Orca

In this episode of the I Can't Sleep Podcast, fall asleep learning about Orcas. While these are some of the most intelligent mammals on earth, it is way too boring to learn about them; good luck on this one. Happy sleeping!

Transcript

Welcome to the I Can't Sleep podcast,

Where I read random articles from across the web to bore you to sleep with my soothing voice.

I'm your host,

Benjamin Boster.

Today's episode is from a Wikipedia article titled,

Orca.

The orca,

Orcinus orca,

Or killer whale,

Is a toothed whale that is the largest member of the oceanic dolphin family.

It is the only extant species in the genus Orcinus.

Orcas are recognizable by their black and white patterned body.

A cosmopolitan species,

Orcas are found in diverse moraine environments,

From Arctic to Arctic regions to tropical seas.

Orcas are apex predators with a diverse diet.

Individual populations often specialize in particular types of prey.

This includes a variety of fish,

Sharks,

Rays,

And moraine mammals such as seals,

Other species of dolphin,

And whales.

They are highly social.

Some populations are composed of highly stable matrilineal family groups,

Pods.

Their sophisticated hunting techniques and vocal behaviors,

Often specific to a particular group and passed along from generation to generation,

Are considered to be manifestations of animal culture.

The International Union for Conservation of Nature assesses the orca's conservation status as data deficient because of the likelihood that two or more orca types are separate species.

Some local populations are considered threatened or endangered due to prey depletion,

Habitat loss,

Pollution by PCBs,

Capture for moraine mammal parks,

And conflicts with human fisheries.

In late 2005,

The southern resident orcas,

Which swim in British Columbia and Washington waters,

Were placed on the U.

S.

Endangered species list.

Orcas are commonly referred to as killer whales,

Despite being a type of dolphin.

Since the 1960s,

The use of orca instead of killer whale has steadily grown in common use.

The genus name orcinus means of the kingdom of the dead,

Or belonging to orcas.

Ancient Romans originally used orca for these animals,

Possibly borrowing ancient Greek oryx.

This word referred,

Among other things,

To a whale species,

Perhaps a narwhal.

As part of the family Delphinidae,

The species is more closely related to other oceanic dolphins than to other whales.

They are sometimes referred to as blackfish,

A name also used for other whale species.

Grampus is a former name for the species,

But is now seldom used.

This meaning of grampus should not be confused with the genus Grampus,

Whose only member is Rizzo's dolphin.

This orca is the only recognized xtant species in the genus Orcinus,

And one of many animal species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae.

Conrad Gessner wrote his first scientific description of an orca in his Piscium and Aquatilium Animatium Naturae in 1558,

Part of the larger Historia Animalium,

Based on examination of dead stranded animal in the bay of Greifswald,

That it attracted a great deal of local interest.

The orca is one of 35 species in the oceanic dolphin family,

Which first appeared about 11 million years ago.

The orca lineage probably branched off shortly thereafter.

Although it has morphologically similarities with the false killer whale,

The pygmy killer whale and the pilot whales,

A study of cytochrome B gene sequences,

Indicates that its closest xtant relatives are the snubfin dolphins of the genus Orcilla.

The three to five types of orcas may be distinct enough to be considered different races,

Subspecies,

Or possibly even species.

The IUCN reported in 2008,

The taxonomy of this genus is clearly in need of review,

And it is likely that O orca will be split into a number of different species,

Or at least subspecies over the next few years.

Although large variation in the ecological distinctiveness of different orca groups complicates simple differentiation into types,

Research off the west coast of North America has identified fish-eating residents,

Mammal-eating transients,

And offshores.

Other populations have not been as well studied,

Although specialized fish and mammal-eating orcas have been distinguished elsewhere.

Mammal-eating orcas in different regions were long thought likely to be closely related,

But genetic testing has refuted this hypothesis.

Four types have been documented in the Antarctic,

Types A through D.

Two dwarf species named Orcinus nanus and Orcinus glacialis were described during the 1980s by Soviet researchers,

But most cetacean researchers are skeptical about their status.

Complete mitochondrial sequencing indicates that two Antarctic groups,

Types B and C,

Should be recognized as distinct species,

As should the North Pacific transients,

Leaving the others as subspecies,

Pending additional data.

A 2019 study of type D orcas also found them to be distinct from other populations and possibly even a unique species.

Orcas are the largest extant members of the dolphin family.

Males typically range from 6 to 8 meters long and weigh in excess of 6 tons.

Females are smaller,

Generally ranging from 5 to 7 meters and weighing about 3 to 4 tons.

Orcas may attain larger sizes as males have been recorded at 9.

8 meters and females at 8.

5 meters.

Calves at birth weigh about 180 kilograms and are about 2.

4 meters long.

The skeleton of the orca is typically for an oceanic dolphin but more robust.

With their distinctive pigmentation,

Adult orcas are seldom confused with any other species.

When seen from a distance,

Juveniles can be confused with false killer whales or rhysos dolphins.

The orca typically has a sharply contrasted black and white body,

Being mostly black on the upper side and white on the underside.

The tail fluke fin is also white on the underside while the eyes have white oval-shaped patches behind and above them,

And a gray or white saddle patch exists behind the dorsal fin and across the back.

In newborns,

The white areas are yellow or orange-colored.

Antarctic orcas may have pale gray to nearly white backs.

Some Antarctic orcas are brown and yellow due to diatoms in the water.

Both albino and melanistic orcas have been documented.

Orca pectoral fins are large and rounded,

Resembling paddles with those of males significantly larger than those of females.

In the skull,

Adult males have longer lower jaws than females,

As well as larger occipital crests.

The snout is blunt and lacks the beak of other species.

The orca's teeth are very strong and its jaws exert a powerful grip.

The upper teeth fall into the gaps between the lower teeth when the mouth is closed.

The firm middle and back teeth hold prey in place,

While the front teeth are inclined slightly forward and outward to protect them from powerful jerking movements.

Orcas have good eyesight above and below the water,

Excellent hearing,

And a good sense of touch.

They have exceptionally sophisticated echolocation abilities,

Detecting the location and characteristics of prey and other objects in the water by emitting clicks and listening for echoes,

As do other members of the dolphin family.

The main body temperature of the orca is 36 to 38 degrees Celsius.

Like most marine mammals,

Orcas have a layer of insulating blubber ranging from 7.

6 to 10 centimeters thick beneath the skin.

The pulse is about 60 heartbeats per minute when the orca is at the surface,

Dropping to 30 beats per minute when submerged.

An individual orca can often be identified from its dorsal fin and saddle patch.

Variations such as nicks,

Scratches,

And tears on the dorsal fin and the pattern of white or gray in the saddle patch are unique.

Published directories contain identifying photographs and names for hundreds of North Pacific animals.

Photographic identification has enabled the local population of orcas to be counted each year rather than estimated,

And has enabled great insight into life cycles and social structures.

Orcas are found in all oceans and most seas.

Due to their enormous range,

Numbers,

And density,

Relative distribution is difficult to estimate,

But they clearly prefer higher latitudes in coastal areas over pelagic environments.

Areas which serve as major study sites for the species include the coasts of Iceland,

Norway,

The Valdez Peninsula of Argentina,

The Crozet Islands,

New Zealand,

And parts of the west coast of North America,

From California to Alaska.

Systematic surveys indicate the highest density of orcas in the Northeast Atlantic around the Norwegian coast in the North Pacific along the Aleutian Islands,

The Gulf of Alaska,

And in the Southern Ocean off much of the coast of Antarctica.

They are considered common in the Eastern Pacific along the coasts of British Columbia,

Washington,

And Oregon,

In the North Atlantic Ocean around Iceland and the Faroe Islands.

In the Arctic,

Orcas range up to the edge of the pack ice and are believed to venture into the denser pack ice,

Finding open leads much like beluga whales in the Arctic.

However,

Orcas are merely seasonal visitors to Arctic waters and do not approach the pack ice in the summer.

With the rapid Arctic sea ice decline in the Hudson Strait,

Their range now extends deep into the Northwest Atlantic.

Occasionally,

Orcas swim into freshwater rivers.

They have been documented 100 miles up the Columbia River in the United States.

They have also been found in the Fraser River in Canada and the Horikawa River in Japan.

Migration patterns are poorly understood.

Each summer,

The same individuals appear off the coasts of British Columbia and Washington.

Despite decades of research,

Where these animals go for the rest of the year remains unknown.

Transient pods have been sighted from southern Alaska to central California.

Worldwide population estimates are uncertain,

But recent censuses suggest a minimum of 50,

000.

Local estimates include roughly 25,

000 in the Antarctic,

8,

500 in the tropical Pacific,

2,

250 to 2,

700 off the cooler northeast Pacific,

And 500 to 1,

500 off Norway.

Japan's fisheries agency estimated in the 2000s that 2,

321 orcas were in the seas around Japan.

Orcas are apex predators,

Meaning that they themselves have no natural predators.

They are sometimes called wolves of the sea because they hunt in groups like wolf packs.

Orcas hunt varied prey including fish,

Cephalopods,

Mammals,

Seabirds,

And sea turtles.

Some populations or ecotypes may specialize,

And some can have a dramatic impact on prey species.

However,

Whales in tropical areas appear to have more generalized diets due to lower food productivity.

Orcas spend most of their time at shallow depths,

But occasionally dive several hundred meters depending on their prey.

Fish-eating orcas prey on around 30 species of fish.

Some populations in the Norwegian and Greenland Seas specialize in herring and follow that fish's autumnal migration to the Norwegian coast.

Salmon account for 96% of Northeast Pacific residents' diet,

Including 65% of large,

Fatty chinook.

Chum salmon are also eaten,

But smaller sockeye and pink salmon are not a significant food item.

Depletion of specific prey species in an area is therefore a cause for concern for local populations,

Despite the high diversity of prey.

On average,

An orca eats 227 kilograms,

500 pounds,

Each day.

While salmon are usually hunted by an individual whale or a small group,

Herring are often caught using carousal feeding.

The orcas force the herring into a tight ball by releasing bursts of bubbles or flashing their white underside.

They then slap the ball with their tail flukes,

Stunning or killing up to 15 fish at a time,

Then eating them one by one.

Carousel feeding has only been documented in the Norwegian orca population,

As well as some oceanic dolphin species.

Some dolphins recognize fish-eating orcas,

Usually resident,

As harmless and remain in the same area.

In New Zealand,

Sharks and rays appear to be important prey,

Including eagle rays,

Long-tail and short-tail stingrays,

Common threshers,

Smooth hammerheads,

Blue sharks,

Basking sharks,

And shortfin makos.

With sharks,

Orcas may herd them to the surface and strike them with their tail flukes,

While bottom-dwelling rays are cornered,

Pinned to the ground,

And taken to the surface.

In other parts of the world,

Orcas have preyed on broadnose sevengill sharks,

Small whale sharks,

And even great white sharks.

Competition between orcas and white sharks is probably in regions where their diets overlap.

The arrival of orcas in an area can cause white sharks to flee and forage elsewhere.

Orcas appear to target the liver of sharks.

Orcas are sophisticated and effective predators of marine mammals.

They are recorded to prey on other cetacean species,

Usually smaller dolphins and porpoises such as common dolphins,

Bottlenose dolphins,

Pacific white-sided dolphins,

Tusky dolphins,

Harbor porpoises,

And dolls porpoises.

Day-to-day orca behavior generally consists of foraging,

Traveling,

Resting,

And socializing.

Orcas frequently engage in surface behavior such as breaching,

Jumping completely out of the water,

And tail slapping.

These activities may have a variety of purposes,

Such as courtship,

Communication,

Dislodging parasites,

Or play.

Spy-hopping is a behavior in which a whale holds its head above water to view its surroundings.

Resident orcas swim alongside porpoises and other dolphins.

Orcas are notable for their complex societies.

Only elephants and higher primates live in comparably complex social structures.

Due to orcas' complex social bonds,

Many marine experts have concerns about how humane it is to keep them in captivity.

Resident orcas in the eastern North Pacific live in particularly complex and stable social groups.

Unlike any other known mammal social structure,

Resident whales live with their mothers for their entire lives.

These family groups are based on matrilines consisting of the eldest female,

Matriarch,

And her sons and daughters,

And the descendants of her daughters,

Etc.

The average size of a matriline is 5.

5 animals.

Those females can reach age 90,

As many as four generations travel together.

These matrilineal groups are highly stable.

Individuals separate for only a few hours at a time to mate or forage.

With one exception,

An orca named Luna,

No permanent separation of an individual from a resident matriline has been recorded.

Closely related matrilines form loose aggregations called pods,

Usually consisting of one to four matrilines.

Unlike matrilines,

Pods may separate for weeks or months at a time.

DNA testing indicates resident males nearly always mate with females from other pods.

Clans,

The next level of resident social structure,

Are composed of pods with similar dialects and common but older maternal heritage.

Clan ranges overlap,

Mingling pods from different clans.

The highest association layer is the community,

Which consists of pods that regularly associate with each other,

But share no maternal relations or dialects.

Transient pods are smaller than resident pods,

Typically consisting of an adult female and one or two of her offspring.

Males typically maintain stronger relationships with their mothers than other females.

These bonds can extend well into adulthood.

Unlike residents,

Extended or permanent separation of transient offspring from natal matrilines is common,

With juveniles and adults of both sexes participating.

Some males become rovers and do not form long-term associations,

Occasionally joining groups that contain reproductive females.

As in resident clans,

Transient community members share an acoustic repertoire,

Although regional differences in vocalizations have been noted.

As with residents and transients,

The lifestyle of these whales appears to reflect their diet.

Fish-eating orcas off Norway have resident-like social structures,

While mammal-eating orcas in Argentina and the Crosset Islands behave more like transients.

Orcas of the same sex and age group may engage in physical contact and synchronous surfacing.

These behaviors do not occur randomly among individuals in a pod,

Providing evidence of friendships.

Like all cetaceans,

Orcas depend heavily on underwater sound for orientation,

Feeding,

And communication.

They produce three categories of sounds—clicks,

Whistles,

And pulsed calls.

Clicks are believed to be used primarily for navigation and discriminating prey and other objects in the surrounding environment,

But are also commonly heard during social interactions.

Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters.

Residents feed primarily on chinook and chum salmon,

Which are insensitive to orca calls inferred from the audiogram of Atlantic salmon.

In contrast,

The marine mammal prey of transients hear whale calls well,

And thus transients are typically silent.

Vocal behavior in these whales is mainly limited to surfacing activities and milling—slow swimming with no apparent direction after a kill.

All members of a resident pod use similar calls,

Known collectively as a dialect.

Dialects are composed of specific numbers and types of discrete,

Repetitive calls.

They are complex and stable over time.

Call patterns and structure are distinctive within matrilines.

Newborns produce calls similar to their mothers,

But have a more limited repertoire.

Individuals likely learn their dialect through contact with pod members.

Family-specific calls have been observed more frequently in the days following a calf's which may help the calf learn them.

Dialects are probably an important means of maintaining group identity and cohesiveness.

Similarity in dialects likely reflects the degree of relatedness between pods,

With variation growing over time.

When pods meet,

Dominant call types decrease and subset call types increase.

The use of both call types is called bifonation.

The increased subset call types may be the distinguishing factor between pods and interpod relations.

Dialects also distinguish types.

Resident dialects contain 7 to 17 distinctive call types.

All members of the North American West Coast Transient Community express the same basic dialect,

Although minor regional variation in call types is evident.

Preliminary research indicates offshore orcas have group-specific dialects,

Unlike those of residents and transients.

Norwegian and Icelandic herring-eating orcas appear to have different vocalizations for activities like hunting.

A population that live in McMurdo Sound,

Antarctica,

Have 28 complex burst,

Pulse,

And whistle calls.

Orcas have the second-heaviest brains among marine mammals,

After sperm whales,

Which have the largest brain of any animal.

Orcas have more gray matter and more cortical neurons than any mammal,

Including humans.

They can be trained in captivity and are often described as intelligent,

Although defining and measuring intelligence is difficult in a species whose environment and behavioral strategies are very different from those of humans.

Orcas imitate others and seem to deliberately teach skills to their kin.

Off the Crosset Islands,

Mothers push their calves onto the beach,

Waiting to pull the youngster back if needed.

In March 2023,

A female orca was spotted with a newborn pilot whale in Snyfelsness.

People who have interacted closely with orcas offer numerous anecdotes demonstrating the whale's curiosity,

Playfulness,

And ability to solve problems.

Alaskan orcas have not only learned how to steal fish from longlines,

But have also overcome a variety of techniques designed to stop them,

Such as the use of unbaited lines as decoys.

Once fishermen placed their boats several miles apart,

Taking turns retrieving small amounts of their catch,

In the hope that the whales would not have enough time to move between boats to steal the catch as it was being retrieved.

The tactic worked initially,

But the orcas figured it out quickly and split into groups.

In other anecdotes,

Researchers describe incidents in which wild orcas playfully tease humans by repeatedly moving objects the humans are trying to reach,

Or suddenly start to toss around a chunk of ice after a human throws a snowball.

The orcas' use of dialects and the passing of other learned behaviors from generation to generation have been described as a form of animal culture.

The complex and stable vocal and behavioral cultures of sympatric groups of killer whales appear to have no parallel outside humans and represent an independent evolution of cultural faculties.

Female orcas begin to mature at around the age of 10 and reach peak fertility around 20,

Experiencing periods of polyostrous cycling separated by non-cycling periods of 3-16 months.

Females can often breed until age 40,

Followed by a rapid decrease in fertility.

Orcas are among the few animals that undergo menopause and live for decades after they have finished breeding.

The lifespan of wild females average 50-80 years.

Some are claimed to have lived substantially longer.

Granny,

J2,

Was estimated by some researchers to have been as old as 105 years at the time of her death,

Though a biopsy sample indicated her age as 65-80 years.

It is thought that orcas held in captivity tend to have shorter lives than those in the wild,

Although this is subject to scientific debate.

Materials made with females from other pods,

Which prevents inbreeding,

Gestation varies from 15-18 months.

Mothers usually calve a single offspring about once every 5 years.

In resident pods,

Births occur at any time of year,

Although winter is the most common.

Mortality is extremely high during the first 7 months of life,

When 37-50% of all calves die.

Breeding begins at about 12 months of age and is complete by 2 years.

According to observations in several regions,

All male and female pod members participate in the care of the young.

Males sexually mature at the age of 15,

But do not typically reproduce until age 21.

Wild males live around 29 years on average,

With a maximum of about 60 years.

One male,

Known as Old Tom,

Was reportedly spotted every winter between the 1840s and 1930s off New South Wales,

Australia,

Which would have made him up to 90 years old.

Examination of his teeth indicated he died around age 35,

But this method of age determination is now believed to be inaccurate for older animals.

One male,

Known to researchers in the Pacific Northwest,

Was estimated to have been 59 years old when he died in 2010.

Orcas are unique among cetaceans as their caudal sections elongate with age,

Making their heads relatively shorter.

In 2008,

The IUCN,

International Union for Conservation of Nature,

Changed its assessment of the orca's conservation status from conservation-dependent to data-deficient,

Recognizing that one or more orca types may actually be separate,

Endangered species.

Depletion of prey species,

Pollution,

Large-scale oil spills,

And habitat disturbance caused by noise and conflict with boats are the most significant worldwide threats.

In January 2020,

The first orca in England and Wales since 2001 was found dead with a large fragment of plastic in its stomach.

Like other animals at the highest trophic levels,

The orca is particularly at risk of poisoning from bioaccumulation of toxins,

Including polychlorinated biphenyls,

PCBs.

European harbor seals have problems in reproductive and immune functions associated with high levels of PCBs and related contaminants,

And a survey off the Washington coast found PCB levels in orcas were higher than levels that had caused health problems in harbor seals.

Blubber samples in the Norwegian Arctic show higher levels of PCBs,

Pesticides,

And brominated flame retardants than in polar bears.

A 2018 study published in Science found that global orca populations are poised to dramatically decline due to such toxic pollution.

In the Pacific Northwest,

Wild salmon stocks,

A main resident food source,

Have declined dramatically in recent years.

In the Puget Sound region,

Only 75 whales remain with few births over the last few years.

On the west coast of Alaska and the Aleutian Islands,

Seal and sea lion populations have also substantially declined.

In 2005,

The United States government listed the southern resident community as an endangered population under the Endangered Species Act.

This community comprises three pods which live mostly in Georgia and Haro Straits and Puget Sound in British Columbia and Washington.

They do not breed outside of their community,

Which was once estimated at around 200 animals and later shrank to about 90.

In October 2008,

The annual survey revealed seven were missing and presumed dead,

Reducing the count to 83.

This is potentially the largest decline in the population in the past 10 years.

These deaths can be attributed to declines in Chinook salmon.

Scientist Ken Balcombe has extensively studied orcas since 1976.

He is the research biologist responsible for discovering U.

S.

Navy sonar may harm orcas.

He studied orcas from the Center for Whale Research located in Friday Harbor,

Washington.

He was also able to study orcas from his home porch perched about Puget Sound,

Where the animals hunt and play in summer months.

In May 2003,

Balcombe,

Along with other whale watchers near the Puget Sound coastline,

Noticed uncharacteristic behavior displayed by orcas.

The whales seemed agitated and were moving haphazardly,

Attempting to lift their heads free of the water to escape the sound of the sonars.

Balcombe confirmed at the time that strange underwater pinging noises detected with underwater microphones were sonar.

The sound originated from a U.

S.

Navy frigate 12 miles distant,

Balcombe said.

The impact of sonar waves on orcas is potentially life-threatening.

Three years prior to Balcombe's discovery,

Research in the Bahamas showed 14 beaked whales washed up on the shore.

These whales were beached on the day U.

S.

Navy destroyers were activated into sonar exercise.

Of the 14 whales beached,

Six of them died.

These six dead whales were studied,

And CAD scans of two of the whale heads showed hemorrhaging around the brain and the ears,

Which is consistent with decompression sickness.

Another conservation concern was made public in September 2008 when the Canadian government decided it was not necessary to enforce further protections,

Including the Species at Risk Act in place to protect endangered animals along with their habitats for orcas aside from the laws already in place.

In response to this decision,

Six environmental groups sued the federal government,

Claiming orcas were facing many threats on the British Columbia coast,

And the federal government did nothing to protect them from these threats.

A legal and scientific non-profit organization,

Ecojustice,

Led the lawsuit and represented the David Suzuki Foundation,

Environmental Defense,

Greenpeace Canada,

International Fund for Animal Welfare,

The Raincoast Conservation Foundation,

And the Wilderness Committee.

Many scientists involved in this lawsuit,

Including Bill Wareham,

A marine scientist with the David Suzuki Foundation,

Noted increased boat traffic,

Water-toxic wastes,

And low salmon population as major threats,

Putting approximately 87 orcas on the British Columbia coast in danger.

Underwater noise from shipping,

Drilling,

And other human activities is a significant concern in some key orca habitats,

Including Johnstone Strait and Harrow Strait.

In the mid-1990s,

Loud underwater noises from salmon farms were used to deter seals.

Orcas also avoided the surrounding waters.

High-intensity sonar used by the Navy disturbs orcas along with other marine mammals.

Orcas are popular with whale watchers,

Which may stress the whales and alter their behavior,

Particularly if boats approach too closely or block their lines of travel.

The indigenous peoples of the Pacific Northwest Coast feature orcas throughout their art,

History,

Spirituality,

And religion.

The Haida regarded orcas as the most powerful animals in the ocean,

And their mythology tells of orcas living in houses and towns under the sea.

According to these myths,

They took on human form when submerged,

And humans who drowned went to live with them.

For the Kwakwaka'wakw,

The orca was regarded as the ruler of the undersea world,

With sea lions for slaves and dolphins for warriors.

The Nuu-chah-nulth and the Kwakwaka'wakw mythology,

Orcas may embody the souls of deceased chiefs.

The Tlingit of southeastern Alaska regarded the orca as custodian of the sea and a benefactor of humans.

The Lumi considered orca to be people,

Referring to them as kwel'almachin,

Which means our relations under the waves.

The Maritime Archaic people of Newfoundland also had great respect for orcas,

As evidenced by stone carvings found in a 4,

000-year-old burial at the Port-au-Choix archaeological site.

In the tales and beliefs of the Siberian Yupik people,

Orcas are said to appear as wolves,

In winter,

And wolves as orcas,

In summer.

Orcas are believed to assist their hunters in driving walrus.

Reverence is expressed in several forms.

The boat represents the animal,

And a wooden carving hung from the hunter's belt.

Small sacrifices,

Such as tobacco or meat,

Are strewn into the sea for them.

The Ainu people of Hokkaido,

The Kuril Islands,

And the southern Sakhalin often referred to orcas in their folklore and myth as repun kamayu,

God of sea,

Offshore,

To bring fortunes,

Whales,

To the coasts.

And there had been traditional funerals for stranded or deceased orcas akin to funerals for other animals,

Such as brown bears.

In Western cultures,

Orcas were historically feared as dangerous,

Savage predators.

The first written description of an orca was given by Pliny the Elder around A.

D.

70,

Who wrote,

Orcas,

The appearance of which no image can express,

As are then an enormous mass of savage flesh with teeth,

Are the enemy of other kinds of whale.

They charge and pierce them like warships ramming.

On the very few confirmed attacks on humans by wild orcas,

None have been fatal.

In one instance,

Orcas tried to tip ice flows in which a dog team and photographer of the Terra Nova expedition were standing.

The sled dog's barking is speculated to have sounded enough like seal calls to trigger the orca's hunting curiosity.

In the 1970s,

A surfer in California was bitten,

And in 2005,

A boy in Alaska who was splashing in a region frequented by harbor seals was bumped by an orca that apparently misidentified him as prey.

Unlike wild orcas,

Captive orcas have made nearly two dozen attacks on humans since the 1970s,

Some of which have been fatal.

Whale-watching continues to increase in popularity,

But may have some problematic impacts on orcas.

Exposure to exhaust gases from large amounts of vessel traffic is causing concern for the overall health of the 75 remaining southern resident orcas left as of early 2019.

This population is followed by approximately 20 vessels for 12 hours a day during the month May through September.

Researchers discovered that these vessels are in the line of sight for these whales for 98-99.

5% of daylight hours.

With so many vessels,

The air quality around these whales deteriorates and impacts their health.

Air pollutants that bind with exhaust fumes are responsible for the activation of the cytochrome P4501A gene family.

Researchers have successfully determined this gene in skin biopsies of live whales and also the lungs of deceased whales.

A direct correlation between activation of this gene and the air pollutants cannot be made because there are other known factors that will induce the same gene.

Vessels can have either wet or dry exhaust systems,

With wet exhaust systems leaving more pollutants in the water due to various gas solubility.

A modeling study determined that the lowest observed adverse effect level,

LOAEL,

Of exhaust pollutants was about 12% of the human dose.

As a response to this,

In 2017 boats off the British Columbia coast now have a minimum approach distance of 200 meters compared to the previous 100 meters.

This new rule complements Washington state's minimum approach zone of 180 meters that has been in effect since 2011.

If a whale approaches a vessel,

It must be placed in neutral until the whale passes.

The World Health Organization has set air quality standards in an effort to control the emissions produced by these vessels.

Reviews

It's too bad that I never get to hear all of it. Thanks so much!

As always an excellent way to fall asleep 😴 I have to say: I miss the intro music. I loved the original intro music the best, but also liked the updated intro music. The readings are just as good as ever, but without music it's a wee bit harsher of an opening. Thank you for what you do, I listen almost every night 🙏✨