Explain: LOBSTER,CRABS, FISH What Do Ocean Animals Need to Survive
Explain: LOBSTER,CRABS, FISH – what do ocean animals need to survive?
Lobsters
What do Lobsters need to survive?
Lobster – lobsters are crustaceans meaning that they have a hard outer shell or exoskeleton that forms their body. They are related to the cockroach family. They live in every ocean in the world. They molt or shed their shells 2 times per year because as they grow they get too big for their shell. Soon after molting they are vulnerable to predators because their shell is very soft and therefore have to hide by burrowing into the sea bottom or cave until their shell can harden.
Food
Lobsters eat fish, crabs, clams, mussels, sea urchins, star fish and if their normal food source in not available they will eat plant life or sea weed. They are omnivores which mean they eat both meat and plants.
FOOD -Lobster going after food - http://www.naturefootage.com/video_clips/ST01_044a
Lobsters usually hunt at night using their antennae on their heads and tiny hairs all over their body to help guide them along the ocean floor looking for prey. They have a very good sense of smell that guides them towards their prey.
Lobster foraging for food/camouflage/antenna for smell/defense http://www.naturefootage.com/video_clips/FG31_076
A lobster’s teeth are in their stomach which is right next to their mouths. So when they bite into their prey it goes right to their stomachs where the lobster uses three grinding surfaces like molars to chew. These molars look like human molars.
Space
Scientists have used GPS tracking devices on lobsters to help them study how much territory or space they need to survive. Through tracking lobsters this way it was found that they need approximately a six mile stretch of ocean floor to survive. This gives them enough room to hunt and survive successfully.
Lobsters moving together across ocean floor for protection - http://video.kids.nationalgeographic.com/video/player/kids/animals-pets-kids/invertebrates-kids/lobster-locomotion-kids.html
Shelter
Lobsters like places that have a lot of cover for protection from predators. They live in places such as coral reefs, rock pilings, bridge pilings, piers, abandoned lava tubes (on the ocean floor), as well as, the roots of mangrove trees. They can live anywhere from shallow water all the way to the ocean floor. Lobsters also burrow into the mud of the ocean floor. Like many other animals lobsters can fight over a good shelter spot. The lobsters color also helps to camouflage itself from predators causing it to blend into its surroundings making it hard for its enemies to see it.
SHELTER/SPACE - Lobster burrowing for shelter while keeping sensors out in water - http://www.naturefootage.com/video_clips/CMO02_127
SHELTER - Lobster hiding from diver in cave/shelter http://www.naturefootage.com/video_clips/HIT01_054
SPACE - Lobsters fighting over territory http://www.naturefootage.com/video_clips/ST01_041
Water/Air
Lobsters need air and water together as another mechanism for survival. Lobsters have gills that they use to breathe through. They are located beneath or bottom of their shell. They get air or oxygen from the moisture or water that clings to their gills causing them to breath.
AIR - Lobster oxygenating eggs - http://www.naturefootage.com/video_clips/GMO01_004 - This video shows a lobster using its gills to push water and oxygen over its eggs underneath its tail. It breaths the same way.
You may ask how does a lobster breathe underwater? Well, there are tiny little bubbles of air that they pull out of the water and filter through their gills. Have you ever shaken a bottle of water or blown bubbles in a glass of water? When you do you can see tiny bubble of air. This is similar to what the lobster uses to breath.
How long can a lobster live outside of water? Usually about 48 hours as long as it stays in a cool and moist place. Lobsters have learned to adapt in this way because sometimes they get stuck out of the water during low tide. Stranded lobsters will look for shelter under rocks that are covered in wet sea weed since they must remain cold and wet to survive out of water for longer periods of time.
Children’s Book Reference: Lobster’s Secret by Kathleen M. Hollenbeck
Pictures as visual resources:
Hermit crabs
What do hermit crabs need to survive?
Food
Hermit crabs in the wild eat fallen fruit, decaying wood, leaf litter, plants and grasses, and items washed ashore by the tide. They are not fussy eaters. As pets they eat mostly what we eat without the chemicals and sugar. They like meats such as fish, vegetables such as broccoli, carrots, lettuce, spinach, and fruits such as apples, bananas and grapes. They locate their food by smelling it and by seeing other crabs eating.
Video http://www.naturefootage.com/video_clips/CL03_022 - hermit crabs eating fish
Water
Hermit crabs need plenty of fresh water to drink but they also get water from the foods they eat and the dew on plants. Hermit crabs kept as pets should be sprayed with water daily so they have plenty of humidity in their environment and/or need a wet sponge in their tank.
Air
Hermit crabs have modified gills that allow them to breathe air but the gills and air must be humid (moist) or they will suffocate. They pull oxygen out of the water and out of the air to survive
Shelter
The most interesting fact about hermit crabs is that they use discarded sea shells (usually from snails) as their “home” and they carry their home on their backs as they move around. The shell provides protection because the back part of the crab’s body is soft. As the hermit crab grows he has to find a bigger shell so he looks around, tries on several shells for size, until he finds the shell that is just right.
Sometimes the hermit crab decorates its shell by carrying other things from the sea on its shell. These “decorations” provide protection through camouflage.
Read aloud book, A House for Hermit Crab by Eric Carle
Video http://www.youtube.com/watch?v=0jZe_VGLRYI – hermit crab changing from one shell to another
Video http://www.youtube.com/watch?v=TaaZD6gX4Rw&safety_mode=true&persist_safety_mode=1 – giant sea snail eats smaller snail and hermit crabs fight for shell
Sea Star
What do Sea Stars need to survive?
Sea stars (also known as starfish) are spiny, hard-skinned animals that live on the rocky sea floor. These invertebrates are NOT fish; they are echinoderms.(see below) Sea stars move very slowly along the sea bed, using hundreds of tiny tube feet. There are over 2,000 different species of sea stars worldwide.
Most sea stars have five arms (or a multiple of five) that radiate from a central disk. There arms are also referred as rays. If a sea star looses one of its rays, a new one will regenerate. Sometimes a ray can grow a whole new sea star. Sea stars do not have a brain; they have a simple ring of nerve cells that moves information around the body. Eyespots (primitive light sensors) are at the tip of each arm.
Food
Sea stars are carnivores (meat-eaters). They eat clams, oysters, snails, coral, fish, and other animals. They push their stomach out through their mouth (located on the underside of the sea star) and digest the prey. Starfish with suction disks use them to hold and force open the shells of shellfish. Once it has opened a shell, the starfish extends its stomach membranes from its mouth, inserts them into the shell opening, and secretes digestive juices that break down the shellfish's body into a form that can be absorbed into the stomach membranes. Starfish without suction disks swallow their prey whole, and eject the parts that are not digestible. Starfish are not eaten by humans.
Sea stars can “smell” food in the water. But, of course, they don’t use noses to do this smelling. Sea stars don’t even have noses. Instead, they use their skin. Sea stars have sensitive cells on their skin. Some of these cells can detect chemicals in the water that come from food. Some sea stars can also “smell” food with their tube feet.
Once a sea star detects food, it can move toward its prey. But a sea star isn’t going to win many races. Normally, a sea star crawls very slowly—less than 1 foot (30 centimeters) in a minute. When it is “chasing” prey, it can speed up. Then it may be able to crawl 2 1/2 feet (76 centimeters) in a minute.
Video http://www.youtube.com/watch?v=A100m5EpfFI –sea star eating a piece of scallop with great video of the tube feet
Water
Sea stars do not have eyes as people do. But, they do have eyespots. These spots are groups of cells that can detect light. Sea stars have these eyespots at the tips of their arms.
Eyespots help a sea star when it’s out of water. A sea star may end up on the beach at low tide. If it stays in the sun too long, its body may dry out. That would cause the sea star to die. With its eyespots, the sea star can find its way to shade. In the shade, the sea star can stay cool and damp until the water level rises again at high tide. The sea star needs the water to survive.
Shelter
Sea stars live in all of the world’s oceans. They are found in cold waters, in the deep ocean and on coral reefs or kelp forests. The colors and patterns assist the sea star in camouflaging itself from predators. The bright hues also care the predators away.
A sea star uses its tube feet for walking, clinging, and grabbing food. Some sea stars have tube feet that can grip like suction cups. Here’s how that works. First, seawater enters the sea star through a hole on top of its body. The water then flows through the tube system and into the tube feet. The water causes the tube foot to lengthen and spread out. When the foot is pressed against a hard surface, it shrinks. This helps the tube foot stick. Then the sea star releases a substance like glue from its foot.
When the sea star is ready to let go, it stretches its foot out again. It releases another substance. This new substance stops the glue from sticking.
Camouflage videos https://www.naturefootage.com/video_clips/TM04_017
http://www.naturefootage.com/video_clips/DZ91_115
http://www.naturefootage.com/video_clips/DI04_060
video https://www.youtube.com/watch?v=4IRF-pKVtuU&saftety_mode=true&persist_safety_mode=1 – shows tube feet
Read alouds: A Sea Star by Anne Miranda and Sea Star by: Lola M. Schaefer