A student's journey through the world of bioacoustics


Bigg’s, Transients, Residents, Offshores…What are all these whales and how are they different?

It’s our final week on Saturna Island for the summer. The resident orcas have been spending more and more time out in the open Pacific, and so we haven’t seen them for a week. It’s the longest we’ve gone without seeing them since we arrived! We have, however, seen Bigg’s orcas a few times, and we’ve heard them too! Which brings me to the subject matter of today’s post: What do I mean when I say Bigg’s, Transient or Resident orca? How are they different, and how can I tell them apart?

Let’s start with the very basic. Orcas are the largest species of dolphins, but scientists are not so sure anymore that they are, in fact, just one species. There are many different kinds of orcas, all of which have their own unique cultures, dialects, prey preferences, behaviours and looks. It’s thought that some of these may be different species altogether.

In British Columbia, we have 3 different kinds of orcas: residents, Bigg’s, and offshores. Offshores, like the name suggests, live away from the shore. They’re not seen very frequently, and little is known about them, so I won’t give them too much focus here. We see the residents and the Bigg’s orcas pretty frequently though. 

My area of focus has been the resident orcas. British Columbia is home to two different populations of resident orcas – the Northern and Southern residents. Their geographic divide is, approximately, somewhere around Campbell River. They are fish specialists, eating a diet that is 97% salmon, and, more specifically, 78% Chinook salmon. They are extremely social, and the Southern Residents in particular can be quite boisterous. They are usually seen in large family groups, frequently vocalizing and performing all kinds of exciting surface behaviours.

On the other hand, the Bigg’s orcas, previously known as transients, eat marine mammals. Individual Bigg’s orcas may be marine mammal generalists, eating seals, sea lions, porpoises, and baleen whales, or they may specialize in particular types of marine mammals. Their group size typically ranges from 1 to 9 individuals, with about 4 or 5 being ideal. They need to keep their groups small and their behaviour stealthy, because the prey they hunt are smart, have good eyesight, and can hear the frequency range orcas vocalize in very well. They surface less frequently than residents, and change direction often. Sometimes, they even surface low to the water, in the troughs of waves, or at odd angles, presumably to disguise their towering dorsal fins from prey who may be watching for them above the surface. Bigg’s orcas rarely vocalize or engage in surface behaviours, except for during or after a hunt. 

So behaviourally, these two groups of orcas are quite different. Their group sizes, movement patterns, and frequency of surface and vocal behaviour differ dramatically. But what about how they look?

Resident and Bigg’s orcas do look different, though perhaps not to the casual observer. Looking at orcas is much like looking at any animal species or breed for the first time – if you’ve only seen them a few times, they all look the same. But, if you do a little bit of practice, or spend a lot of time with them, you start to notice all of the subtle differences between them, and they begin to look very different. Here are the differences you should watch out for: 

Bigg’s orcas are physically larger than resident orcas. Their dorsal fins and saddle patches, the characteristics used to identify individual orcas of all kinds, also differ from residents. The dorsal fins of resident orcas are often rounded at the top, and quite shapely. Many female residents have dorsal fins that tip backwards at the top, and most male residents have dorsal fins that appear fairly straight, or even swept forward. Bigg’s orcas typically have much more broad, triangular and pointed dorsal fins than resident orcas. The dorsal fins of some female Bigg’s look quite a lot like sharks. 

Male resident and male Bigg's orca

Male resident and male Bigg’s orcas

Female resident and female Bigg's orcas

Female resident and female Bigg’s orcas

Many resident orcas have what’s called an “open saddle”, which is to say, a grey saddle patch with a black finger or intrusion, while Bigg’s orcas only have solid grey, “closed”, saddle patches.

A Southern Resident with a particularly unique open saddle. L72-Racer.

L72-Racer – a Southern Resident with a particularly unique open saddle.

Lastly, Bigg’s orcas typically have more extensive scarring than residents, likely due to the hazards of hunting large marine mammals with sharp teeth. Here’s a couple photos of resident and Bigg’s orcas. See if you can spot the differences! 

A group of resident orcas.

A group of resident orcas.


A group of Bigg`s orcas.

Now that you know how to tell the difference, you might be wondering, why would you need to? Well, for one thing, it makes it much easier to interpret the groupings of orcas that you see in the Salish Sea. Bigg’s orcas are very rarely seen in even remotely close proximity to the residents. They simply don’t interact with one another. So if you see a large group of resident orcas, followed shortly after by a smaller group of orcas, that smaller group is probably also resident orcas.

Another reason that it may be useful to know this is to know when you could and could not easily pursue legal (or other) action against boats that are misbehaving around the whales. In Canada, boats are supposed to stay 100m away from the orcas, and travel along beside orcas, rather than in front or behind. When it comes to the resident orcas, this is law, and is punishable with fines, and even loss of license to conduct whale watching tours. This is important for the resident orcas, because their population is very small. This population has numbered only about 80 orcas over the past few years, and are listed as endangered. While there are orcas all over the world, the number of orcas in each population is very important, because they don’t interbreed with other populations, and carry out their own unique cultures and roles in the ecology of their area. Our Southern Residents aren’t doing very well. 

The Bigg’s orcas, however, are doing alright. They’re considered “threatened”, which, when listing species at risk, is the second least concerning listing. Ultimately, they could be doing better, but they seem to be doing alright, and their population is not in any immediate danger of extinction. Because they socialize only within their own community, have different culture and dietary preferences, and ultimately occupy a different ecological niche from that of the Southern Residents, the survival of the Bigg’s orcas is not tied to the survival of the Southern Residents, and so it makes sense from a government standpoint to legislate behaviour around the Southern Residents more strictly than behaviour around the Bigg’s orcas. This means that Bigg’s orcas do not, at this time, have any special laws applied to them, and boating around Bigg’s orcas is the same as boating around seals, sea lions, porpoises and humpback whales, legally speaking. It’s still recommended that you stay 100m away and flank the whales rather than chase them or cut them off, but it’s not a legal requirement. A case could be made against boats that are closer than this to a marine mammal under a Canadian law which states that it is illegal to disturb a marine mammal, but to win such a case you would need both proof that the boat was too close to the whales, as well as proof that the boat disturbed the whales. The law is a tricky business. 

There is one final way to tell these two types of orcas apart, which I held out on telling you about until now. As a student of acoustics, I may be somewhat biased when I say that I think the coolest difference between these two groups is that they actually sound different, so much so that i don’t even need to have heard the calls they’re making before to know which group I’m listening to. I do find it helpful to make associations with more familiar sounds when I listen – I listen for high pitched squeaks, squeals and honks when hearing residents, and sad or whining cats when I hear Bigg’s. I’ve included an example of each below from recordings from the SIMRES hydrophone array – have a listen and decide for yourselves what you think they sound like!

A short selection from J and K pods passing through Boundary Pass in the night.

Bigg’s orcas celebrating a successful hunt in Boundary Pass.

Photos by Kristen Kanes


Superpod take two!

Yesterday was a big day for us on Saturna Island. Paul Cottrell of DFO, Tom Dakin of Ocean Networks Canada (my boss), and myself all gave presentations about underwater sound, hydrophones, the SIMRES hydrophone array and our own research. We were all hoping for a bonus show from the orcas, who had been reported going South near Vancouver earlier that day, but no luck!

They’ve been in this pattern lately where they go North to the Fraser River sometime after the late morning, and go back South to San Juan Island in the morning or early afternoon the following day. (These two locations are important fishing areas for the Southern Resident orcas in the summertime.) Given that we hadn’t seen them by 6 pm, we assumed they just weren’t coming. But boy were we wrong!

We were just packing up to go see some friends at a potluck dinner when our host looked out the window, pointed, and said, “There’s a whale!” Shocked, Lily and I ran back outside with the research gear. We were half convinced that there wasn’t a whale, and mostly convinced that, if there was a whale, it must be a Bigg’s whale (which we’re not researching). We set up everything in record time, took a good look at the first whale coming through, and lo and behold, it was J whale! J Pod and K Pod had returned for superpod round two!

It was a magnificent viewing. They came super close to the land, and they were breaching and tail lobbing and slapping their pectoral fins on the surface. We saw one whale spyhop really high out of the water, and we could hear it producing echolocation clicks while it was up! For those of you who don’t know, it sounds like this:

This was pretty amazing, and a very unique experience. The air-water interface is very reflective, acoustically speaking. Sounds produced under water generally reflect back into the water when they hit the surface, never to be heard in air. So hearing an orca from above the water is a rarity. A wild orca producing sound above the water’s surface is also extremely rare! This was the first and only time I have ever heard a wild orca produce sound above the water. Absolutely incredible.

We also got some great data. We were able to get visual tracks of many individuals, and they were pretty chatty while they were here. Since we were busy collecting data during this sighting, we didn’t get much in the way of photos (except for the gem Lily took, shown below), but we did get some great acoustic recordings! So close your eyes, imagine the beautiful, deep, emerald green of the Salish Sea, and listen.



Lily's pec-slap photo

Lily’s pre-pec-slap photo

Photo by Lily Campbell


Harbour seal birth!

The whales have been away for a few days, but that doesn’t mean that we get to sleep in. Lily and I get up at 5:45 am every day to start watching for whales, just in case they surprise us (and sometimes they do).

But morning watches without whales aren’t always boring. There are often lots of other sea creatures to watch while we wait for the whales to come by. We frequently see harbour porpoises, harbour seals and river otters. There’s even a seagull that has taken to trying to land on seals’ heads when they come to the surface – a source of endless entertainment for the both of us.

But the other day, we saw something truly spectacular. The fattest seal I have ever seen awkwardly haul herself out onto the rocks for all to see. When she was on her stomach, her back fins hardly touched the ground. Of course jokes were made and laughs were had. But soon after hauling out, she rolled onto her side, and it became immediately obvious why she was so large. This seal was very pregnant, and her stomach was twitching as contractions came over her in waves. This seal was about to give birth right in front of us.

One very pregnant seal

One very pregnant seal

IMG_7345 (2)


With two DSLRs at hand and nothing more important to do, we decided to document the process and share it with you. Below is a series of photos from the event, followed by Lily’s video footage.

Warning: Some of the following photos and footage are graphic. But, given that this is a birth, you probably already knew that.

IMG_7348 (2)

Starting to push

Here comes the baby!

Here comes the baby…

IMG_7352 (2)

And a seal is born!

Mother and baby meet for the first time

Mother and baby meet for the first time

Shortly after the birth, the baby decided to explore, and got stuck in a crack in the rocks!

IMG_7398 (2)

Newborn seal stuck in a crevice

Eventually the tide washed the baby out and the two swam around the point and out of sight.

Mum and babe in the water

Mum and babe in the water

Lily’s video footage:

We were worried that the newborn wouldn’t make it because it was struggling so much to stay upright in the water and swim. But later that day, mum came back with her baby on her back. All was well, and a new life had begun!

Baby seal riding mum's back

Newborn seal riding mum’s back

Photos by Kristen Kanes, video by Lily Campbell




What am I doing here?

I thought I’d start this off by telling you a little bit about what I’m doing for the summer. I am a Master’s student at the University of Victoria. I am collecting data for my thesis, which will ask the question, “Do individual Southern Resident orcas have different “voices”?” Can we tell individuals apart by sound?

It’s an easy question to ask, but a difficult one to answer. If orcas were land animals, then I could observe a group of individuals talking to one another, and use their facial movements to infer which individual was speaking at what time. But orcas spend an estimated 95% of their time underwater. Underwater video won’t help either, because orcas don’t need to move their mouths to speak. Rather than passing air over vocal chords in their throats to make sounds, as we do, orcas pass air back and forth in air sacs in their sinus cavities. The sound is focused by the fatty tissue in an organ called their “melon,” and comes out of their foreheads.

So with no reliable visual cues to indicate who is speaking, how does one figure out who is saying what?It’s a little complicated, and does involve a few different steps, but I believe it’s doable.

The first step is the most expensive. To find out where a sound came from, you need acquire an array of underwater sound receivers, called hydrophones. You need at least 3, because, after some fancy math, each pair of hydrophones will give you one line of bearing. In other words, if we imagine a line drawn between a pair of hydrophones, we can calculate the angle at which an incoming soundwave crossed that line, giving us a line from the receivers out to infinity upon which the sound source must be. With three receivers, we can calculate up to three lines of bearing, which intersect at the location that a sound came from. This age-old method is called triangulation, or localization.

So for this first and crucial step, I will be using the array of Ocean Sonics digital hydrophones that is being deployed on Saturna Island by the Saturna Island Marine Research and Education Society (SIMRES). We have two hydrophones in the water now, and one to go. This means that I cannot triangulate the source of a sound right now, but I can draw a line on which the sound source must be. So, until the third hydrophone is deployed, I can’t localize all of the sound sources (orcas), but I can localize the leaders and trailers of a group – the whales who are far enough ahead or behind that no other whales will be in the same line of bearing at any given time. If the whale I’m focusing calls multiple times as it passes the array, then I can make a “track” of the whale’s movements to refer to after step two.

Step two is a little less passive than step one (pun intended for those of you into passive acoustics!). This step requires that I watch the whales (woohoo!). I stand on the shore near the hydrophones with my handy-dandy theodolite. This instrument is actually one used for construction and surveying, but is easily appropriate for visual data collection. It looks like a telescope suspended between two posts on a rotating base. It measures the vertical and horizontal angles of the position of the telescope. If I aim the telescope at a whale, then I can measure the vertical angle that whale is at relative to myself, and the horizontal angle it is at relative to a reference point (in this case, true North). With this information, as well as knowledge of my height above the waterline and my GPS location, I can use trigonometry to find out where the whale is. If I take these measurements on the same whale several times as it passes through the research area, then I can make a visual “track” of the whale’s movements. If this track matches the acoustic track from step one, then I can reasonably assume that the whale I was looking at is the whale that was speaking. At the same time, my assistant videos the whales so that I have a record of what happened, which individuals were there, and the movements of other whales. Since every Southern Resident orca has been photographed and is recognizable by differences in their dorsal fin shapes and saddle patches, I can use all of this information to determine which individual was making all the noise.

With a collection of calls from several individuals, I can then analyze calls of the same call type for differences after the data collection season is over. And, if I’m lucky and there are differences, then long term monitoring projects may be able to make more and better use of passive acoustic techniques to follow this at-risk population, allowing us scientists to reduce our dependence on boats for data collection and therefore our impact on the whales themselves.

So that is what I’m doing here on Saturna Island this summer. If you want to know more about the orcas, and about this community specifically, check out the Center for Whale Research at http://www.whaleresearch.com, and the Whale Museum at whalemuseum.org. Or check back here for more updates and educational blog posts!