Northern Naturalist

Marine Scientist, Naturalist, and Photographer—Specializing in Marine Mammals. Let’s Talk About Whales!

[northernnaturalist]

Hi all! My name is Emma, I am a marine scientist and naturalist from Alaska. I’ve worked primarily with killer whales and humpbacks whales here in Alaska and also in Norway. I dabble in wildlife photography and more recently, illustrations and science communication. Some examples of my work:

[northernnaturalist]

I love the diversity of Southern Ocean killer whales 🫶

[northernnaturalist]

🚨 A team of scientists, led by Phil Morin of NOAA, have published a new paper formally proposing two “new” species of killer whale: Bigg’s killer whales (Orcinus rectipinna) and resident killer whales (Orcinus ater).🚨

More than fifty years ago, researchers began studying the killer whales found off the west coast of North America. One keen-eyed scientist, Dr. Michael Bigg, noticed that there appeared to be two kinds of killer whales: a smaller, more gregarious form that fed on fish and a larger, stealthier type that fed on marine mammals. He and his colleagues dubbed the fish-eaters “resident” killer whales and the mammal-eaters “transient” killer whales (who were later renamed Bigg’s killer whales in his honor).

Two female Bigg’s killer whales in Washington (top) and a male and female resident killer whale in Alaska (bottom)

Many decades later, scientists have been hard at work trying to resolve whether or not these two forms are different species. It is not an easy task. This requires a thorough investigation into many factors, including evolutionary history, genetics, morphology, ecology, and behavior. In this paper, the researchers lay out all of the evidence and conclude that these two forms warrant elevation to species status.

As newly proposed species, both need new scientific names. There have been numerous killer whale species proposed and described in the past by other naturalists and researchers, including those in the North Pacific. Unfortunately, there are no type specimens— individual specimens upon which the first descriptions of a species are based—available for killer whales previously described from the North Pacific, so the researchers were left to examine drawings and illustrations of killer whales in the North Pacific in the late 1800s by Scammon and Cope.

The authors propose “Orcinus rectipinnus” for Bigg’s killer whales and “Orcinus ater” for resident killer whales. “Rectipinnus” presumably refers to tall dorsal fins, and “ater” means “black” or “dark” in Latin. Of note is the fact that a female killer whale from California originally examined and described by Scammon as “Orcinus rectipinnus” had seals in her stomach, suggesting she was a Bigg’s killer whale.

In addition, the authors note they are consulting with Indigenous tribes for a new common name for resident killer whales.

What’s next? In marine mammal biology, proposed taxonomic changes are reviewed by the Society for Marine Mammalogy’s taxonomy committee. If accepted, these species revisions become “official.” This has been an eagerly awaited paper by many in the field of killer whale biology and it is a great accomplishment, made possible by decades of research by scientists around the world.

A big thank you to lead author Phil Morin for letting me preview the manuscript and for answering my numerous questions in preparation for this post!

Read the paper here!

[northernnaturalist]

Hey hi I sort of forgot about this account—will try to be more active!

[northernnaturalist]

The world is full of killer whales. There exists a wonderful diversity of shapes, sizes, and coloration patterns. Some of these whales are distinguished enough to separate them into distinct ecotypes, such as the Bigg's killer whales of the North Pacific or the type C killer whales of Antarctica. Others defy such easy categorization, and instead exist somewhere along a hazy spectrum of morphological and ecological traits.

This piece displays 16 different types/forms/populations of killer whales around the world and is by no means exhaustive or representative of every killer whale; indeed, it would be difficult to fit all variations of killer whales into a single, cohesive piece.

As scientists learn more about killer whales around the world, especially those in low latitude areas, the classification of killer whales will likely change. We may see new species or subspecies come to fruition, or perhaps newly proposed ecotypes. Or, we may see current ecotype designations rescinded as research continues, as was recently done with the “type 1” and “type 2” ecotypes of the Eastern North Atlantic. Truthfully, even this piece may be an oversimplification—perhaps we should be wary of trying to box in their complex nature.

[northernnaturalist]

They’re known for being mama’s boys, but don’t let them fool you—male resident killer whales spend time with the boys, too!

Research conducted on northern resident killer whales shows that males will temporarily split from their mother’s side to form what is known as a MOSI—a male-only social interaction. These interactions may consist of a pair of males or several males together. During a MOSI, there is a lot of touching, rubbing, rolling around, and sometimes even penile displays above the surface. These groupings most often include adolescent males that are not quite grown yet and are typically composed of unrelated individuals.

You might think this may be only for competition purposes—while it’s possible some MOSIs may include some aspects of dominance-related play, it’s thought that these interactions are largely play-based and are likely important for learning social and cognitive skills. It’s also been suggested that MOSIs may be an opportunity for young males to perform sexual behaviors that they may be otherwise prevented from performing with receptive females due to social status.

While MOSIs specifically haven’t been formally described in Alaska’s resident killer whales, I have seen similar behaviors here. Here are some photos of males from AD8 and AP pod interacting!

Reference: Rose, N. A. (1992). The social dynamics of male killer whales, Orcinus orca, in Johnsytone Strait, British Columbia (Ph.D. thesis). University of California, Santa Cruz.

[northernnaturalist]

Male killer whales are never beating the mama’s boys allegations.

There’s lots of research that highlights how mother resident killer whales dote upon their adult sons, and today another paper has been published providing more evidence that supports this. As it turns out, female killer whales help protect their sons from injuries inflicted by other killer whales!

The study, out today in Current Biology, examines the density of rake marks across different resident killer whales. Rake marks are injuries caused by other killer whales; they are the result of a killer whale dragging its teeth across the skin of another. Researchers found that some males had less rake marks than others. Males that had a mother in her postreproductive years had fewer rake marks than males whose mother had died, or was still reproducing. Researchers are not yet sure how these mothers are protecting their sons, but it’s possible they help mediate their sons’ social interactions with other whales and help them avoid injury. As elder females, they likely have years of knowledge and experience interacting with different social groups. Scientists will need to examine group interactions more closely to understand the exact mechanism by which these elder mothers are helping their sons avoid injury.

But these mothers do not extend this protection to their daughters, or even their grandchildren, and it only kicks in once they have stopped having babies of their own. This makes sense from an evolutionary perspective. Sons can produce more offspring than a daughter can, so a female is wise to invest in her sons, as they spread more of her own genes around. Additionally, after a male mates with a female, he returns to his own mother, and the mother of his offspring will raise the calf her own group. This reduces the burden on his own family. Sorry gals!

Reference: Charli Grimes, Lauren J.N. Brent, Samuel Ellis, Michael N. Weiss, Daniel W. Franks, David K. Ellifrit, Darren P. Croft (2023) Postreproductive female killer whales reduce socially inflicted injuries in their male offspring. Current Biology, 33:1-7.

[northernnaturalist]

In May 2023, several whale watching operators in northeastern Japan were treated to multiple sightings of a white male killer whale.

White killer whales in Japan are rare but not unheard of—there seem to be at least 3 different individuals. Additionally, there are even more white killer whales documented in Russia!

The particular male seen in Japan in May 2023 bears a great resemblance to the famous Iceberg, a white Russian killer whale, but his saddle patches are slightly different. His pale skin is like a white canvas—every scratch and mark is easily visible, and even the algal accumulation on his skin is striking.

Nobody is sure what causes this white coloration. Russian researchers have suggested it may be albinism, but this has yet to be confirmed. Other conditions, such as leucism, can cause abnormally light coloration in animals.

[northernnaturalist]

Female killer whales are not as physically large and distinctive as their male counterparts, but they still go through developmental milestones of their own!

As calves and juveniles, female and male killer whales look virtually identical (apart from some pigmentation differences in their bellies).

Once they hit their early teens, many female killer whales are already sexually mature and capable of producing calves. In the wild, the average age of first viable birth is 15 years old but some females may start having calves as young as 11 years old (and a female in captivity once gave birth at 7.5 years old!). They will continue to have a calf on average every 5 years. There can be variation; some females may have calves every 2-3 years, and others may go as long as 14 years in between calves!

Once a female killer whale enters her late 30s and early 40s, her ability to reproduce comes to a halt, though she herself may live for another 20-30 years. This prolonged period of reproductive senescence is rare and is only seen in humans and a few toothed whale species. A grandmother killer whale will help care for her adult offspring and grandchildren and likely serves as an important source of ecological knowledge.

Reference: Olesiuk PF, Bigg MA, Ellis GM (1990) Life history and population dynamics of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. Rep Int Whal Comm Spec Issue 12:209–244

[northernnaturalist]

Killer whales are sexually dimorphic, which means males and females look different from one another. Adult male killer whales are distinguished by their exceptionally tall dorsal fins (up to 6 feet on some individuals!), their large pectoral flippers, and wide flukes that typically curl down at the edges.

With the exception of some pigment differences around the genital region, male and female killer whales look identical to one another when they are young. When males reach their early teens, they start a period of growth known colloquially as “sprouting.” This is when they start to look different from females—their dorsal fins begin to grow tall and straighten out, their pectoral flippers widen, and their flukes may start to curve downward.

Once a male reaches his late teens and early twenties, his growth slows, and he becomes physically mature.

Reference: Olesiuk PF, Bigg MA, Ellis GM (1990) Life history and population dynamics of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. Rep Int Whal Comm Spec Issue 12:209–244

[northernnaturalist]

🚨 New killer whale research alert!!🚨

Killer whale taxonomy is a big interest of mine—for the last four(!) years, I have been patiently waiting for the results of the genetic analysis of the type D killer whales sampled by scientists off Chile back in 2019.

As the most distinct and most poorly known killer whale ecotype, type D killer whales are of interest to many scientists. Fresh genetic samples hold the answers to questions that many people have been asking since their discovery in 1955.

A new study, published recently in the Journal of Heredity, provides insight into the genetics of the type D killer whale: https://academic.oup.com/jhered/advance-article/doi/10.1093/jhered/esac070/7086686

Here are some takeaways:

1: Type D killer whales are the MOST inbred killer whales on the planet, and are one of the most inbred mammals EVER documented!

2: They have been inbreeding for a long time and have extremely low genetic diversity, similar to that of the vaquita, of which there are less than 10 individuals remaining.

3: Their bizarre appearance—the bulbous heads and minuscule eye patches—may be due to the fact they are so inbred!

So…are they a new species? That’s the tantalizing question we’ve all been asking. Based on this new analysis, there’s some strong evidence that supports the notion of type D killer whales as a distinct species. The paper points out that their long-term inbreeding and lack of connection with other killer whales—both genetically and socially—means it’s time to take a closer look at their taxonomic standing. If they are to be made a distinct species, scientists will need to write up a separate paper laying out all of the evidence that supports designating them as their own species, and will also need to come up with a proposed scientific name for the species.

The lead author Dr. Andrew Foote was kind enough to invite me to write an accompanying blog post about the paper for the Journal of Heredity—watch this space, as I will share it whenever it gets posted. Thank you Andy for letting me take a peek at the manuscript a few months in advance! (I have been so excited to talk about this, you have NO idea!)

[northernnaturalist]

Being a mother is no easy feat, especially if you are a killer whale!

They have one of the longest gestation periods of any animal at an astounding 16-18 months, and during this time period, they gain 500-600 pounds! A female may eat a little bit more while she’s pregnant, but the real work begins once the calf is born. Lactation is one of the most energetically expensive processes a mammal can undertake. For a female killer whale, the nursing demands of a calf can result in her increasing her food intake by 50% to 100% percent. Calves can start taking solid food at about six months but continue to nurse from their mothers for up to 1-2 years before becoming completely weaned.

Killer whales are slow to reproduce. While some particularly productive females may have a calf every 2 years, on average, females wait about 5 years between calves. This means a single female may only produce 5-6 calves in her lifespan. If a female suffers from stillbirths or miscarriages, the total number of pregnancies may be higher; for example, southern resident J31 Tsuchi was pregnant at least 7 times in a nine-year period, but only one of these pregnancies resulted in a healthy, live calf. The southern residents in particular have a difficult time maintaining pregnancies. A 2017 study found that up almost 70% of their pregnancies result in miscarriages or stillbirths as a result of inadequate Chinook salmon availability.

References:

Kriete, B. (1994). Bioenergetics in the killer whale, Orcinus orca (T). University of British Columbia

Wasser SK, Lundin JI, Ayres K, Seely E, Giles D, Balcomb K, et al. (2017) Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca). PLoS ONE 12(6): e0179824

[northernnaturalist]

There’s not much that scares a killer whale. After all, it is a top predator capable of feeding on virtually any animal in the ocean. But there is one creature that can intimidate even killer whales—pilot whales.

In various parts of the world, long-finned pilot whales have been documented approaching and even chasing groups of killer whales. These interactions have occurred in Norway, Iceland, Spain, and there are anecdotal reports from Australia. Pilot whales may come charging into the area, harassing and pursuing a group of killer whales, which often respond by moving away and even fleeing at high speeds. I’ll never forget the day in Norway a few years ago when I was stuck at the house, unable to head out on the water for observations. On that particular day, a massive group of pilot whales appeared in the fjords, and the killer whales in the area all vanished for the rest of the day. The pilot whales had left by the following morning, and we managed to find a few killer whales that had returned, but it certainly gave me a lot to think about.

Curiously, pilot whales are attracted to killer whale calls, and upon hearing them, will respond by approaching the source of the sound, which may explain why they sometimes seemingly appear out of nowhere and start chasing the killer whales. Scientists suggest this behavior could be an anti-predator response to killer whales. Aggressively approaching the killer whales may be pilot whales’ way of saying “Hey, I can see you, get away from here!” There also may be some aspect of food competition, but this seems like a less likely reason as the diet of pilot whales and killer whales do not always overlap.

Another potentially important piece of this puzzle was revealed earlier this year when researchers in Iceland documented a tiny newborn pilot whale traveling with a pod a killer whales, with no other pilot whales in sight. Are killer whales calf-napping baby pilot whales?! There’s still much to be learned about these interactions.

References:

Curé C, Antunes R, Samarra F, Alves AC, Visser F, Kvadsheim PH, Miller PJO (2012) Pilot whales attracted to killer whale sounds: acoustically-mediated interspecific interactions in cetaceans. PLoS ONE 7:e52201.

Selbmann, A., Basran, C.J., Bertulli, C.G. et al. (2022) Occurrence of long-finned pilot whales (Globicephala melas) and killer whales (Orcinus orca) in Icelandic coastal waters and their interspecific interactions. acta ethol 25, 141–154

[northernnaturalist]

Sometimes, newborn killer whales get a rough start to life.

Every now and then, scientists document newborn killer whales with intense or prolific scarring on their bodies. These scars, also called rake marks, are caused by other killer whales biting the calves or dragging their teeth across their skin. It is common for killer whales of all ages to have rake marks to some degree, though some newborn calves have very deep scars. While the origin of the scars are clear, the reasons why they were inflicted are more difficult to uncover.

Aggression from other killer whales is a likely explanation for many cases of these scars. Scientists have observed calf-directed aggression in both fish-eating and mammal-eating populations of killer whales in different parts of the world. There is at least one case of transient killer whales committing infanticide. Additionally, infant-directed aggression is common in other species of social mammals, so it is not surprising to note that it can occur in killer whales. A recent study showed that in the southern resident killer whales population, rake mark density is highest in calves and juveniles. Some rakes may come from rough and tumble play, but may also result from competition with their siblings for access to food.

In one case, scientists observed killer whales supporting an ailing calf—southern resident J54 lost his mother before he was weaned, and as a result, rapidly declined in health. His body was covered in rake marks from his sister and other relatives using their mouths and teeth to support him at the surface of the water. These rakes appeared to be fairly shallow, however, so deeper rake marks on calves may have a different cause.

What about “orca midwives?” Several years ago, a southern resident killer whale, J50, was sighted shortly after birth with long, deep scars across her back. It was hypothesized that she had a difficult birth, and was “pulled out” of the birth canal by other killer whales using their teeth. While it’s certainly a heartwarming idea, there is so far no evidence to support the notion of “midwifery” in killer whales.

Reference: Grimes, C., Brent, L. J. N., Weiss, M. N., Franks, D. W., Balcomb, K. C., Ellifrit, D. K., Ellis, S., & Croft, D. P. (2022). The effect of age, sex, and resource abundance on patterns of rake markings in resident killer whales (Orcinus orca). Marine Mammal Science, 38( 3), 941– 958.

[northernnaturalist]

Notable Males From The West Coast Transient (Bigg’s) Killer Whale Population

There are so many interesting whales in the West Coast transient population, and many of them have particularly unique stories and backgrounds. Here is a selection of notable males from this population:

First up, Charlie Chin! He is no longer alive, but remains one of the most physically unique males, and was briefly held in captivity before being released.

T068A “Ken” is arguably the most infamous—he and his mother committed the only documented act (so far) of infanticide in killer whales.

T011A “Rainy” is the largest measured whale in this population, and at over 27 feet in length, is also one of the largest recorded killer whales overall. Only a few whales have been measured at greater lengths.

T087 “Harbeson” is the oldest male in the population. At 60 years old, he has far outlived the average life expectancy of a male killer whale, which is around 30 years.

Finally, we have T063 “Chainsaw.” He is instantly recognizable and most whale watchers on the West Coast have this male on their “must see” list!

The stories of these whales are only able to be told thanks to the decades of work done by the biologists at Fisheries and Oceans Canada, Bay Cetology, The Center for Whale Research, the North Gulf Oceanic Society, and countless others.

References:

Pacific Whale Watch Association

Podt, A. (2017). A Special Family, the T2s. Orcazine.

Kotik, C. (2020). Aerial photogrammetry to estimate size, growth, and body condition of mammal-eating Bigg’s killer whales. UC San Diego.

Towers, J.R., Hallé, M.J., Symonds, H.K. et al. (2018) Infanticide in a mammal-eating killer whale population. Sci Rep 12, 6418

Towers, J.R., Sutton, G.J., Shaw, T.J.H., Malleson, M., Matkin, D., Gisborne, B., Forde, J., Ellifrit, D., Ellis, G.M., Ford, J.K.B., and Doniol-Valcroze, T. 2019. Photo-identification Catalogue, Population Status, and Distribution of Bigg’s Killer Whales known from Coastal Waters of British Columbia, Canada. Can. Tech. Rep. Fish. Aquat. Sci. 3311: vi + 299 p

[northernnaturalist]

Killer Whales of Sri Lanka

Sri Lanka is probably not the first country you think of when you hear “killer whales.” But indeed, they can be found cruising the waters off this island nation if you look hard enough.

Research on Sri Lanka’s killer whales is still in its infancy. Back in 2013, Orca Project Sri Lanka (OPSL) was born, a community science effort founded by scientists in order to learn more about the killer whales around Sri Lanka. They began with only 9 photo-identified individuals, but thanks to the work of photographers, community members, and whale watching companies, the catalog stands at 39 individuals as of 2019.

The project has provided insight into the lives of these mysterious killer whales. Like other killer whales in tropical areas, Sri Lanka’s killer whales are a bit brownish in color, posses very faint saddle patches, and have somewhat shorter dorsal fins compared to their northern counterparts. Information on their diet is scant, but there are records of them preying on sperm whales and beaked whales (and there’s a chance they may go after blue whales on rare occasions).

For several years, the range and movements of these killer whales remained a mystery. Were they “resident” to Sri Lanka, or did they venture elsewhere in the Indian Ocean? In 2015, OPSL discovered one pod of Sri Lankan killer whales, pod 6, had actually been seen in 2008 near Dubai in the United Arab Emirates. In 2019, those same whales were documented making the 3,300 kilometer trip a second time. Why might these whales be traveling such long distances? Right now, it remains a mystery.

References:

Gemmell, G., de Silva Wijeyeratne, G. & Jayatilake. C. (2019). Orcas of Sri Lanka: A Catalogue of Photo-identified individuals. Orca Project Sri Lanka. Online Publication. Released 7 January 2019.

Gemmell, G. L., McInnes, J. D., Heinrichs, S. J., & Wijeyeratne, G. de S. (2015). Killer whale (Orcinus orca) predation on whales in Sri Lankan waters. Aquatic Mammals, 41(3), 265–271

[northernnaturalist]

Killer Whales of Japan

Off Japan’s northernmost island of Hokkaido, killer whales roam the seas.

Research on the killer whales in Japan is relatively new, so nobody is sure yet how many exist, and how they relate to the killer whale populations in Russia just to the north. Recently, scientists collected genetic samples of killer whales in northern Japan and confirmed both transient and resident killer whales are present, much like in other parts of the North Pacific Ocean. Killer whales are also occasionally seen in the tropical region of Okinawa, but these are probably different from the whales found in northern Japan.

In the aftermath of World War II, Japan relied on whaling to provide animal protein to its people—this also included killer whales. From 1948-1957, Japan captured 567 killer whales in its waters, primarily around the northern island of Hokkaido. As killer whales are long-lived animals and are slow to reproduce, this almost certainly had a significant effect on local killer whale populations. Today, Japan does not hunt killer whales—rather, they have become the focus of whale watching operations and scientific studies in northern Japan. Sight-seeing tours carry tourists and visitors out into the waters of Hokkaido to view pods of killer whales that frequent the area in the early summer months.

Curiously, white killer whales have also been seen in Japan, as recently as 2021. The cause of the the abnormal coloration is unknown, but it is likely some form of albinism. Similar white killer whales have been documented in nearby Russian waters, but have not yet been matched to the white whales seen in Japan.