Silent Killers vs Chatterboxes: Differences in Transient and Resident Killer Whale Communication
There are two subspecies of killer whales that inhabit the eastern North Pacific: transient killer whales and resident killer whales. These two subspecies have not interbred for at least 250,000 years and display drastic differences in social structure, behavior, prey preference, morphology, and, interestingly, communication styles.
Transient killer whales feed exclusively on other marine mammals, such as seals, porpoises, sea lions, and even the occasional large whale. These marine mammals have excellent underwater hearing and are able to detect transient killer whale calls from several kilometers away and display anti-predator behavior when exposed to these calls. Therefore, “eavesdropping” by potential prey is an issue for transient killer whales, and it has shaped their vocal behavior. Transient killer whales are almost entirely silent as they go about their day. They only become vocal in two instances: after they have made a kill, and when they are participating in surface-active, social behaviors.
Resident killer whales, on the other hand, only feed on fish. Salmonids, their preferred prey species, have very poor hearing at the frequencies in which killer whales communicate. Therefore, resident killer whales are often loud, chatty, and can be generous in their use of echolocation calls.
There are three types of vocalizations used by killer whales: clicks, whistles, and pulsed calls. Clicks are used during echolocation and help whales orient themselves and locate prey. Whistles are used for socialization and in short-range communication. Pulsed calls are the most common form of killer whale vocalizations; they are used in group recognition and coordination of behavior. These calls are used by biologists to distinguish individual groups of whales.
During studies of resident and transient communication, researchers find that residents produce pulsed calls at a higher rate than transients. One study, published in 2005, showed that transients produce no vocalizations whatsoever apart from when they have made a kill or are participating in surface-active behaviors. What is the reasoning behind food-associated vocalizations? While we still are not sure, it is likely related to socialization. Transients frequently share prey amongst each other and high rates of vocalization after a kill may aid in doing so.
Photo: Eva Saulitis (left) and NOAA Fisheries (right)
Deeke V., Ford JKB., and Slater P. 2005. The vocal behaviour of mammal-eating killer whales:
communicating with costly calls. Animal Behavior, 69: 395-405.
I was so thrilled to spot a few members of this resident pod flitting around the bay this afternoon (6/18/18). They were spread out, likely searching for salmon along the shoreline. AP pod was seen extensively last summer, but hadn’t been seen for many years prior. They are truly a mysterious pod!
Here is adult male AP9 making a few close passes by our vessel, the M/V Discovery.
An unknown male resident killer whale meandering out of Kachemak Bay last summer.
This was an interesting encounter; the only whales in sight were two unknown adult males, an unknown juvenile, and, curiously, AX36 and her newest calf. No other members of AX27 were pod present, nor were AX36’s other two daughters.
The next day, we found these two males again, as well as the rest of their uncatalogued pod. This time, all of the AX36 matriline was present with them.
We still don’t know who the unknown pod is. I’ve spent months looking through catalogs and haven’t found them. At this point I suspect they truly aren’t catalogued at all. Hopefully they show up again at some point so we can ascertain if they belong to the southern Alaska resident population or the unnamed population in western Alaska.
Fascinating interaction with the Bigg’s (Transient) Killer Whales marking the first confirmed case of Infanticide in Killer Whales. See our Facebook page for more.
#Repost @gary_j27 with @get_repost
Get ready to have your minds blown! Last winter, while doing some research up near Alert Bay, we had an encounter that changed everything about the way we understand killer whales. We witnessed the first documented case of infanticide among killer whales. Furthermore, it was the first documented case of mother assisted infanticide recorded in any mammal species other than humans. T068 (a post reproductive female) and her son T068A attacked and killed a brand new calf in the T046B matriline, T046B5. The fight that ensued between the twp groups was astonishing. T046B (the mother of the calf) ramming into the male, T068A. Other members of the T046B matriline were also fighting to try and get the calf back. The vocals were absolutely insane including calls that haven’t been heard before. In the end, the T068s took the dead calf with them and were still pulling it around when we had to leave due to light. Here are some of the photos from that day. If you’re more interested in what happened and why this may have happened, I am posting the link to the paper that was published today. It’s a great paper and I’m so humbled to be a part of it. Thanks to Jared Towers and Muriel Halle who I shared this experience with. The link is in my profile.
#killerwhale #orca #oceanecoventures #whale #whalewatching #oh_canada_ #whale #whalewatching #wildlife #wildlifephotography #nikon #nikontop #nofishnoblackfish #saveoursalmon #canada #hellobc #sharecangeo #pacificnorthwest #pnw #biggsorca #beautiful #bc #beautifulbritishcolumbia #blackfish #blackfisheffect #infanticide #science #nomorefishfarms
Everything we thought we knew about killer whales has been shaken up.
Today, the article “Infanticide in a mammal-eating killer whale population” by Towers et al. was published in the journal Nature. It documents the very first case of infanticide (the killing of an infant) in killer whales. It is also the first case of a mother-assisted infanticide in a species other than humans.
Up until now, aggressive interactions between killer whales (in the wild, at least) were virtually unheard of. Just the other day I was pondering the lack of violence in killer whale society. But just as killer whales tend to do, they upturned everything we thought we knew about them.
The attack involved the T068s and T046Bs, two families of West Coast Transient killer whales.
Post-reproductive female T068 and her son, T068A, attacked mother T046B and her offspring. A previously undocumented neonate, dubbed T046B5, was present, and it became clear that this calf was the target of the attack.
Figure caption from the article: “Observations leading to infanticide. (A) Fresh wounds on left flank and kinked spine anterior to dorsal fin on T046B4. (B) T046B with offspring T046B2 and (neonate) T046B5. (C) T068A surrounded by T046B, T046B1 and T046B1A. (D) T046B ramming T068A from below sending spray and blood into the air.”
T046B attempted to protect her calf by ramming the male T068A. Other members of the T046B family also appeared to try and get the calf back. At one point, T068A had grabbed the neonate by the flukes and likely had drowned it. He paraded the calf’s carcass around in his mouth. Both he and his mother took turns carrying the calf around while the T046Bs trailed behind them. The researchers recording this attack were also using a hydrophone to listen to the whales’ calls, and they documented highly erratic vocalizations that have never been heard before.
Figure caption from the article: “Observations following infanticide. (A) T068A with the fluke of T046B5 in the left side of his mouth. Fresh scars from the teeth of another whale can be seen on his left flank and rostrum. (B) T068 surfacing with the fluke of T046B5 visible in the left side of her mouth. (C) T068A surfacing with the dorsal fin of T046B5 visible off the left side of his melon. (D) T068 rostrum to rostrum with T046B5 approximately 215 minutes after its death.”
Eventually, the light was dim and researchers had to leave the group.
This leaves us all wondering: what is going on? Why did the T068s kill a neonate calf? In other species, infanticide is fairly common as the killing of an infant often brings the mother back into estrus and males can mate with her. It’s likely this is what was going on as other explanations, such as competition for resources, do not adequately explain it.
This is a major discovery in killer whale behavior and I have no doubt we’ll learn more as the years go by.
Culture can be defined as information or behavior in a group that is obtained from conspecifics through social learning. Human culture has been studied extensively, but biologists are starting to examine cultures in other animals, and killer whales are one of them.
Killer whales can be found in every ocean on the planet. Apart from us, they are the most widespread mammal on earth. They live in matriarchal societies and generally have strong maternal philopatry (basically, they stick close to mom for most of their life). While currently only one species of killer whale is recognized, there are at minimum 10 different kinds of killer whales around the world, called ecotypes. Each of these ecotypes differs in morphology, diet, vocalizations, genetics, and behavior. They are fairly xenophobic, meaning the ecotypes do not associate with one another and don’t intermix.
Each ecotype also has its own unique culture, mainly in the form of diet and hunting techniques. For example, large type B killer whales––also called pack ice killer whales––specialize in hunting seals through a hunting method called wave washing:
This is a learned behavior and has to be taught to calves in order for them to master it.
Another example comes from resident and transient killer whales. Resident killer whales feed solely on fish, mainly salmon, while transient killer whales prefer marine mammals such as seals, sea lions, and other cetaceans. This, again, is a cultural preference.
Dialects are another important factor in killer whale culture. Each population and pod has its own unique vocalizations. Killer whales are vocal learners and learn these dialects from family members, thus making this culture. It is thought that killer whales prevent inbreeding by mating with individuals whose dialects are different from their own. However, they also seem to avoid mating with whales whose dialects are too different, thus preventing mating between ecotypes.
Cross-ecotype dispersal has also never been observed. This is probably because it would be far too difficult for a killer whale of one ecotype to migrate to another. A killer whale that’s been raised to eat salmon and hunt salmon would have a hard time learning how to hunt marine mammals and consume marine mammals.
How might these cultures be impacting how killer whale ecotypes are evolving?
This is still a fairly new field of research, so not much is known quite yet. However, we do have some ideas of how these cultures might be affecting killer whales on a genetic level. Let’s take a look at residents and transients again.
Studies on killer whale genomes have shown that there is some sort of evolutionary pressure occurring on some genes related to diet in residents and transients. Biologists have found that genes involved in the early development of the digestive tract differ in residents and transients, as well as genes that are involved in the hydrolysis of long chain fatty acid esters. Additionally, biologists have found differences amongst the two ecotypes in the genes involved in the methionine cycle. Methionine is an essential amino acid that the body cannot produce on its own, and it must be obtained from the diet via protein intake. They have hypothesized that transient killer whales are consuming large amounts of mammal protein in a sporadic manner, while residents are eating smaller amounts of fish protein in more consistent intervals, and thus, these differences could be exerting different selection pressures (namely, cultural preferences for food) on these genes. It’s also been noted that transient killer whales have more robust jaws and differently shaped skulls.
Another gene that is different between killer whale ecotypes is the FAM83H gene. This gene is involved with keratin cytoskeletons in epithelial cells. The gene is different in the ecotypes found in Antarctica compared to those found in the North Pacific. Antarctic killer whales, particularly type B and type C, usually have a layer of yellowish algae called diatoms found on the surface of their skin:
Photo: NOAA Fisheries Service
In order for killer whales to shed their outer layer of dead skin and grow new ones, they need to have ample blood supply to those cells, Antarctic killer whales, however, live in an extremely cold environment and likely direct blood flow to more vital parts of their body to keep warm, so skin regeneration is likely slow. This allows for the build-up of diatoms to occur. It’s been discovered that type B killer whales make long migrations to the warm waters off of Uruguay and Brazil, likely to aid in the sloughing of old, diatom-infested skin. When they return to Antarctica, those previously yellow spots are now a shiny white color again. Culture doesn’t have a clear role in this gene, but it is certainly worth investigating further as culture does have geographical implications at times.
There are also other morphological differences between killer whales that could be caused by culture, though scientists have not yet identified candidate genes. Here is a part of a table from Hal Whitehead’s paper “Genome-culture coevolution in whales and dolphins”:
Culture and its role in evolution is an exciting and new field of research. Knowing that culture can have an impact on organisms at a genetic level adds a whole level of complexity to evolutionary biology, but it can explain some of these fascinating and profound differences amongst killer whale ecotypes.
Normally I don’t stray much into the captivity debate, but this article is full of so much misinformation I just can’t let it go. I am not a SeaWorld fan and in general I am against keeping cetaceans in captivity (with a few exceptions) but this is just too much for me to pass over.
1. “Intentions became questionable, however, with the events that followed: staff from major aquariums began showing up, under the pretense of saving Tyonek’s life. As we pointed out late last year, among these allegedly concerned individuals was SeaWorld’s marine mammal curator.”
There is not some grand conspiracy to “imprison” whales and dolphins the moment they strand on a beach. Young calves are usually non-releasable for a multitude of reasons (and anybody with a background in marine mammalogy knows this!). Additionally, it’s pretty standard for staff from other aquariums to assist in large and rare rescues. Staff from aquariums that have captive belugas went to the SeaLife Center after Tyonek’s rescue because beluga rescues are rare and the staff at ASLC may not necessarily have had the knowledge required to care for a newborn beluga. ASLC does not keep cetaceans and the only cetaceans that have ever been held there prior to Tyonek were a rescued harbor porpoise and an unnamed rescued beluga, both of which died soon after rescue.
2. Things went further downhill when the Alaska Sealife Center began to publicly display – to exploit – this baby whale before a decision was reached as to whether he would be able to be released. Publicly displaying Tyonek likely decreased his chances for survival in the wild, thanks to increased exposure to humans.
This paragraph tells me the author has never been to the Alaska SeaLife Center and likely doesn’t know what it looks like. Initially, Tyonek was kept in the I.Sea.U, the marine mammal equivalent to an intensive care unit. He was not viewable to the public during his initial rehabilitation efforts. As he gained strength and got a little bigger, they moved him to an outdoor pool, which was larger, deeper, and the outside air temperature better resembled what he would naturally be living in. Here is a photo of that pool (modified slightly to accommodate Tyonek):
I have been here many times myself and believe me when I say it’s virtually impossible to attract the attention of any animal in those pools. You are high up and out of their line of sight. You are a passive, unobtrusive observer. The likelihood of Tyonek even being aware of guests looking at him is essentially zero and would have no effect on his ability to be released. Regardless, he was having lots of human contact and exposure to humans with his caretakers; this close contact was necessary for him to even survive, and this is in part one reason why cetacean calves are usually unreleasable to begin with.
3) As the Whale Sanctuary Project pointed out, there should have been asanctuary option for Tyonek, not just SeaWorld’s exploitative tanks…Unfortunately, NOAA and SeaWorld did not give qualified organizations, or the public, a say in their decision.
While I think sanctuaries are something that should be studied in depth and explored, THERE ARE NONE! They do not exist. It is not an option right now because none exist. Additionally, NOAA often allows public input on all sorts of projects (and that’s great!) but the fact is half the people who yell on the internet about captive cetaceans don’t know much about marine mammal biology or ecology. Allowing public input on whether a baby whale should be released or not would probably lead to a lot of dead baby whales.
Rant over, back to your regularly scheduled marine mammal photos and memes!
What is it about killer whales that captivates us so much?
I’ve spent several years now as a naturalist on a whale watching boat. We typically see humpback whales, harbor porpoises, sea otters, harbor seals, and various species of seabirds on our trips. People love these animals and they thoroughly enjoy watching them in their natural habitat and learning about their life histories.
But whenever our captains announce on the loudspeaker that killer whales have been spotted, the entire energy of the boat changes. Folks who spent most of the afternoon watching the wildlife from inside the cabin are suddenly up on their feet jostling to get the best position on deck. Photographers frantically swap lenses as quick as they can. There’s always a strange hush as the passengers anxiously await the arrival of the killer whales. Even in the roughest, nastiest weather, people will abandon the warmth and comfort of the cabin to catch a glimpse of these animals.
It’s hard to explain what exactly it is about killer whales that causes such a marked change in behavior in people. I’ve dedicated my whole life to killer whales and even I still have a hard time answering the question “Why do you like them so much?” As a scientist, I can tell you the aspects about their biology that fascinate me, but there is another level of love and adoration deep in my heart that I can’t explain.
Maybe it’s the power and grace they convey when they slice through the water. Maybe it’s the fact they are the world’s most accomplished predator and yet still retain a gentle, inquisitive nature. Maybe it’s their remarkably strong social bonds and reliance upon family for survival.
Whatever it is, it captures our attention and emotions in a way no other animal can.