How Do Octopuses Change Shape?

What You'll Learn

• Octopuses have no bones — their entire body is soft except their beak
• The beak is the only hard part — like a parrot's beak
• If a hole is big enough for the beak, the octopus can squeeze through it
• Octopuses can change color and texture to camouflage
• They have special skin cells called chromatophores that change color

Words to Know

Octopus

A sea animal with eight arms and no bones

"The octopus squeezed through a tiny hole."

Beak

The hard mouth of an octopus

"The beak is the only hard part."

Chromatophore

A tiny color-changing sac in the skin

"Chromatophores let octopuses change color."

Camouflage

Blending in with surroundings

"The octopus used camouflage to hide."

Check What You Learned

Fun Facts

• Octopuses have no skeletal system — entirely soft-bodied

  Source: Marine Biological Association

• The only hard structure is the beak (mandible), made of chitin

  Source: Journal of Morphology

• "Beak rule" — if a hole fits the beak, the whole octopus can squeeze through

  Source: Marine Biology

• A 60-pound octopus squeezed through a 2-inch hole

  Source: Monterey Bay Aquarium

• Chromatophores — pigment sacs that expand/contract to change color

  Source: J. Experimental Biology

• Color change in less than a second — controlled by nervous system

  Source: Current Biology