Cephalopod beak

, surrounded by the buccal mass and limbs Composed primarily of chitin and cross-linked proteins, beaks are more or less indigestible and are often the only identifiable cephalopod remains found in the stomachs of predatory species such as sperm whales. Cephalopod beaks gradually become less stiff as one moves from the tip to the base, a gradient that results from differing chemical composition. In hydrated beaks of the Humboldt squid (Dosidicus gigas) this stiffness gradient spans two orders of magnitude. ==Measurements==

The abbreviations LRL and URL are commonly used in teuthology to refer to lower rostral length and upper rostral length, respectively. These are the standard measures of beak-size in Decapodiformes; hood length is preferred for Octopodiformes. ==References==