Usually, a characteristic that we associate with animals is their ability to move from one place to another, since, through displacement, they manage to carry out many of their vital functions, such as feeding, reproducing, escape predators and even migrate in some cases.
However, not all animal species have this ability, but there are certain animals that do not move. Although they can make certain movements to achieve, for example, feed themselves, they do not move from one place to another or they do so in a very limited way. Read on and discover these animals that don't move in this article on our site.
Corals
A classic example of animals that do not move are corals, which belong to the phylum Cnidarians and to the class Anthozoa. Many species of corals form reefs, which are the typical colonies consisting of calcareous skeletons produced by the various polyps that, in large numbers, make up the colony. These individual polyps are genetically the same.
Each polyp is an animal with the shape of a sac and a single opening, located in the upper central area, which corresponds to the mouth. In it there are a series of tentacles that, in some cases, they use to hunt and to feed.
Corals can reproduce sexually and asexually. In sexual reproduction they have a larval phase in which they are mobile, although they search the marine substrate for a suitable area to settle and form the colony, which will be immobile for the rest of its life.
Sponges
Sea sponges are a group of aquatic animals that belong to the phylum Porifera. The great majority are marine and very few are found in fresh water. Like all the animals in this article, they are characterized by being sessile, that is, they are immobile animals. In addition, porifera have the peculiarity of not forming tissues On the contrary, they are made up of cells that are capable of transforming into various cell types according to the needs that the organism has. animal.
Unable to go after food, they use their whole body to nourish themselves. This is formed by a series of pores through which the water enters, which circulates to a specialized chamber, made up of particular cells, where the filtration of the liquid takes place and the retention of the nutrients that the animal requires and that will be processed. or digested at the intracellular level, since sponges lack a digestive system Finally, the water leaves the body through its only opening, located at the top.
Anemones
Sea anemones are another example of animals that don't move. They belong to the phylum Cnidarians and to the class Anthozoans. Their sessile life takes place on various types of marine substrates, which can be rocks, sand or even the shells of some animals.
The body of anemones is cylindrical in shape and has a base without a hole that is fixed to the substrate. At the other end is the animal's mouth, surrounded by various tentacles. These latter structures are endowed with organelles that contain specialized cells that produce a stinging toxic substance, which can be used for defense or to capture prey.
These cnidarians have a wide maritime distribution throughout the world, found in various temperature ranges. They can also live at different depths and are even able to survive out of the water thanks to a temporary protection mechanism that allows them to fill up with liquid and retain it so as not to dry out.
Barnacles
Barnacles belong to the group of crustaceansThey are marine animals that in their adult lives are characterized by being totally sessile, living strongly attached to various substrates, such as rocks, although they even have the ability to adhere to different boats, which is inconvenient when the number of barnacles is numerous. since they interfere with the speed of navigation. Some of these animals occupy the intertidal zone, which means that they can be exposed to drying out by the action of the wind.
One of its main characteristics is that it is covered by a calcareous-type shell, from which come structures known ascirros that they use to retain the nutritious particles with which they feed. However, some depend on the movement of water, more than on their cirrus clouds, to be able to feed, since they manage to nourish themselves through the circulation of the liquid.
Moss animals
This group corresponds to the phylum Bryozoa, which is made up of various species of animals that do not move in their adult phase and that form coloniesThey are sometimes known as moss animals, given their similar appearance to these plants. They live on various types of substrates, such as rocks, sand and even some types of algae. Most of the species are marine, although there are a few that inhabit freshwater.
As for feeding, they feed by filtration and make use of the presence of a crown of tentacles that produces a current of water so that the food, consisting mainly of phytoplankton, reaches the cilia, which are responsible for trapping the nutrients that will later be carried to the animal's mouth. In this article we talk about other filter animals.
Blue Mussel
The blue mussel (Mytilus edulis) is a species of bivalve mollusk which, although in its early stages of life it has the ability to mobilize, when it is a well-developed juvenile adult, it is permanently attached to a substrate. It is found in depths of between 5-10 meters, but also frequently in intertidal zones.
A peculiarity of these animals is their ability to bear freezing temperatures for a few months. They are filter feeders of phytoplankton and zooplankton. When they settle permanently they do so by clumping together, so it is common to see groups of these animals, which is detrimental to the older individuals, who end up suffocated by the young that cling to them.
Do you want to know more molluscs? Read our article Types of molluscs - Characteristics and examples.
Sea Feathers
Despite the name of this group of cnidarians, not all of them are shaped like a bird's feather. Specifically, the comparison can be established with those belonging to the suborder Subselliflorae. Marine feathers, although they can change location, are really sessile, as they anchor in the sandy substrate with the base of the body and remain there, positioning themselves at favor of the currents and forming colonies.
Their bodies are formed by polyps that are specialized in various functions, for which they undergo changes. These functions include attachment to the substrate, feeding and reproduction. A peculiarity of some species of marine feathers is the display of beautiful colors, as well as their ability to bioluminescence, that is, to emit visible light, like these other animals that glow in the dark.
