Since their land-dwelling ancestors  returned to the sea some 50 million years ago, whales have proliferated into a wide variety of sizes and specializations.  Cetacea, the order to which they belong, has 14 distinct families still surviving today.  Being mammals, they share the defining traits of that class.  They are warm-blooded, have live births, nourish their young with milk, and breathe air (though for them, every breath is a conscious choice, rather than the reflexive action it is for us).  All are entirely aquatic.  Cetaceans carry out all of their life functions in the water, a condition unique among mammals, with the exceptions of Sirenians (the order to which dugongs and manatees belong). 

So who are we talking about when we say whales and dolphins?  Let’s meet some of them. 

Perhaps the most fundamental distinction is that of baleen vs. teeth, which determines which of two suborders the species belongs to.  Whales in the Mysticeti suborder have baleen plates that serve as a filter-feeding system, while those in the Odontoceti suborder have teeth.  Baleen is essentially plates of keratin – a material also found in your hair and fingernails – that grow from the whale’s upper jaw.  It allows the animal to take in large amounts of water and to filter it out while retaining the krill, plankton and other small organisms it feeds on.

Baleen whales are generally larger.  This group includes the blue whale, generally believed to be the largest animal ever to have lived on our planet.  Toothed whales have a much greater variation in terms of size and weight.  The sperm whale is the largest, weighing in at a little better than a third of the blue’s gargantuan proportions.  The smallest are porpoises like the Vaquita, which are only four to five feet in length. 

Toothed whales are equipped to pursue larger prey animals like fish, molluscs and a wide variety of other invertebrates.  Most species use echolocation to navigate and  hunt.  No baleen whales are known to have this ability.

Toothed whales are by far the more diverse group.  Among them are the oceanic dolphins, belugas, porpoises, sperm whales, river dolphins and beaked whales.

What’s the difference between a whale and a dolphin?

Essentially, there isn’t one.  Not in a strict, technical sense.  Though the use of the term whale generally refers to larger varieties of cetaceans, dolphins are really just a particular type of smaller whale.  To take an example, killer whales (orcas) are actually the largest species of the dolphin family.  So with them it isn’t really either or. 

What’s the difference between a dolphin and a porpoise?  

Though the terms are sometimes mistakenly used interchangeably, there are a number of notable differences. The most obvious has to do with appearance.  Dolphins generally have longer and more pointed snouts, more curved dorsal fins, and longer, leaner bodies.  Porpoises’ dorsal fins are more triangular, the face rounder, the body more stout.  They also have flatter, spade-shaped teeth, as opposed to those of dolphins, which are more cone-shaped.  

There are also interesting behavioral differences.  Dolphins are very ‘talkative’, and use a range of sounds that are audible to humans.  Porpoises communicate at a higher frequency than we can hear, and it’s believed that they are much less chatty than their dolphin cousins.  They also travel in smaller groups and tend to keep a lower profile to avoid predators, unlike dolphins who are more likely to go with large group size, speed and less subdued surface behavior for protection.

The Delphinidae (oceanic dolphins) and Phocoenidae (porpoises) families are both varieties of toothed whales.  Dolphins are the largest family of cetaceans by number of species.  Members include:  orcas, false killer whales, pilot whales (both long and short-finned varieties) and melon-headed whales.  All technically dolphins.   The porpoise family has 7 species, among them the Harbour Porpoise, Dall’s Porpoise, and the Vaquita.

Don’t some dolphins live in freshwater?

Yes, a number of dolphin species live in river systems in warmer regions of the world.  Most are quite distinct from oceanic dolphins, and make up different families.  A few are more closely related, with their ancestors having entered freshwater systems more recently.  

River dolphins evolved to survive in warm, relatively shallow water.  Since their habitats are generally murky, they rely on echolocation and keen hearing to detect prey, which is caught using their long beaks and conical-shaped teeth.  Unlike other cetaceans, they have little to no blubber.  

Since they are restricted to certain tropical rivers or deltas, as opposed to more widely distributed oceanic dolphins, river dolphins are extremely vulnerable to habitat degradation.  One species, the Baji (or Yangtze River Dolphin), is already considered to be functionally extinct.  Others facing similar pressure are the Boto, which lives in the Amazon, and the South Asian River Dolphins of the Indus and Ganges river systems.

Among those species more closely related to oceanic dolphins are those that have the ability to live in both salt and freshwater habitats.  Among these is the Irrawaddy dolphin of the Mekong and Irrawaddy Rivers.  Others, like the Tucuxi, have adapted to  live only in the freshwater of the Amazon, and likely wouldn’t do well in an ocean environment.  Then there are a few oceanic dolphin populations known to live much of their lives in river and estuarine systems, with an example being the Indo-Pacific bottlenose dolphins in the Swan River system of Australia.

What are sperm whales?

Sperm whales, and their two smaller cousins – pygmy and dwarf sperm whales – derive their name from a waxy, semi-liquid often present in the whale’s head.  The term is a truncation of ‘spermaceti whale’, as the substance was originally identified as semen, quite inaccurately.  So called sperm oil made these species high value targets of the whaling industry as it could be used for oil in lamps, lubrication, and as a fixative for perfumes.  

This whale, so prized in the 19^th century, is not only the largest toothed whale, but the largest toothed predator on the planet, making it the perfect antagonist for the novel Moby-Dick.  Recent research of whaling records from this period have revealed a remarkable intelligence and adaptability as these whales learned to modify their behavior so as to evade the whalers of the time.  

What is a beaked whale?

With at least 24 species, Ziphiidae (beaked whales) in the second largest family of toothed whales.  Marine science recognizes them as one of the least known groups of mammals – certainly least known among cetaceans.   This is in part because they are relatively less abundant, but also because of the deep-sea habitat they prefer.  Only a few are better known, and only because they were of commercial interest to hunters .  Among them are  Cuviers’ and Baird’s beaked whales.  

The key distinguishing feature of this family is the presence of a snout, or ‘beak’, not unlike those of many dolphin species.  Beaked whales are moderate in size as whales go, with the larger species getting up to about 13 metres.  Many are sexually dimorphic, meaning that one or the other gender is much larger than the other.  A unique characteristic of the group is that virtually all of the whales’ blubber is wax ester.

The main thing to know about beaked whales is really how little we know.  If we’re to ensure their protection we’ll need to understand much more about their group composition, their migratory patterns, and their feeding behaviors.

What’s in a name?  

You may have noticed how many of the names we’ve given to cetaceans to identify their particular species are so often based on some or other given trait possessed by that whale.  Often a very superficial one.  Presumably we learned to distinguish one fom another as we pursued them in the whaling industry.  Humpbacks, blues, bowheads.  The right whale got its name because it swam more slowly than other large whales, and it would it would float after being killed – thus it was the “right” whale to hunt.  

Names assigned by people who saw a commercial potential in a commodity produced by the ocean.  They perhaps weren’t in a great position to know what they were truly dealing with – fascinating, highly-intelligent creatures with their own languages and cultures.   Today, with everything we’ve learned about them, we know better.

Perhaps we owe it to these remarkable animals to at some point reconsider some of our naming conventions.  To give them names which are more dignified and worthy of what they really are.  Consider, for example, the cetacean species likely the most widely recognized around the world because of its desirability in marine theme parks and aquaria.  A ‘bottlenose’ is a superficial feature to distinguish a being of this nature – arguably the other most intelligent race on the planet along with ourselves.  Surely there’s something more substantial than the shape of their noses to define them?

For The Orca’s Voice, 

Dakota, Canadian Cetacean Alliance