Cephalopods: Arms or Tentacles?

We’re celebrating Cephalopod Awareness Week by looking at the difference between arms and tentacles. 

Published October 03, 2017

Cephalopods are a class of marine mollusks including the octopus, cuttlefish and squid. The name cephalopod means "head-foot" because they have limbs attached to their head, and these mollusks are well-known for their arms and tentacles. And while all cephalopods have arms, not all cephalopods have tentacles. 

octopus-arms

Tentacles are long, flexible organs found on invertebrate animals. They are important for feeding, sensing and grasping. Tentacles are longer than arms, are retractable and have a flattened tip that is covered in suckers. 

Arms are similar to tentacles, but still distinctly different. Arms are covered with suckers that help with grasping food items. In addition, these arms are useful to attach to surfaces while resting. 
The names may seem interchangeable, but when it comes to cephalopods, there’s a difference between arms and tentacles. An easy way to spot the difference is that arms have suckers along their entire length, while tentacles only have suckers at the tip. 

This means that octopuses have eight arms and no tentacles, while other cephalopods—such as cuttlefish and squids—have eight arms and two tentacles.

Learn more about our eight-armed cephalopod, the giant Pacific octopus, here!

 
Previous Post

Featured Stories

sea-turtle-swim-test Animal Rescue Update: The First Patients of Cold-Stunning Season

It was a busy holiday weekend for our Animal Rescue and Animal Health teams as they triaged 30 sea turtles that stranded on the coast of New England. 

Read the full story

leopard-shark-kelp-forest You Asked, We Answered: Do Sharks Make Noise?

Dolphins make clicking noises and whales emit deep, low hums to echolocate and communicate, but what about sharks?

Read the full story

Related Stories

End of Year Roundup: Baby Animals

Published December 12, 2017

Species Spotlight: Green Honeycreeper

Published December 08, 2017