Quick Definition
Comb-like projections on the gill arches used to filter plankton or prevent food items from escaping through the gill slits.
📖 Full Definition
Gill rakers are bony or cartilaginous projections that arise from the inner face of gill arches, forming a sieve-like array. Their length, spacing, and number are closely correlated with diet: piscivores have widely-spaced, short rakers that allow small organisms to pass while retaining large prey; planktivores have long, closely-spaced rakers that act as a fine sieve for zooplankton and phytoplankton. Filter-feeding giants (whale shark, basking shark, manta ray, bluefin herring) have the most elaborate gill raker structures, approaching the complexity of whale baleen. Gill raker counts (on the first gill arch) are important species identification characters.
💡 Examples & Context
The whale shark has thousands of densely-packed cartilaginous gill rakers forming pads that filter plankton from enormous volumes of water passing through its cavernous 1.5-metre-wide mouth.