How fast can a Starfish move? How do Starfish move?
How fast can a Starfish move?
Starfish don’t move very fast. In fact, they are slow moving as compared to the majority of the snails.
They move with an average of about 1 meters per minute and with a maximum speed of about 1.6 meters per minute in a majority of the species.
Starfish movement rates vary from 0.3 mm/s (millimeters per second) in the “sun star” Crossaster papposus to a breathtaking 50 mm/s.
Starfish may move in a bilateral fashion, meaning that they can use the right and left sides of their body together at the same time or with alternating movements, to move. Most probably that’s seen particularly when hunting or in danger.
When crawling, certain arms act as the leading arms, while others trail behind.
Some of the starfish species like the Leather star (Dermasterias imbricata) can manage to move with just a speed of about 15 cm per minute. That’s too slow from the average starfish speed mentioned above.
Some burrowing species from the genera Astropecten and Luidia have points rather than suckers on their long tube feet and are capable of much more rapid movement.
Just take the example of the Sand starfish (Luidia foliolata) that can travel at a speed of 2.8 m per minute. That’s very fast from the speed of the majority of the starfish species.
They use the ocean water current to help them move. That movement is due to the hydraulic pressure mechanism exerted from their water vascular system.
You will often see them moving very fast during the times of high sea waves. That movement is not due to their own biological system, but due to the force exerted by the waves throwing them to the seashore.
Starfish that are discovered to date are all known to be very slow marine creatures. Some are somewhat fast but not so super fast to shock you.
In fact, if we compare the top slowest animals on earth, then you will find the Sloth bear to be the slowest animal in the world, and the second position comes for the Starfish.
Are Starfish really fast?
No, starfish are not fast-moving when compared to the other animals that live both in land and in water.
In fact, starfish can be considered as the second slowest animal on planet earth discovered so far.
They move due to the water current prevailing inside of their body’s water vascular system. Seawater is pumped into the animal’s water vascular system through its madreporite that moves the tube feet.
The water gets inside and creates hydraulic pressure leading to its movement.
Now, what’s the catch?
The pressure so created due to the movement of the water current inside their body results in a very slow movement. You can just say that the water helps to displace the creature allowing it to remain stable, but mobile.
They are so slow that the Starfish movement rates vary from 0.3 mm/sec in the Sun star (Crossaster papposus) to a breathtaking 50 mm/sec in many known species.
It has been seen that the speed of the starfish is directly dependent on the size of the starfish. That is, the larger the starfish size, the fast it can move.
It is said so because the young starfish belonging to the same species move very slowly as compared to the adult large-sized one of the same species.
Thus, it can be said that the movement speed is directly dependent on the size of the starfish and it’s thought that larger size does have some relationship to speed and some of the fastest species listed are also among the largest.
However, this concept isn’t universally true with all of the species known so far but, with the majority of the species.
For your information, Sand Starfish (Luidia ciliaris) that can be majorly seen in the oceans near North Atlantic around Europe and the UK, is considered to be among the fastest Starfish discovered so far.
How do Starfish move? How they use the tube feet and water vascular system for movement?
Starfish move by the combined action of their tube feet. These tube feet are located in the ventral (oral side) of the starfish below each of its arms.
Every arm bears at least two rows of tube feet on the oral side. These tube feet help in attachment to the substratum.
It is estimated that the starfish has somewhere between one thousand tube feet on one arm.
Each of the tube feet consists of two parts: the ampulla and the podium. The ampulla is a water-filled sac containing both circular muscles and longitudinal muscle. The podium is the tube-shaped structure containing longitudinal muscle only.
The podium has a flattened tip that can act as a sucker to hold on to the substratum firmly and precisely.
Starfish also have madreporite. Madreporite or sieve plate is like a small, smooth plate, at the entrance of the sea fishes water vascular system, through which the seawater enters the water vascular system of the starfish.
The madreporite is located on the aboral side of the starfish, slightly off the center.
The seawater enters through the madreporite and fills all the canal inside the starfish including the tube feet. That canal system attached to the tube feet is also called the water vascular system.
As the water enters the canal system it makes its way towards the ampulla of the tube feet. As a result, due to the pressure of the water the ampulla contracts, squeezing water down into the tube foot. This results in a hydraulic pressure to hold the substratum using the sucker of the tube feet.
To retract the tube feet, the ampulla relaxes. So, the extension and retraction of the tube feet results in the movement of the starfish.
The ampulla of the tube feet are able to contract and relax due to the action of the circular muscles. And the podium attaches and detaches itself from the substratum due to the action of longitudinal muscles present there.
The hydraulic pressure thus formed causes the vacuum action of the sucker attached at the base of the podium.
During the locomotory movement, one or two arms of the starfish serve as leading arms, and all the tube feet extend in the same direction in a coordinated manner.
As a result, the starfish moves forward steadily but slowly. They are also able to climb up the rocks inside the ocean by the combined action of their tube feet.
Do Starfish move a lot?
No, starfish do not move a lot. They are only seen to be moving a lot during the time they feed or when they need to escape from their potential predators.
They normally seem to be lying down in the ocean bed, but during the time of movement their tube feet stretch and contract to attach to rough terrain, hold on to prey and, of course move.
These sea animals usually prefer rocky areas allowing them to cling to the rocks in the ocean bed. So, you’ll often find them in rocky areas just below sea level like tide pools.
Usually, you will see them only moving from one rock to another very slowly, but not in a continuous state of motion.
And, it’s very rare to see them hunting for their prey, and getting rid of predators.
They do the most unique type of advanced movement when they feed on the mollusks (like snails, slugs, clams, oysters, etc). They locate their prey with light-sensing eyespots at their arm tips, then pry open the mollusks’ shells with hundreds of suction-cupped tube feet.
During their feeding time, you’ll definitely find them moving. So, after finding their food they slowly move near to their prey using their suction type tube feet.
The suction of the tube feet forces open the shell of the mollusks with suction disks on the underside of its body and then inserts its stomach membranes through its mouth.
Can Starfish move on land?
Yes, they can move on land but not for a very long time. Their body is meant for moving inside the water in the most perfect way possible.
Watching a starfish walking on land is very rare as you’ll hardly find them in the seashore.
But, during the time of stormy weather, you will find large masses of starfish being washed ashore and lying on the seashore. It’s because the ocean tides can sometimes throw them out of the water on the beach.
So, they will eventually find their way back to the sea if they get washed ashore. They will use their tube feet to slowly make their way back to the sea.
While the starfish may appear to be stranded, they also have the ability to return to the water when they’ve been exposed for too long.
So, touching them is not recommended as they will eventually make their way to the ocean.
Some can even die when they get washed ashore. It’s because when it is exposed to the open air it can no more breathe and so die within minutes.
However, in very rare cases you’ll find them washed very far away from the water on the shore. During that time they will try hard to move slowly back to the water using their tube feet, but if they have to cover a long distance that can take more then 3 to 5 minutes they can die for not being able to breathe in the open air.