Figure 1.

Hierarchical morphology of humpback whale baleen, from the level of the whole baleen apparatus down to the level of protein domains within 10 nm intermediate filaments. In the current study, mechanical tests were performed on bristles that were detached from the lingual edge of baleen plates. Baleen plates consist of horn tubules embedded in intertubular horn. Bristles are simply tubules that have become exposed at the lingual edge owing to the wearing away of intertubular horn. This diagram applies to the structure of baleen in all rorqual whales, but significant variation exists among species with regard to the amount and location of calcium salt crystallites.