Slowest animal in North America are the sessile animals

The Sessile Animals – Corals and Sea Sponges and Mussels

The slowest animals make their homes in some of the fastest places on earth: reefs and oceans. Some of these creatures can only float in place while others use their super-slow bodies to anchor themselves in place as they filter food from the water around them.

Sessile animals are not just only slow, but also immobile. They cannot move from one place to another like other animals. They do not have limbs, muscles, nerves and other organs that help in movement. So, how do they survive? Well, it is the environmental conditions that favor their survival.

They remain attached to a surface for their whole life cycle. Many of them are filter feeders, meaning that they feed on things that flow past them in the water.


The sessile marine invertebrates attach themselves to a substrate and stay there throughout their life span. Corals belong to this group of immobile animals.

They live in warm shallow water with sunlight and little variation in salinity. Coral reefs are among the most diverse ecosystems in the world, but they are built by animals that are barely able to move at all.

Sea sponges

These are multicellular organisms with no distinct tissue or organs. They are mostly filter feeders and depend upon plankton as their food source. The common sea sponges include glass sponge and Venus’ flower basket sponge.

Sponges are simple multicellular organisms that can be found on the ocean floor. Their bodies consist of loose cells held together by a jelly-like material. They lack true tissues, organs and nervous systems.

Sponges attach themselves to rocks or other substrates and use flagella — whip-like structures — to circulate water throughout their bodies. Some species grow as large as 8 feet in diameter, but most are much smaller.

Sponges don’t have mouths, so they must rely on currents to bring food to them. They feed on plankton and other floating microorganisms. To reproduce, sponges release sperm into the water and wait for eggs from another sponge to be carried by the current and fertilize them.

The slowest animals in the world are the sea sponges. They can live up to 2,300 years and have been around for over 650 million years! Sea sponges are filter feeders that strain tiny particles of food from passing water currents with their hollow bodies.

The largest sea sponge in the world is found off the coast of British Columbia. It can grow to over six feet tall and weighs approximately 50 pounds.


These are filter feeders that use their gills for respiration and anchoring themselves to the substrate for movement.

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