Invertebrates

1. Invertebrates 9. Octopus and Starfish

2. An octopus is a mollusk that has no shell at all It looks as if it is all head and arms

3. An octopus has eight (8) arms, called tentacles, which have many suckers on them

4. Suckers hold on tightly to objects they touch The suckers help an octopus to crawl and to hold on to its food

5. An octopus moves by pulling itself along by its tentacles It can also use a kind of jet propulsion to move

6. It pulls in water through its gills and sends it out very fast through a tube under its head The force of the water moves the octopus backward

7. One way that an octopus can find food is by hiding among stones and seashells on the ocean floor The octopus can change its color to match its surroundings

8. Small water animals that swim by usually do not see the octopus The octopus can grab an animal with its tentacles

9. Most kinds of octopuses are as small as a person’s fist How do they escape bigger animals that feed on them?

10. An octopus can squirt out a liquid, like ink, that blackens the water The octopus then swims away

11. Giant octopuses that live in the Pacific Ocean have few enemies to swim away from These octopuses can grow to be 30 feet long

12. Starfish live in all oceans Fish is part of their name, but they are not fish but invertebrates

13. Starfish have a small central body, with a mouth on the bottom side Most starfish have five arms that stick out from their bodies

14. Other kinds have more than 25 arms Stiff spines cover their bodies and arms

15. Starfish are often dull yellow or orange but can be bright colors, too They can be as small as ½ inch and as big as 3 feet wide

16. Starfish use their tube feet to move These small tube feet are under each arm

17. Suction cups are attached to the feet Suction cups help starfish to move

18. Starfish eat animals, especially like clams and other mollusks A starfish catches a clam with its arms

19. The clam closes its shell to protect itself Using its tube feet, the starfish forces the shell open a little bit

20. Then the starfish turns its stomach inside out and pushes it out of its mouth It sticks its stomach into the opened clamshell and eats the soft clam body

21. Then the starfish pulls its stomach out of the clam and puts it back into its own body

22. A starfish can grow new arms if its arms are broken off This is called regeneration

23. In fact, if a starfish loses all its arms but one and most of its central body a new body and new arms will grow

24. Starfish eat mollusks like clams and oysters that are valuable crops for fishermen The fishermen may try to destroy starfish by cutting them into pieces

25. But the pieces grow into even more starfish!