Strangely a sponge is classified as an animal, even though it has no eyes, ears, mouth, heart, stomach or even a basic nervous system.
The main reason for this classification is due to the way that they feed. Sponges do not make or produce their own food in the way that plants do, they actually capture their food.
The entire surface of a sponge is covered in tiny pores. The smallest of marine life and plants flow into the pores and then enter a system of water canals throughout the main body of the sponge. Once they have been captured in this way, the food is digested and the canal system washes away the waste. Since sponges do not actively capture their prey, they are in effect acting like a filter or sieve.
Most of the sponges which are sold as such are simply synthetic materials which have been made to resemble natural sponges, which given that they eat and produce body waste, may be a good thing !
The main reason for this classification is due to the way that they feed. Sponges do not make or produce their own food in the way that plants do, they actually capture their food.
The entire surface of a sponge is covered in tiny pores. The smallest of marine life and plants flow into the pores and then enter a system of water canals throughout the main body of the sponge. Once they have been captured in this way, the food is digested and the canal system washes away the waste. Since sponges do not actively capture their prey, they are in effect acting like a filter or sieve.
Most of the sponges which are sold as such are simply synthetic materials which have been made to resemble natural sponges, which given that they eat and produce body waste, may be a good thing !