Sponges are animals!
OK if you thought sponges were plants.
Scientists didn't even consider them animals until about 100 years
you have sponges in your home? In the kitchen? Bathroom?
Let's think about those sponges at home. They're full of holes
right? Your sponges are probably made of plastic. Natural sponges
are similar in structure and are also full of holes.
To use your sponge at home, you have to squeeze it first right?
The natural sponge, however, can suck water on its own! The water
is filtered through the many holes in the body and tiny bits of
food is gathered from the water flow.
a natural sponge is usually not soft like your home sponge.
The natural sponge usually has lots of spiky bits inside the body
to support itself and to make itself unpleasant for other animals
to eat. So please don't rub yourself with a sponge you find on
the shore! You might get cuts and skin irritation.
Sponges come in all kinds of shapes and colours!
are important to the habitat
many different kinds of sponges can you see?
Describe their shapes, colours, patterns.
can find the biggest sponge? The most colourful?
Sponges have no teeth and can't move. So how do you think
sponges protect themselves? From being eaten? From being
covered by another sponge? Yes, many
sponges have tiny hard spikes throughout their body. Some spikes
are like glass needles. Others contain chemicals that taste bad
or are toxic. A sponge may also release chemicals that irritate
other creatures (including other sponges) and prevent them from
growing over it.
- Sponges as
shelter: many small animals hide on, under and inside sponges.
Why is a sponge a nice place for small animals to stay? What
do YOU like about your home? Can you find food at home? When the
weather is hot do you have an aircon or fan?
A sponge is just like your home. The sponge constantly sucks a
flow of water through itself in order to filter out bits of food.
So it's like having aircon! Some animals may eat the bits of food
that flow in the water too. And most animals find sponges nasty
to eat, so the inside of a sponge is quite safe to hide in.
- Sponges as
food: Despite being spiky and full of nasty-tasting chemicals,
they are eaten by animals such as slugs, fishes and sea turtles.
see if we can find some animals around this sponge? Be
gentle when you look!
Is the animal hiding in the sponge? Or eating it?
bigger animals in fact use sponges for protection! For
example, the velcro crab sticks sponges for camouflage. The nasty
tasting sponges also discourages animals from taking a bite out
- Food chain:
These small animals are in turn eaten by bigger animals.
Recently, sponges are attracting a lot of scientific attention as
sources of interesting new chemicals with medical and other applications.
is NOT true that when you break up a sponge it will reassemble
back together again. A broken sponge may die if the damage
is extensive. Breaking a sponge not only hurts the sponge, but
also the many little animals that live on and inside it.
- A sponge
is NOT a colony! In the way that a hard coral is a colony
of individual animals. A sponge is a simple animal made up of
a few types of cells. These cells are largely independent of one
another and only loosely held together. These cells do not form
tissues or organs, so a sponge does not have a mouth, digestive
system or circulatory system.
Where to find sponges They usually grow on hard surfaces:
rocks, stones, jetty pilings.
Don't step on sponges They are living animals that take
time to grow. Other small animals also live on and inside sponges.
Don't dig or rip! Don't break up a sponge to show the internal
structure or the animals living in them. Use diagrams or photos
included in a guidebook if you have to show them these things.
If you really HAVE to, only use sponges that have washed ashore.
Don't touch: Sponges often have spiky bits and may have
unpleasant chemicals that might cause skin irritation. Worse,
if visitors rub their eyes after handling a sponge!