The composition of the beak ​ — which is made up of chitin, water, and protein — ​ changes in density so gradually from soft to hard that the squid can use its beak without causing any harmful abrasion.
Pāreja no mazāka blīvuma uz lielāku knābī ir tik pakāpeniska, ka kalmārs var lietot savu knābi, pats sev nekaitējot.