Whales are divided into two suborders, baleen whales and toothed whales. While both belong to the Cetacean order, sharing common ancestry and certain characteristics, they represent distinct branches on the evolutionary tree, leading to fascinating differences in their biology, behavior, and ecological roles.
Contrary to what you would expect, dolphins are actually a part of the toothed whales group. This group also includes orcas, also known as killer whales.
Despite their differences, both whales and dolphins play vital roles in maintaining the delicate balance of the marine ecosystem. Understanding their unique adaptations and the challenges they face is crucial for their conservation and for appreciating the remarkable diversity of life in our oceans.
Credit: Seiji Seiji on Unsplash (left), Elias Levy (right)
Whale vs. Dolphin: Main Differences
While both whales and dolphins share a streamlined, torpedo-shaped body plan adapted for aquatic life, key differences distinguish them. Some species, like sperm whales, feed on larger prey and have diets more similar to dolphins.
Appearance: Dolphins and whales have different body shapes. Dolphin bodies are leaner with longer beaks, while whales are bulkier-looking. Additionally, all dolphins have relatively pronounced dorsal fins, while most whale species have small or no dorsal fins.
Size: Whales, particularly baleen whales, can reach colossal sizes, with some species exceeding 100 feet in length. Dolphins, on the other hand, are generally smaller, with most species ranging from 4 to 30 feet.
Habitat: Whales can be found worldwide, in all oceans regardless of temperature. Often, they spend the summer months at higher latitudes and then spend the next months traveling and breeding. Dolphins prefer to live in open oceans and warm, temperate waters. Some species even live in reverse.
Diet: Dolphins are opportunistic feeders and possess conical teeth for grasping and tearing prey. They choose prey that is easily available rather than being too selective in their diet. They usually eat fish, shrimp, small octopuses, and jellyfish, while whales are generally filter feeders. They feed on plankton and krill and have baleen plates, fringed structures in their mouths used to filter food from the water.
Reproduction: Dolphins and whales are matriarchal in their social organization, allowing males to mingle with females only during the mating season. The most dominant males share most of the reproductive opportunities. The mating season for dolphins and whales occurs in warmer seasons.
Social Behavior: Dolphins are highly social animals, typically living in pods that can range in size from a few individuals to hundreds. While some whale species, like orcas, also live in complex social groups, others, particularly baleen whales, are often solitary or form smaller, less permanent groups.
Who Would Win?
In a face-off between a whale and a dolphin, the whale emerges victorious almost every time. The sheer difference in size is like comparing a school bus to a motorcycle – the whale’s mass and power are simply overwhelming.
A single bite from a toothed whale or a blow from a humpback’s tail could easily crush a dolphin. While dolphins are incredibly agile and fast, able to outmaneuver larger creatures, they can’t escape a whale’s reach forever. Even a coordinated attack from a large pod of dolphins might only harass, not defeat, a whale.
The exception? The orca, or killer whale. Despite their name and dolphin-like appearance, orcas are the largest dolphins and skilled hunters known to take down even large whales. Ultimately, while dolphins are remarkable, in a head-to-head against a whale, size and power reign supreme.
Whales
Whales are a diverse group of marine mammals. They can be found worldwide in warm and cold oceans. There are eight living families of whales, including the right whales, grey whales, belugas, narwhals, and sperm whales. They are open-ocean mammals meaning that they spend the entirety of their lives in the open ocean (breeding, feeding, and raising their young).
Worldwide, there are two types of whales—baleen and toothed. There are seventy-seven species of toothed whales and only fifteen species of baleen whales. Some of the incredible whale species found in the earth’s oceans include:
- Blue Whale
- Bowhead Whale
- Right Whale
- Humpback Whale
- Fin Whale
- Grey Whale
Toothed Whales:
- Sperm Whale
- Dwarf Sperm Whale
- Beaked Whale
- Beluga Whale
- Long-finned Pilot Whale
- Narwhal
All dolphin species, including the orca, belong to the toothed whale group.
Whales have a unique way of communicating. They speak through what is known as “whale song.” They create whistles and clicks that can travel for miles. These can generate an incredible 20,000 watts of sound.
Whales are also regarded as one of the most intelligent species on Earth. They can grieve, teach and learn, cooperate in groups, and understand human behavior.
Whales have flippers on either side of their body, (sometimes) a small dorsal fin, a fluke or tail fin of varying size, and small eyes and ears.
Whales are also known for their blowholes which allow them to breathe at the water’s surface. The smallest whale species reach less than ten feet in length, while the largest species can be up to or more than 100 feet long. The blue whale is famously the largest mammal to ever live on Earth. Blue whale calves are around three tons and 25 feet long when they’re born.
Habitat
Whales live around the world. They are generally solitary creatures that spend much of their time swimming alone or in small groups. They are also known for their long migrations, which can take them thousands of miles across the ocean.
Various species can be found in both warm and cold water. Some species, like the humpback whale, migrate to and from their food supply to breed and raise their young, while others stay in the same region year-round. Unlike dolphins, whales only live in salt-water environments.
Diet
Whales have diverse feeding strategies. Baleen whales, like humpbacks and blue whales, are filter feeders. Instead of teeth, they have baleen plates that act like giant sieves, trapping tiny crustaceans like krill and copepods, plankton, and other small marine animals from huge gulps of water.
The plankton-eating baleen whale has two blowholes, whereas whales with teeth have just one. They also can echolocate. This means they emit various clicking sounds through the water and wait for the rebounding sound waves to indicate where their prey is.
Toothed whales, like dolphins and sperm whales, hunt using sharp teeth and echolocation. Sperm whales dive deep for giant squid, while orcas cooperate to hunt fish and even other whales.
Reproduction
Whales have a fascinating reproductive process characterized by long gestation periods and dedicated maternal care. After internal fertilization, females undergo a pregnancy lasting anywhere from 9 to 17 months, depending on the species. This extended period allows for significant fetal development, resulting in a well-developed calf being born tail-first to prevent drowning.
Mothers are fiercely protective and nurse their calves for months, providing nutrient-rich milk crucial for rapid growth. Many whale species exhibit complex social structures that influence breeding, with elaborate courtship displays and vocalizations playing a key role in finding a mate.
Threats
Historically, whales are one of the most threatened species on earth. Throughout the 18th and 19th centuries, whale hunting was a widespread and incredibly detrimental practice that was responsible for the near-extinction of various whale species. Some countries, like Norway, Iceland, and Japan, still engage in varying degrees of whale hunting. But, throughout much of the world, bans are in effect in an attempt to allow populations to recover.
Whales are also threatened by human-caused climate change, pollution, trawling, and habitat destruction.
Dolphins
All species of dolphin and porpoise are part of the toothed whale suborder. This includes the orca or killer whale. They exhibit complex communication skills, using a combination of whistles, clicks, and body language to coordinate hunting, navigate, and maintain social bonds.
Today, there are forty-nine different species of dolphin and porpoise in the world’s oceans. They can be divided into six families. The largest of these is the oceanic dolphin family. Some of the many species of dolphin include:
- Bottlenose Dolphin
- Short-beaked Common Dolphin
- Chinese White Dolphin
- Atlantic Humpbacked Dolphin
- Indo-Pacific Bottlenose Dolphin
- Killer Whale (Orca)
- Long-finned Pilot Whale
- Hector’s Dolphin
Habitat
Dolphins spend most of their lives near the surface of the ocean. As mammals, they need to return to the surface to breathe, and they do so through their blowholes positioned at the top of their heads.
Despite their reputation for speed, dolphins’ typical swimming speeds are surprisingly moderate, reaching a maximum of roughly 3 meters per second during routine activity.
Dolphins are highly social animals that often travel in large groups or pods.
They live in all the world’s seas and oceans, around coastal areas, or even in shallower water. But, unlike whales, most species of dolphins prefer warmer waters.
Diet
Dolphins are opportunistic feeders and often utilize herding to gather together groups of fish. When the fish are herded into a small group, commonly known as a bait ball, individual members can swim through the group of fish, feeding as they please.
Bottlenose dolphins and orcas have also been known to strand their prey on a beach to feed on it.
They possess cone-shaped teeth. Common prey for dolphins include fish, squid, and jellyfish. Since dolphins are found around the world, they typically eat whatever fish they come upon. This can depend on the time of year.
Dolphins, unlike baleen whales, make use of echolocation while hunting. This allows them to hunt via reflected sound or echoes. They can use this to find prey and learn important information about the size and other characteristics.
Reproduction
Dolphins, known for their intelligence and social nature, also share a unique reproductive strategy. Like whales, they reproduce sexually with internal fertilization. Female dolphins experience a gestation period of around 12 months, giving birth to a single calf, usually tail-first.
Maternal care is paramount, with mothers nursing and protecting their young for several years.
Dolphin societies are complex, and breeding is often influenced by social hierarchies and elaborate courtship rituals, which can include synchronized swimming, vocalizations, and gentle touches.
Threats
Like all species of whale, dolphins are at threat from hunting practices, trawling, entanglement with fishing gear (also known as by-catch), pollution, habitat degradation, and more.
Habitat degradation, driven by pollution, coastal development, and noise pollution from shipping and seismic surveys, disrupts essential behaviors like foraging and communication.
Targeted hunting in some regions and the indirect impacts of overfishing, depleting their food sources, add to their plight. These threats highlight the urgent need for conservation efforts to protect these charismatic marine mammals.
Ocean Insights: Hear From Our Experts
By Hamna Faizan
Marine Life Researcher and Lecturer, with an MSc in Zoology
FAQs
Do whales eat dolphins?
No, most whales are filter feeders. But killer whales (which are a kind of dolphin) have been known to eat dolphins. They are one of the ocean’s most formidable predators.
Do whales and dolphins get along?
There is some evidence that dolphins and whales get along. Generally, neither species is a threat to the other (besides orcas). They are both highly intelligent species and share many of the same needs when it comes to safe habitats.
Can whales and dolphins interbreed?
While they share a common ancestor, millions of years of evolution separate them. They’re too genetically distinct to interbreed, much like humans and chimpanzees. Think of it like this: a dolphin trying to breed with a blue whale would be like a chihuahua trying to breed with an elephant!
Are dolphins smarter than humans?
No, dolphins are not smarter than humans. But, they do display a level of intelligence that far outranks most other non-human species. They can learn, communicate with humans, grieve, display empathy, and form relationships with humans.
Can whales and dolphins drown?
While perfectly adapted for aquatic life, they still need to consciously breathe air. Entanglement in fishing gear or a powerful impact can prevent surfacing, leading to drowning. This is a tragic reminder that even creatures most at home in the water are vulnerable to human-caused threats.
