All living beings require energy to carry out their vital processes, and this is obtained from the nutrients that are consumed. The vast diversity of animal species that exist has different characteristics, among which are the way in which they feed, so that each group obtains and processes the food in a particular way, which is linked to their own anatomical and physiological conditions, but is also related to the habitat in which they develop.
An example of this is found in the so-called filter animals, which separate their food from an aqueous medium thanks to specialized structures for this purpose. On our site, we want to present you with information about these living beings, so that you know what this particular way of feeding consists of and which animals are included in this group.
What are filter feeders?
Filter animals receive this name because of their peculiar way of feeding. Filter feeding is usually carried out in aquatic environments and consists of capturing the food (which can be of both plant and animal origin) and then discarding the water so that only the prey can be eaten
What do filter feeders eat?
The diet of filter feeders can be very varied and in some cases more specific, and can be made up of:
- Plankton.
- Other animals.
- Floors.
- Algae.
- Bacteria.
- Remains of organic matter.
Types of filter feeders
Filter feeders can feed in a variety of ways:
- Active Animals: Some filter feeders remain active in the aquatic environment, constantly searching for sustenance.
- Sessile animals: we can also find sessile species that depend on water currents to pass through their bodies and thus catch the food.
- Animals that absorb water: in other cases, where the currents do not facilitate this process, the animals absorb the water and with this to the food, so that it is retained by the animal.
These species are present in various groups, from birds, mammals to a wide variety of invertebrates. They have a fundamental role in the food webs of ecosystems. In addition, they can play an important role in the clarification and purification of water, as is the case with oysters. Let's learn more about some examples of filter feeders.
Examples of filtering mammals
Among the filtering mammals we find baleen whales, which are the baleen whales, where we find the largest mammal on earth. These animals lack teeth, and instead have some flexible sheets made of keratin, which are called beards and are located in the upper jaw. Thus, the whale when swimming keeps its mouth open so that the water enters. Then, with the help of the tongue, it expels it, and the prey of the appropriate size are retained in the baleen, which are then ingested.
This group of animals consumes fish, krill or zooplankton, since they are carnivores, but whatever the food is, it must be presented in large quantities to make them interested in catching it. Baleen whales can feed at different depths, both on the bottom and on the surface.
Some examples of filtering mammals are:
- Southern Right Whale (Eubalaena australis).
- Blue whale (Balaenoptera musculus).
- Grey whale (Eschrichtius robustus).
- Dwarf Right Whale (Caperea marginata).
- Northern whale (Balaenoptera borealis).
Examples of filter feeders
Within the birds, we also find some that feed through filtration. Specifically, they are individuals that live most of the time in bodies of water and some of them can even be excellent swimmers. These can be:
- Exclusively filter-feeding birds: as is the case of flamingos.
- Birds with mixed feeding: others may combine this mode of feeding with other adaptive strategies, as is the case of ducks, which They have filtering structures, but they also have a kind of small "teeth" inside their beaks, with which they can directly hold the prey.
Among the foods filtered by these birds we can find shrimp, molluscs, larvae, fish, algae and protozoa. In some cases, they may ingest small amounts of mud to consume certain bacteria present in this sediment.
Examples of filter fish
In the group of fish, there are also several species that are filter feeders, and their food can consist of plankton, small crustaceans, other smaller fish and in some cases algae. Among filter fish, we find for example:
- Whale shark (Rhincodon typus).
- Basking shark (Cetorhinus maximus).
- Widemouth shark (Megachasma pelagios).
- Atlantic tarpon (Brevoortia tyrannus).
Generally, these animals let water enter through their mouth, which passes to their gills, where there are spiny structures that retain food. Once the water is expelled, they go on to consume the food.
Examples of filter-feeding invertebrates
Within invertebrates, we find the greatest diversity of filter-feeding animals, and as in the case of filter-feeding mammals, they are exclusively aquatic. Let's learn about examples of various filter-feeding invertebrates:
- Bivalves molluscs: within this group we find oysters, mussels and scallops. In the case of oysters, with the movement of their cilia, they suck the water and the food is trapped in a viscous substance that they have in their jowls. Oysters filter various contaminating agents that reach the water, processing them in such a way that they are no longer dangerous. For their part, the mussels feed on phytoplankton and suspended organic matter, also using cilia so that the marine fluid flows into the body.
- Sponges: Porifera are also filter-feeding invertebrates that have a body system very well adapted for this process, which has multiple chambers with flagella that retain organic particles, bacteria, protozoa and plankton in general, to feed. This group is also capable of storing polluting substances present in the water.
- Crustaceans: Two members of this group that represent the filter feeders very well are the krill and the mysidaceans, both of which are marine. Despite their tiny size, they are quite efficient at filtering and collecting suspended particles or phytoplankton, which they feed on. Filtration occurs through structures called "feeding baskets", where it is retained and then consumed.
Filter feeders play an important ecological role in aquatic ecosystems, since they renew the water through its filtering process, which is why the amounts of suspended particles in this medium are kept stable. In this way, their presence becomes very important within these spaces. In addition, as we have mentioned, they are highly relevant in trophic relationships, as they constitute one of the first levels of these complex plots.
