Communication in aquatic animals

Communication in aquatic animals is a fascinating way that creatures living in water talk to each other. Just like people use words or gestures to share ideas, animals in the water have their own special ways to send messages. These messages can be sounds, sights, touches, smells, or even electrical signals. When an animal sends a message, it’s trying to change the way another animal behaves. For example, a fish might make a sound to warn others about danger or show a special color to find a friend or a mate.

Water is very different from air, so animals that live underwater have developed unique ways to communicate. Unlike a horse that can smell scents in the air, fish need different methods to sense chemicals around them. Each kind of water animal has special organs to create and receive these messages, making their communication systems quite different from those of land animals.

Aquatic animals use communication for many important reasons, such as recognizing friends, finding mates, or defending their space. Sometimes, animals from different species can also “talk” to each other, especially if one is trying to stay safe from a predator or help another animal in a helpful relationship. Understanding these communication methods helps us learn more about how life underwater works and connects.

Aquatic animals modalities sensory systems terrestrial animals Interspecies communication

Modes of communication

Acoustic

Acoustic communication uses sound as a signal. Many aquatic animals, both invertebrates and vertebrates, use sound to talk to each other. Sound travels faster and farther in water than in air, so aquatic animals can communicate over long distances this way. For example, a blue whale can talk to another blue whale using sound across thousands of miles of ocean.

Fish can make sounds like whistles, grunts, and croaks using their swim bladder or fins. Frogs and toads can make sounds using special tissues. Seals and otters can produce sounds using their larynx. Some crabs and shrimp make noise by hitting or tapping on surfaces, and a special small fish called Danionella cerebrum makes a very loud sound for its size by using muscles to hit its swim bladder.

Aquatic animals can hear these sounds using special sensors. Mammals have external ears, but other animals have special ear holes or sensory hairs to detect sound.

Acoustic signals are used for:

• Getting together in groups
• Recognizing each other
• Attracting mates
• Showing they are ready to fight

Visual

Aquatic animals also use visual signals like movement, colors, and patterns to communicate. Coastal and ocean animals are more likely to use visual signals because it’s harder to see in murky or deep water.

Some fish and squids can control light patterns on their bodies to send messages. Dolphins have special markings that show their status. Crabs wave their claws to attract mates, and sea otters make head movements to show their reproductive status.

Visual signals are used for:

• Recognizing each other
• Attracting and choosing mates
• Showing they are ready to fight

Chemical

Many aquatic animals use special chemicals called pheromones to communicate. These chemicals can be dissolved in water or on the animal's body.

Crustaceans, fish, frogs, and dolphins all produce these chemicals in different ways. They can detect these chemicals using special sensors on their antennas, noses, or other body parts.

Chemical signals are used for:

• Attracting mates
• Showing they are ready to fight

Electrocommunication

Water is a good conductor of electricity, so some aquatic animals use electrical signals to communicate. Only fish can both send and receive these electrical signals. They have special organs that create electricity and can change the signals in different ways to send messages.

Fish can detect these electrical signals using special sensors on their bodies. Sharks have sensors on their snouts to detect these signals.

Electrical signals are used for:

• Showing they are ready to fight

Tactile

Tactile communication is touch and is only used over very short distances. It includes touching, rubbing, or even biting. Animals can feel these touches using special sensors on their skin or other body parts.

Tactile signals are used for:

• Mating rituals

Multimodal communication

Sometimes, animals use more than one way to communicate at the same time. For example, a frog might shake its feet and make sounds together to attract a mate. Using multiple signals can make communication clearer, especially in noisy or changing environments.

Interspecific communication

Interspecific communication is when animals from different species talk to each other.

Animals that might be hunted, like toads and guppies, often show signals to keep predators away. For example, a fire-bellied toad shows its bright belly when attacked, warning the predator that it is unsafe to eat. Guppies might look closely at a possible predator, showing they are alert and harder to catch, which can make the predator decide not to attack.

Sometimes, different animals work together for mutual benefit. One good example is the relationship between a goby fish and a snapping shrimp. The shrimp digs a burrow, and the goby fish stands guard at the entrance. If the goby sees danger, it flicks its tail to warn the shrimp, which then hides in the burrow. This helps both the goby, which gets a safe place to stay, and the shrimp, which can focus on building its home.