The most important daily activity that animals go through to stay alive is gathering food. Food represents the fuel organisms use to carry out movement, respiration, reproduction, and growth. There is a wide range of techniques that animals use to get food, and I wanted to write this article on the four main feeding mechanisms that animals use.
- Filter feeders strain suspended food particles from large amounts of water.
- Substrate feeders live on or in their food.
- Fluid feeders consume the fluid of another organism to get nutrients to survive.
- Bulk feeders eat large pieces of food, usually from the source.
Please read on to learn more about each of these feeding methods.
Many marine mammals are filter feeders. Filter feeders, or suspension feeders, strain suspended food particles and tiny organisms from vast amounts of water. They pass the water over a filtering structure.
Various animals use filter-feeding to acquire food, and these animals come from several different phyla. Fish, crustaceans, bivalves, sponges, jellyfish, worms, and tunicates all use methods of filter-feeding. These animals range from the microscopic to the largest animal ever living on the planet, the blue whale.
Different animals have their mechanics for capturing food. Jellyfish, for example, create currents with their swimming legs that direct the water through hair-covered appendages. The hairs filter out the food particles.
Scallops, mussels, and clams are bivalves that siphon the water through body parts into gills, which combine physical filtration and mucus to capture particles.
Sea cucumbers and polychaete worms have appendages that capture particles drifting by in the current.
A prime example of large animals that filter feed is baleen whales. The blue whale, humpback whale, and minke whale have baleen plates. The comb-like baleen filters out fish, krill, and small invertebrates as large amounts of water. The whales then use their tongues to move the food down to their stomach.
Filter feeders typically live with other types of filter feeders and share the food available by specializing in different size ranges proportional to their size.
Filter feeders extract food from the water, including seston, zooplankton, and small fish. Smaller animals such as crustaceans and worms eat smaller food particles than larger animals such as whales.
If the food produced in the ecosystem runs out, then sessile life will run out of food.
Without filter feeders, marine ecosystems would have a significant gap as they play a major role in cycling energy. As they clear particles from the water, removing filter feeders by pollution or fishing can entirely change the look of vast swathes of the ocean. Without filter feeders, the water can get deoxygenated due to the increase in phytoplankton and zooplankton, causing the water to become murkier and dirtier.
Filter feeders are essential to remove particles from the water, converting them into energy and body tissue, which then becomes food for other organisms. Without filter feeders, many marine ecosystems would cease to function.
Substrate feeders live on or in their food source. Substrate feeders eat their way through their food. Some examples of substrate feeders are earthworms and caterpillars.
Earthworms are deposit feeders and survive on dead vegetation. As worms do not possess teeth or jaws, they cannot bite through anything hard. Earthworms survive on small particles which are sucked into their mouth. Small, decaying leaves, grassroots cuttings, and decaying roots can be found in the soil.
Earthworms get a lot of their nourishment by sucking in soil and digesting the organic particles it contains. Worms can eat up to 30 percent of their weight daily using substrate feeding.
Worms can also grab dead leaves, which they pull into their holes using suction. They do not eat them immediately but leave them to rot, sped up by the worm spreading their digestive juices.
Caterpillars that live on leaves will eat through them as they travel, leaving a trail of feces behind. Termites are another type of substrate feeder, as they can be found eating through wood.
If a mosquito has ever bitten you, you may have some idea of what fluid feeding is. Fluid feeders consume the fluid of another organism to get nutrients to survive.
Fluid feeders can feed on fluids such as nectar, blood, fruit juice, rotten fruit, honeydew, and sap flow.
Most fluid-feeding insects have mouthparts that consist of a proboscis to suck the organism’s fluids and mandibles to pierce through the skin. Others have a proboscis that can pierce and suck. Once the insect has penetrated the skin, the proboscis will use a sucking or lapping motion to extract nutrients. The fluid is ingested into the food canal.
Some of the most despised animals use fluid feeding to obtain their food and turn it into energy. The energy is used for reproduction, movement, and growth. Mosquitos, vampire bats, leeches, ticks, and spiders all use methods of fluid feeding.
However, not all fluid feeders feed on the blood of other animals. Butterflies drink nectar from flowers through straw-like tongues.
Hummingbirds are also called fluid feeders as they drink the nectar out of flowers. Hummingbirds use their long beaks to drink the nectar out of flowers. As the nectar is liquid, the hummingbird’s tongue traps liquid by changing shape as it moves in and out of the nectar. This is different from insects that use their proboscis to suck the juice out of organisms.
The vast majority of animals are classed as bulk feeders. Bulk feeders eat large pieces of food, usually from the source. Some examples of bulk feeders are humans, cows, snakes, and most bird species. Almost all animals over a few inches in size are bulk feeders.
The maximum amount of nutrients is ingested by eating all of its prey. Food can be swallowed whole or in pieces by chewing and swallowing. During digestion, the food is broken down into smaller particles, and the nutrients are extracted.
Some animals that are bulk feeders engage in group feeding, such as wolves. Hunting in groups allows them to find food faster as they minimize their search area and time. Hunting in groups also reduces the risk of predation while increasing the efficiency of capturing their prey.
It is not only terrestrial mammals that can hunt in groups—Dolphins herd fish near the shore before splashing them out of the water. Gray whales use bubble-net feeding to trap large amounts of fish. They work in groups to create a circle of bubbles, which traps the fish in the middle. The bubble net confuses the fish, which then swim to the surface. The whales will then catch them all in their mouth.
In the Sonora desert, groups of Harris Hawks will work together to hunt rabbits and cottontails. One bird will stay on a tree, while another will fly down to catch its prey. If it escapes, the hawk on the tree will fly down to try to see it.
Animals that are bulk feeders use many different methods to catch their prey. These include stalking and chasing their prey.