Prehistoric #baby bottles: marvellous feeding vessels in the shape of #animals from Vösendorf and Oberleis, Austria, dating 1200-800 BC.
Baby bottles in the shape of animals are common in late Bronze and early Iron Age Europe.
This article describes bottles found in children's graves, so maybe similar? I can't tell if they're the same bottles, but that would be one way for evidence to point to child bottles specifically. Good question though.