|Scientific name||Cetacea||Weight||135–200,000 kilograms (0.14–200 tons)|
|Pronunciation||weyl.||Length||2.6–30 meters (8.5–100 feet)|
|Classification||Mammalia, Artiodactyla, Cetaceamorpha||Location||Worldwide|
Whales are evolutionary marvels.
These living behemoths are the largest inhabitants of Earth’s oceans worldwide and are fully adapted to life in the open ocean.
In fact, they’re so adapted to aquatic life that most people even forget they’re not fish or related to them.
Whales are mammals.
They are descendants of land-dwelling animals that returned to the ocean several million years ago.
The cetaceans have come a long way since their days as four-legged ungulates that lived on the fringe of land and sea.
Today, whales are the largest animals on Earth, with the blue whale being the largest animal, both living and extinct.
In addition to their size, whales also show several other remarkable adaptations and occupy various ecological niches due to their diversity and abundance.
In this article, we’ll explore some of the attributes of this unique group of mammals, detailing various aspects of their life.
Taxonomy and Classification
The term “whale” can be used for any of the 90 species of mammals in the Cetacea infraorder.
Members of this group include the more recognizable whales, dolphins, and porpoises.
However, the name applies more specifically to the larger cetaceans that are at least three meters (10 feet) long.
This criterion excludes porpoises and dolphins but includes the dwarf sperm whale (Kogia simus), despite being less than three meters long due to its resemblance to the sperm whale.
So, while they’re technically whales, dolphins and porpoises are typically not called by that name.
The whale family is divided into two groups: toothed (Odontoceti) and baleen whales (Mysticeti).
As the name suggests, toothed whales have teeth, while baleen whales have large fibrous plates in their mouths instead of teeth.
This plate is made from keratin material and filters tiny zooplankton and small fish from the seawater into their mouths.
Cetaceans belong to the order Artiodactyla.
Members of this group are also known as even-toed ungulates because they bear their weight on two toes instead of five.
The closest living relatives of the whales within this order are the hippopotamuses.
Whales are among the oldest living mammals.
They evolved about 56 million years ago and gradually transitioned from land-dwelling animals to a fully aquatic lifestyle over the course of the Eocene Epoch.
The transition from land to sea involved several adaptations, including changes in their limb structure, the complete loss of their hind limbs, and the development of flippers and tails for efficient swimming.
The baleen and toothed whales split off from the same common ancestor about 34 million years ago.
There are 15 living species of baleen whales, three species of sperm whales, 23 beaked whales, and two members of the monodontidae family (narwhal and beluga).
Although they’re mammals, whales have streamlined bodies reminiscent of other aquatic animals.
Their general appearance varies, depending on the species in question.
All whales have forelimbs modified into giant flat flippers.
They also have a horizontal tail, divided into two broad sections known as flukes.
They all have elongated bodies with a head that transitions smoothly into a fusiform trunk and a well-defined tail.
Their eyes are located on the side of their heads.
All whales have at least one blowhole on the top of their head, which they use for breathing (the baleen whales have two blowholes).
Whales vary in size as well.
The largest of them is the blue whale, which can grow to lengths of up to 100 feet (30 meters) and weigh up to 200 tons.
That’s about the same weight as 33 elephants!
This size makes them the largest marine animals and the largest animals to have ever lived.
The smallest whale is the 2.6 meters (8.5 feet) sperm whale, which weighs only 135 kilograms (298 pounds)
Cetaceans have smooth, rubbery skin with a thick layer of blubber.
This layer of fat helps to keep them warm and also keeps their massive bodies buoyant in the water.
Their coloration varies by species, but most whales are predominantly gray or black on their dorsal side.
Some species, like the blue whale, have a bluish-gray coloration.
Their ventral side is often a lighter color.
Some species, such as the humpback whale, have distinctive patterns on their flukes, which is helpful in identifying them.
Habitat and Distribution
Whales are found worldwide.
They live in every ocean on Earth, from the temperate and tropical waters around the equator to the freezing Antarctic and Arctic oceans.
Some whale species have their populations restricted to particular oceans or regions.
The North Pacific right whale, for instance, is only found in the waters of the North Pacific Ocean off the coast of California and Alaska.
On the other hand, some species, like the humpback whale, are known for their long-distance migrations, which extends their range quite significantly.
Bowhead whales and beluga whales are adapted to cold polar waters.
Consequently, they’re more commonly found in the cold waters of the Arctic and Antarctic regions.
Most whale species live in the open ocean.
Species like the blue whale, fin whale, and humpback whale are adapted for life in deep waters.
However, a few species, like the killer whale, frequent shallower waters along the coastlines where their preferred prey are more abundant.
Most whales dive to an average depth of about 100 meters (328 feet).
However, a few species are capable of diving much deeper.
For instance, the Cuvier’s beaked whale has been found at depths of up to 2,992 meters (9,816 feet).
This makes them the deepest diving mammal species on Earth.
Behavior and Social Structure
Although they’re fully marine, whales don’t breathe with gills like fish do.
This means they have to return to the surface frequently for air.
They have very efficient lungs which can retain oxygen for long periods.
They take up air and breathe out through their blowholes when they come to the water’s surface.
Most whales can hold their breath underwater for up to 60 minutes, but some species can hold their breath for even longer.
This allows them to dive for long periods without surfacing.
They may surface every three to five minutes when cruising near the surface but can dive longer when hunting for prey.
Despite their size, whales are efficient swimmers.
Some species can swim very fast compared to other marine mammals, like seals.
The fin whale, for instance, can reach speeds up to 47 kilometers per hour (29 miles per hour), while sperm whales go at about 35 kilometers per hour.
Blue whales typically cruise at about five miles per hour but can accelerate in short bursts of up to 20 miles per hour in certain situations.
Whales are mostly active at night or during the early hours of the day.
This means they’re either nocturnal or crepuscular.
However, they may also be active during the day during certain seasons.
For instance, whales are less active at night during the summer months because prey are more accessible during the day.
Because of the way their brains are wired, whales have to stay active all the time.
They do not sleep like other mammals because their brain has to be conscious for them to breathe.
Some species take power naps for short periods, while others have been known to sleep with only one side of their brain at a time while the other side stays active.
Cetaceans are not highly territorial animals.
Their range typically overlaps with that of other individuals, and they may also interact with other animal species.
Some species prefer specific feeding grounds and maintain migration routes, but they do not defend these aggressively.
Many whale species exhibit seasonal migrations.
For instance, humpback whales have their feeding areas in the poles while they breed in tropical waters.
This means migrating thousands of miles every year between these areas.
The different cetacean species exhibit a wide range of social behavior.
Male sperm whales, for instance, are solitary for most of the years except during mating season, where they form temporary groups.
Some species, like the gray whales, also form small stable groups of about three to 16 individuals, while others form even larger herds with complex social structures.
Killer whales are among the most social marine mammals.
They live in matrilineal groups (maternally related individuals) with a strong social hierarchy.
There’s evidence of coordinated hunting efforts with complex strategies within these social groups.
Diet and Feeding
Whales are generally carnivorous and predatory.
However, the two whale families, baleen whales (Mysticeti) and toothed whales (Odontoceti), have unique diets and feeding habits.
Baleen whales are filter feeders.
They have fibrous plates known as “baleen” in their mouths.
This acts like a filter that collects small fish, krill, plankton, and crustaceans from seawater.
As they swim through the water with their mouths open, baleen whales swallow large amounts of water, which they sieve with the hair-like structures on their baleen.
The baleen traps prey while the excess water is expelled.
Blue whales, the largest whale species on Earth, eat up to four tons of krill daily.
The toothed whales have a different feeding strategy.
They’re active predators with teeth, which they use to hunt and capture various prey.
Toothed whales have a more diverse diet, which may include fish, squid, octopuses, and other marine mammals.
They are apex predators known to target seals, sea birds, sharks, and even whales significantly bigger than themselves.
The toothed whales use different strategies to hunt prey.
While most species are solitary hunters, orcas exhibit complex cooperative hunting strategies.
Some whales also use a strategy known as bubble-net feeding.
This involves blowing bubbles from their blowholes cooperatively.
The bubbles trap the prey, making it easier for the whales to catch and eat them.
Reproduction and Life Cycle
The mating and reproductive behavior of cetaceans may vary slightly for the different species.
Most of them have specific mating seasons, and they may migrate for long periods to their preferred mating grounds.
The humpback whale is the only whale species whose migrating pattern is well documented.
They leave the Arctic and Antarctic regions where they live to the warmer tropics to mate and will also return to calve and raise their young.
Unlike other aquatic mammals that tend to return to land to mate and calve, whale species are fully aquatic.
This means they mate and give birth to their young in the water.
Some species have elaborate courtship displays and other mating behavior.
For instance, humpback whales have complex acrobatic courtship displays such as breaching and tail-slapping.
The narwhals have a long, spiral tusk, which they use to attract mates and establish dominance.
Whales are placental mammals, which means the females (called cows) carry their young in their bodies.
The embryo receives direct nourishment from the mother during pregnancy.
Whales have a long gestation period, which may range from about nine to 17 months, depending on the species.
Female bowhead whales have the longest gestation period, which may be as long as 23 months.
Whale calves are born tail first to keep them from drowning when they emerge from the mother’s body.
The cow produces fat-rich milk, which it uses to feed the calves.
Whales produce only one offspring with each birth.
The young calf is fully dependent on the mother and will remain with her for one to two years until fully mature.
Calves become independent at about two years old, but sexual maturity is not achieved until they’re about seven to 10 years of age.
Whales have a long lifespan that can last anywhere between 20 and 100 years, depending on the species.
Some species, such as the bowhead whale, may even live for up to 200 years!
This makes them the longest-living mammal on the planet.
Ecological Role and Interactions
Whales are carnivorous predators.
This puts many of the large whale species at the very top of the marine food chain.
Their impact on prey populations depends on whether they’re toothed or baleen whales.
The baleen whales eat tiny organisms such as plankton and krill, while the toothed whales target larger animals such as fish, squids, sharks, and marine mammals.
Their large size means they have to eat a lot of food to survive, which has a tremendous impact on prey populations.
Maintaining a balance in phytoplankton populations is particularly important.
They are the foundation of the entire marine food web, and any instability in their population can destabilize the food web.
Whales also interact with other animals within their ecosystem.
They have been observed hunting cooperatively with other species of whales or some pinnipeds (seals).
One of the most notable mutualistic relationships formed by whales is their interaction with barnacles.
These tiny marine organisms often attach themselves to the skin of whales.
Although they look like parasites, barnacles don’t harm whales in any way.
The whale’s body provides a stable surface for them to live on, and the barnacles may serve as a protective armor for some whale species against predators.
Whales sometimes fall prey to larger predators within their ecosystem.
Larger baleen whales are typically not attacked by predators due to their size, but sharks and killer whales can kill the smaller whales.
Whales contribute to the overall productivity of the marine ecosystem.
Due to their immense size, simply swimming from the ocean depths back to the surface aids the circulation of nutrients and nitrogen in the water.
This phenomenon is known as the “whale pump.”
Whales also defecate near the ocean surface, and their excrement, rich in nitrogen and iron, serves as food for phytoplankton.
Similarly, when whales die, their bodies sink to the sea bottom.
Whale carcasses (also called whale falls) support a rich assemblage of animals.
A whale fall may serve as a favorable habitat for up to 407 species of marine animals.
The deterioration of whale carcasses happens in three stages.
This may last for several decades, and each stage supports different groups of animals.
Conservation Status and Threats
The population and conservation trends vary for the different whale species.
Some whale species, such as the bowhead and humpback whales, are listed as “least concern” on the IUCN Red List of endangered animals.
This means their population is flourishing, and they are at no risk of extinction.
However, a few species are not so lucky.
The blue whale, for instance, is currently classified as endangered, while the Rice’s whale and the North Atlantic whale are critically endangered.
These species are currently on a decline and are at risk of extinction in coming years if nothing is done to protect them.
Commercial whaling is a significant threat to some whale populations as some species, such as the North Atlantic right whales, sperm whales, minke whales, and blue whales, are explicitly targeted by whalers.
Even in places where species are not targeted, or whaling is prohibited, whales are still affected by commercial fishing activities such as ship strikes and entanglement in nets.
Up to 80% of North Atlantic right whales have been caught in fishing nets at some point, and some may even get caught multiple times in their lifetime.
Climate change also poses a threat to whale populations.
Unique Adaptations and Survival Strategies:
Whales have a thick layer of fat (blubber) beneath their skin.
Blubber provides insulation, which is particularly important for species that live in regions with cold water.
Whales are warm-blooded, and they need insulation to maintain their metabolism in the frigid water where they live.
The layer of fat may also serve as a store of energy, especially for species that migrate for long periods without eating, such as the humpback whales.
Whales also use blubber to maintain buoyancy so they can swim and dive efficiently.
Another significant adaptation demonstrated by the cetaceans is their advanced communication.
Some species, like sperm whales, emit high-frequency clicks, which can be used to locate prey, navigate, or communicate with other whales.
Humpback whales also produce melodic sounds known as whale songs, which they use for communication.
Cultural Significance and Human Interactions
As large majestic creatures, many indigenous people, especially those who live in close proximity to whales, have a profound respect for them.
In some cultures, these whales are regarded as sacred beings and are often included in myths and folklore.
In fact, whales are so respected in some coastal cultures that they would hold funerals for beached whales.
In some other places, whales were actively hunted and exploited for their meat, baleen, blubber, and other body parts.
Whaling has existed since the Stone Age and has continued into modern times.
In 1853, whales in the United States made up to US$11,000,000 (£6.5m) in profit.
That’s equivalent to US$348,000,000 (£230m) at modern rates.
Today, whaling is heavily regulated in many countries to protect endangered whale species.
Future Prospects and Research
Whale communication and social interactions present a potentially fascinating study area for scientists.
Current studies suggest that whale songs are not just random noises.
They are complex and structured vocalizations.
Whales in different regions may even produce different songs, which suggests that they might have even more fascinating significance than initially thought.
Experts are also looking into the intelligence and cognitive abilities of whales to understand how they learn, communicate, and even solve problems.
Scientists are still interested in learning more about how these mammals transitioned from land to water.
Although a lot has been uncovered in recent years, whale evolution still has some gray areas that are yet to be resolved.
Whales are arguably the most fascinating group of marine animals.
This broad group consists of several species of mammals that live in diverse habitats and exhibit a wide range of behavior.
Whales are broadly classified into baleen and toothed whales based on their feeding adaptations.
These apex predators contribute to the balance of organisms within their ecosystem while aiding the supply and distribution of nutrients.
There’s still much to learn about whales, and future research may reveal even more fascinating facts about these majestic marine mammals.