Key takeaways
- The largest member of the dolphin family, not a whale in the everyday sense.
- This population is built around herring. Other populations eat entirely different things.
- Fin shape and saddle patch identify a particular animal for life.
- They come to these fjords in winter and leave when the fish does.
The largest dolphin in the ocean
An orca is a dolphin. Not a whale that resembles a dolphin, not a close relative of one: a full member of the family Delphinidae, and the largest animal in it by a wide margin. Everything you know about dolphins applies here, scaled up and made considerably more serious.
A mature male reaches roughly nine metres and weighs several tonnes. His dorsal fin is the giveaway, a tall straight blade that can stand close to two metres out of the water and is visible across a fjord on a calm day. Females are smaller, six to eight metres, with a shorter fin that curves back rather than standing upright.
The black-and-white pattern is not decoration. The white eye patch, the white underside and the grey saddle behind the fin break up the outline of a very large animal in open water, and the flash of a white belly is used deliberately during a hunt to move fish where the pod wants them.
One species, many separate peoples
The most important thing to understand about orcas is that the word describes a species and almost nothing else. Around the world there are populations that specialise in fish, populations that specialise in seals and other marine mammals, and populations that specialise in sharks. They share the ocean and they do not mix.
These groups differ in size, in markings, in the sounds they make, in how they hunt, and in what they will and will not eat. They do not interbreed even where their ranges overlap. Biologists describe them as ecotypes, and they behave far more like distinct cultures than like regional variations.
The animals off northern Norway belong to a fish-eating population. Their entire annual cycle is organised around finding and eating herring, and a seal swimming past a hunting pod is in no particular danger from them. That is a fact about this population, not about orcas in general.
A dorsal fin clear of the water, the one reliable identifier
How many, and where they go
Nobody counts them exactly, because they are mobile animals in a very large ocean. Estimates for the north-east Atlantic as a whole run into the tens of thousands, with a substantial share using Norwegian waters at some point in the year.
What matters more for a visitor is that these fjords are not their home. They are a winter feeding ground. The whales arrive when the herring arrives, spend the dark months working the shoals, and disperse when the fish leaves to spawn.
Where they spend the rest of the year is less well documented, which is honest rather than evasive. Some are recorded far offshore, some along the coast, some in waters well to the north. The winter fjord aggregation is simply the time and place where they are easiest to find, which is why the entire industry exists in the season it does.
The honest summary is that the winter is known in detail and the rest of the year is known in outline.
Every animal has a name, or at least a number
Orcas are unusually easy to identify as individuals, and researchers here take full advantage of it. The shape of the dorsal fin, the nicks and notches cut into its trailing edge over a lifetime, and the exact pattern of the grey saddle patch behind it are as good as a fingerprint.
Photographs taken from boats are compared against a catalogue, and an animal seen this winter can be matched to one photographed years earlier. Over time that builds something far more useful than a headcount: a record of who travels with whom, which is how the family structure of this population became known at all.
Whale-watching boats contribute to this. A clear side-on photograph of a fin with the saddle patch visible is genuinely useful data, which is a pleasant thing to know while you are standing on a cold deck with a camera.
Two metres
The dorsal fin of a mature male orca can stand close to two metres out of the water, taller than the person watching it.
A long life, and a slow one
Orcas live on a human timescale. Females commonly reach fifty and can go considerably further, into their seventies and beyond in well-studied populations. Males have shorter lives, typically thirty to fifty years, and the difference is consistent enough that it is treated as a feature of the species rather than bad luck.
They breed slowly to match. A female has her first calf in her teens and produces one every few years at most, with a pregnancy lasting around a year and a half. A pod does not recover quickly from losing an animal.
Females also stop breeding long before they stop living, which is rare enough among mammals to be worth stating plainly. An older female may spend decades not reproducing at all, and what she does with those decades turns out to be central to how orca society works.
All of which makes an orca population a slow thing to change in either direction. A good run of herring years does not produce a boom, and a bad decade does not empty the coast overnight. The animals working these fjords this winter are, in most cases, animals that were working them a decade ago, and several of them will still be here a decade from now.
