. We do know, however, that rubber toys enjoyed great popularity after 1839 when Charles Goodyear began making a more elastic and durable form of rubber. The New York Rubber Company was one of the first toy-makers to exploit this new material. By the mid-1800s, their most sought-after product may have been rubber squeak toys that blew air out of a whistle when squeezed, and the rubber duck was likely unveiled around this time.