How do invertebrates move around?
Polar seastar on the move
This seastar has four rows of small tube feet under each arm.
A seastar gets around by moving its suction feet.
A waved whelk on the move
A waved whelk is a marine snail. The brown disk on its back is called an operculum. The whelk uses it to close off its shell and protect itself.
The muscles in its foot contract in waves, allowing it to glide along the film of transparent mucus that it secretes.
It uses its tentacles and eyes to explore its environment, and its siphon to breathe and detect odours.
A sand dollar on the move
It uses the five rows of tube feet arranged in a star under its body to move about and burrow into the bottom to hide.
Sand dollars are hard to spot. They spend most of their time buried in the sand on the bottom, where they find food and shelter.
A sea cucumber on the move
That’s no vegetable!
A sea cucumber is not a vegetable, but a slow-moving marine animal.
It uses its tube feet to move around and anchor itself. Note how it contracts its body to help it move.
This sea cucumber is climbing up the wall of an aquarium, so you can see its four rows of tubular suction feet.
A northern sea anemone on the move
Animal or flower?
A northern sea anemone is an animal that looks like a large flower.
It has a series of vertical muscles that allow it to bend in every direction.
To move, it stretches one side of its pedal disk and then contracts it. This shifts its centre of gravity in that direction.
It can also drift with the current and attach itself wherever the current takes it..
A blood seastar on the move
Do you see how this tiny seastar moves about to explore its environment?.
For more information
For more information and to see how it is able to move so far, take a look at its larger cousin, the polar seastar, on the move.
A green sea urchin on the move
The spines on a sea urchin’s body, some of them short and some long, are able to move.
Cinq doubles rangées de pieds « ambulacraires » lui permettent de se déplacer.
It contracts and expands its five double rows of tube feet to move around.
A spider crab on the move
How many legs?
Like most crabs, a spider crab doesn’t swim, but uses its eight legs to move quickly across the bottom.
Its pincers are modified legs that also help it get around.
It tends to move sideways because of the shape and hardness of its shell and the arrangement of its legs.