Cetaceans are a group of aquatic animals that include porpoises, dolphins, and whales. These animals have many similarities, like their sleek, streamlined bodies, carnivorous diet, and mating patterns. However, there are several differences between dolphins and whales.
What is the difference between dolphins and whales? Whales tend to be bigger than dolphins. In fact, blue whales are the largest animals on the Earth.
Key Areas Covered
1. Dolphins
– Definition, Features, Facts
2. Whales
– Definition, Features, Facts
3. Similarities Between Dolphins and Whales
– Outline of Common Features
4. Difference Between Dolphins and Whales
– Comparison of Key Differences
5. FAQ – Dolphins and Whales
– Answers to Frequently Asked Questions
Key Terms
Cetaceans, Dolphins, Whales
Dolphins – Facts and Features
Dolphins belong to a group called Odontoceti. They are divided into families like Delphinidae (oceanic dolphins), Platanistidae (Indian river dolphins), Iniidae (New World river dolphins), and Pontoporiidae (brackish dolphins). These animals are found all over the world. Most species live in warm tropical waters, but some prefer colder climates.
Dolphins come in different sizes – the small Maui’s dolphin is about 1.7 meters long and weighs 50 kilograms, while the massive orca can grow up to 9.5 meters long and weigh 10 tonnes. Males are often larger than females. Dolphins have sleek bodies and flippers for swimming. They are fast swimmers and can reach speeds of 29 kilometers per hour. They can leap up to 9 meters out of the water.
Dolphins are skilled hunters. They use their sharp, cone-shaped teeth to catch prey like fish, squid, and crustaceans. They don’t chew their food but break it into smaller pieces before swallowing. Their excellent hearing helps them navigate and hunt, even in deep or dark waters. Some species of dolphins can even survive without vision and rely solely on their hearing. They have a layer of fat under their skin, called blubber, which keeps them warm in cold water. Moreover, dolphins are social animals and communicate using clicks and whistles.
Whales – Facts and Features
Whales are large, fully aquatic mammals that live in oceans all over the world. Although dolphins and porpoises are sometimes called whales in a scientific sense, the term “whale” usually refers to the bigger species. Whales range in size from the small dwarf sperm whale, about 2.6 meters long, to the blue whale, which is the largest animal ever to live on Earth. Blue whales can grow up to 29.9 meters and weigh as much as 190 tonnes.
There are two main types of whales: baleen whales and toothed whales. Baleen whales, like blue whales and humpbacks, don’t have teeth. Instead, they use baleen plates—fringe-like structures in their mouths—to filter small food like krill and plankton from large gulps of water. Their massive heads (they can be up to 40% of their body weight) help them take in enormous amounts of water and food. They also have a strong sense of smell.
Toothed whales, such as sperm whales and belugas, have sharp, cone-shaped teeth for catching fish and squid. They rely on their excellent hearing, which works underwater and above it. Some species, like sperm whales, can dive incredibly deep to hunt their favorite prey.
These mammals are warm-blooded and have a layer of blubber under their skin to keep them warm. They breathe air through blowholes on top of their heads and must surface regularly. However, some species, like sperm whales, can hold their breath for up to 90 minutes. Whales have streamlined bodies and flippers for swimming. They can travel at speeds up to 20 knots and make a variety of sounds, including the famous songs of humpback whales.
Similarities Between Dolphins and Whales
- Both are warm-blooded animals.
- They breathe air through blowholes and need to come up to the surface to breathe.
- Both give birth to live babies and feed them with milk.
- Their smooth, sleek bodies help them swim easily in water.
- Most dolphins and whales are carnivores and eat fish, squid, and other sea animals.
- They are highly intelligent.
Difference Between Dolphins and Whales
Definition
- Dolphins are aquatic mammals in the family Delphinidae, while whales are large aquatic mammals in the infraorder Cetacea, divided into two main groups: baleen whales and toothed whales.
Size
- Whales tend to be bigger than dolphins. In fact, blue whales are the largest animals on the Earth.
Blowholes
- Whales have two blowholes on top of their heads, but dolphins have a single blowhole angled on top of their heads.
Teeth
- Some whale species do not have teeth, whereas dolphins have conical-shaped teeth.
Social Behavior
- Whales tend to be solitary or travel in small groups, whereas dolphins are highly social, traveling in large groups called pods.
Habitat
- Dolphins are usually found in shallow waters near the shore, while whales inhabit deep waters.
Holding Breath
- Whales can hold their breath much longer than dolphins. Some species can stay underwater for as long as two hours.
FAQ: Dolphins and Whales
1. How to tell a whale from a dolphin?
The most obvious physical difference between dolphins and whales is that whales are a lot bigger than dolphins. In addition, whales have two blowholes on top of their heads, but dolphins have a single blowhole.
2. Which whale is not a dolphin?
Scientifically, all whales, dolphins, and porpoises are classified as Cetacea. Within this group, called an infraorder under the order Artiodactyla, there are two subgroups: baleen whales and toothed whales. Dolphins are a type of toothed whale. They are essentially smaller whales, with killer whales (orcas) being the largest type of dolphin.
3. Are whales friendly to humans?
Modern research shows that whales are usually friendly. Today, when whales are seen, they often interact with humans in a social, curious, and friendly way.
4. Do dolphins like humans?
Yes, dolphins are often friendly and curious towards humans. They sometimes interact with humans in a playful way. They are known to approach boats and swimmers and show interest and playfulness.
Reference:
1. “Dolphin.” Wikipedia. Wikipedia Foundation.
2. “Whale.” Wikipedia. Wikipedia Foundation.
Image Courtesy:
1. “Dolphin Ocean” By safaritravelplus – (CC0) via Commons Wikimedia
2. “Black Whale in Ocean” (CC0) via Pexels
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