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.
Komposisi paruhnya — terdiri dari kitin, air, dan protein — memadat secara bertahap dari pangkal ke ujungnya sehingga cumi - cumi dapat menggunakan paruhnya tanpa akibat bahaya abrasi.