Coral is an important species in our oceans that supports thousands of different species of marine life. Many people perceive coral to be a plant, but this isn’t the case; it’s an animal or a collection of thousands of tiny animals, but can coral feel pain?
Coral can’t feel pain, at least not in a way that humans can measure or detect. Coral is made up of a collection of organisms called polyps. These polyps have no brain. Instead, they connect with a nerve net. As coral polyps lack a brain, they are unable to register pain.
Keep reading to learn more about corals, coral reefs, and their significant impact on the ecosystem. I’ll also explore where coral fits on the food chain, the varieties of coral reefs, and what you can do to keep coral reefs alive in the future.
Do Coral Have Nerves?
Corals don’t have a brain. They also lack many other features you would expect to find in animals, such as eyes and ears. So how do corals find food and other things they need to grow and live?
While corals lack a brain, they have a primitive nervous system, known as a nerve net. The nerve net has Chemoreceptor cells that detect amino acids and sugars. This allows the coral polyps to find food without any eyes or ears.
The coral’s nerve net can’t process as much information as ours, and that’s why corals can’t feel pain. However, they sense food and other things required for their growth.
Do Corals Have Nerve Endings?
As mentioned, corals have a simple nervous system called a nerve net. The nerve net acts as a brain for the coral as a means for the organisms to source food. Although coral has a nerve net, does coral have nerve endings also?
A nerve ending is a fine branch at the end of a neuron that connects with either another neuron or a muscle cell. The nerve net present in corals must be able to detect changes in their environment and send a message to the muscles within their mouth and digestive system to eat.
Corals have simple nerve endings that are capable of experiencing the world similarly to our sense of smell and taste. These nerve endings allow coral to sense their environment. Any changes felt by the coral are then transferred from nerve endings through the nerve net.
If you’re curious how to propagate coral in a reef aquarium, you can read my guide over here.
Do Corals Have a Brain?
As I’ve already mentioned, corals have a simplistic nervous system known as a nerve net. The nerve net allows corals to sense changes in their environment which in turn enable the animal to source food.
Corals do not have a brain. The coral’s nervous system does not connect into one centralized location, unlike the nervous system found in vertebrates. Instead, corals have neurons spread throughout their bodies in their nerve net.
A nerve net is a primitive nervous system that does not contain a brain. Nerve nets are found in a variety of vertebrates, such as jellyfish and corals. They are one of the most primitive forms of nervous systems in nature.
Neurons which are the cells in our nervous system that control thought and sense are scattered throughout a nerve net and not kept in a central location like a brain.
You may have heard of brain coral before. This is not to be confused with a species of coral that possesses a brain. Instead, it’s a species of coral that resembles a human brain. Brain coral is found in aquariums. You can also find brain corals in the wild in the Caribbean, Pacific, and Atlantic oceans.
Do Corals Have a Digestive System?
Coral has a stomach that allows them to digest small animals like zooplankton. They catch these tiny organisms with their tentacles. The tentacles then transfer the coral’s dinner to their mouth for digestion. They both eat and excrete through their mouths.
Corals have a couple of ways of finding food. The first is through a special relationship that most hard corals have with a type of algae called Zooxanthellae.
This algae live within the coral polyps and helps the organism convert sunlight to sugar for food. The coral then provides the algae with carbon dioxide and a protective home that ensures both organisms’ survival.
The second primary way that corals source food is through their tentacles. They can catch an array of small animals or organisms with their tentacles. Once the corals have acquired their food, they transfer it to their mouths, where it is digested.
Do Corals Eat Fish?
Corals consume small animals that they catch with their tentacles. Although these animals are usually microscopic, like plankton, some coral species eat larger organisms.
Corals with large polyps like Catalaphyllia eat small fish on occasion. Larger polyp species also eat crabs and sea snails. However, corals aren’t exactly agile predators, so their prey is usually sickly or slow in the first place.
For a long time, scientists believed that corals with large polyps were more aggressive predators than smaller polyps. But we now know that corals with smaller polyps seek live food more aggressively for sustenance.
What Eats Corals?
While corals are predators, they’re also on the menu for a variety of animals. A host of marine life feeds off of live corals as a source of nutrition.
Worms, sea snails, starfish, and some crabs are all known animals that feed on coral. Some varieties of fish also eat coral polyps. In particular, most of a parrotfish’s diet consists of corals and the algae that grow around them.
The crown-of-thorns starfish eats a lot of coral. These starfish prefer hard corals but will quickly tick into soft corals if there are no hard coral species nearby.
These starfish pose a threat to already struggling coral reefs. In particular, the Great Barrier Reef in Australia is researching methods to prevent these starfish from devastating the reef.
What Are the Main Types of Coral Reefs?
There are about six thousand species of coral around the world. These corals come in just almost every shape, size, color, and design that you can think of. Similar to coral, reefs also come in a variety of forms. Coral reefs form in different waves and have other unique features.
Here are the four main types of coral reefs that you’ll find around the world:
- Fringing Reefs
- Barrier Reefs
- Atoll Reefs
- Patch Reefs
The first type of coral reef that I’ll explore today is the fringing reef. Fringing reefs are the most common types of coral reefs. They grow along coastlines around islands and large landmasses. These reefs grow parallel to the coast and are usually separated by a shallow lagoon.
Barrier reefs earned their name as they can reach the water’s surface and form a block or barrier above the water. They grow similarly to fringing reefs but have a deeper and broader lagoon separating the reef from the coast. The Great Barrier Reef is the largest and most famous coral reef in the world.
Unlike barrier and fringing reefs, atolls are usually found out at sea away from the shoreline. Atolls typically form when islands surrounded by fringing reefs are swallowed into the sea. The reefs continue to grow and develop a ring around where the island once was. As a result, protected lagoons form inside the atoll.
The final type of coral reef is patch reefs. Patch reefs usually develop between fringing reefs and barrier reefs. They form from the bottom of the ocean and grow upwards. They rarely reach the surface and can fluctuate in size.
How Old Are Most Coral Reefs?
Corals have been around for a very long time. Scientists believe that coral reefs date back to at least 240 million years ago, long before the dinosaurs went extinct. But how old are the coral reefs?
Coral reefs are typically between 5,000 and 10,000 years old. Their age is measured using Radiometric dating as they secrete a hard external skeleton that absorbs radioactive isotopes from seawater. These isotopes enter radioactive decay, which is calculated to determine the animal’s age.
Carbon-14 dating is another method used to measure the age of a coral reef. All living organisms contain carbon. After death, carbon slowly decays from the organism. Carbon dating measures the amount of carbon within the organism to estimate its age.
Can Coral Hurt Humans?
Coral can hurt humans in numerous ways. Hard corals are solid and can be jagged; this can cause cuts and injuries to snorkelers and divers. Some species of corals contain palytoxin that can be fatal to humans. Coral reefs are also home to numerous dangerous species of marine life.
Species of coral called zoanthids contain a harmful poison known as palytoxin. Palytoxins can cause several adverse effects for humans if they come in contact with this toxic substance. However, palytoxin poisoning is rare.
The common source of palytoxin poisoning is from eating contaminated seafood. However, palytoxin poisoning may occur when handling corals. This is problematic as some species of zoanthids are commonly sold in aquariums.
Palytoxin poisoning may cause symptoms ranging from nausea to death. If you have come in contact with coral and show signs of poisoning, seek medical care immediately or consult poison control.
Every year surfers, divers, and snorkelers are injured from coral cuts and scratches. The brutal abrasive nature of hard corals can result in deep wounds if you accidentally contact them. On top of this, there is a high risk of infection from coral cuts. Therefore first aid treatment and a potential hospital trip may be required if corals scratch you.
Coral reefs are home to a wide array of marine life. The variety of life facilitated by coral reefs makes for spectacular colorful scenes when diving. However, as always, when dealing with wildlife, this comes with some risks. Sea urchins are one species that you’ll nearly always find near coral reefs. Sea urchins can cause nasty stings if you come into contact with them.
The variety of fish found near coral reefs also attracts predators like sharks. While shark attacks are rare, they can have life-changing outcomes for anyone involved. As a result, coral reefs pose numerous safety risks for humans.
How Do Humans Damage Corals?
You may have heard pleas from different organizations and conservationists about the conditions of coral reefs. Coral reefs are in rapid decline around the globe, with the Great Barrier Reef decreasing in size by as much as 50% in recent years. How do humans damage corals?
Here are a few ways that humans cause harm to corals:
- Harmful fishing practices
- Collecting wild coral
- Coastal developments
- Co2 usage which contributes to rising water temperatures.
Luckily for coral, we humans can not eat them.
How Can You Protect Coral Reefs?
Coral reefs are in desperate need of human intervention to prevent their demise. While you may not be able to change harmful fishing practices or global fossil fuel usage, there are some ways that you can help to protect coral reefs to ensure their survival for future generations.
Here are a few ways that you reduce your harm and protect coral reefs:
- Recycle when possible.
- Avoid using fertilizer when possible.
- Use eco-friendly transport.
- Reduce your energy usage.
- Don’t touch or harm coral in the wild.
Adopting these environmentally friendly practices can minimize the harm that you cause to the environment. This can slow the rate of climate change which can prevent water temperatures from rising. This will prevent the bleaching effect in coral which is killing large areas of reefs.
There are over 6,000 species of coral in the world. Coral polyps are brainless organisms that are unable to feel pain. This is because coral has a primitive nervous system called a nerve net that cannot register pain. However, the nerve net is capable of sourcing food for the coral.
Coral reefs are an integral part of the ecosystem. They provide shelter and food for an array of wildlife. Millions of humans also benefit from coral reefs both directly and indirectly as people depend on corals for fishing, and coral reefs protect coastlines from storms.
- Toronto Zoo: Live Reef Corals
- Florida Keys National Marine Sanctuary: Corals get their food from algae living in their tissues or by capturing and digesting prey
- CSIRO ECOS AU: The race to stop crown-of-thorns starfish destroying the Great Barrier Reef
- Coral: Types of Coral Reef Formations
- Ocean Explorer NOAA: Coral Age Dating
- SAHealth: Palytoxin Poisoning