Do coelacanths hold a priceless secret to longevity?
Given it’s been swimming our oceans for around 360 million years, it’s a fair bet that it’s mastered the cream of core survival skills.
Perhaps its ability to keep a low profile is part of its strategy…
Science believed it was extinct until a living specimen was caught in 1938…
Let me show you what those scholars discovered.
Introduction: Back From The Dead?
Before 1938, our only knowledge of the coelacanth or latimeria chalumnae came from fossils…
As you might expect…
Hauling up a fish that has supposedly gone extinct sent a host of scientific disciplines into meltdown.
This is a biologist’s equivalent of all your Christmases coming at once!
You see, once you’ve earned the prestigious title of extinct, it kinda stays with you—like…forever…
Your secrets die with you also, leaving the detectives with little more than a fossil record and painstaking speculation.
A Joyous Comeback For Science!
This apparent extinction fake-out was a cause for scientific celebration…
Why we hear you ask?
Well, it’s because these creatures are strongly linked to life’s progression from the oceans to the land.
The living coelacanth discovery represented significant potential for evolutionary revelations. Science heaven!
Let’s go swimming with a very rare yet not-so-missing link. The coelacanth…
Physical Features: Fish with Lungs?
Before we discuss its good-looks or otherwise, let’s get the pronunciation correct…
Coelacanth is pronounced “SEEL-uh-Kanth.”
Top points for those who got it right from the get-go – it’s a tough one.
Now that we got that all cleared up…
Lets dive in!
A Big Fish with a Big Mouth and a Little Brain
In anybody’s language, the coelacanth latimeria is a big fish…
When fully grown it can be more than 6 feet long, and weigh in at more than 200 pounds….
To put that in perspective, that’s longer and heavier than the average American human male!
DID YOU KNOW?
A coelacanth has a proportionately big mouth too. However, it has a unique feature called an intracranial joint.
Essentially, an intracranial joint is a hinged mouth. Its head can pivot upwards, allowing its mouth to open extra wide, presumably for eating large prey.
Coelacanth Brain
the coelacanth brain is minuscule…
Conversely, the coelacanth brain is minuscule. Most of their brain cavity is full of fat, only 1.5 percent of this space is brain. It seems a big brain has little to do with longevity.
A 12-foot saltwater crocodile has a brain the size of a walnut, yet has been around for over 240M years.
Given these facts alone, it would appear longevity is all about having a big mouth and a small brain.
Hmmm… definitely something to think about right?
Coelacanth Weird Bits
Most of the other fishes we are familiar with are actinopterygians. This means “ray-finned”. Salmon, mackerel and trout, for example, are “ray-finned”. Their pelvic fins are supported by spines.
Coelacanths are sarcopterygians or “lobe-finned” fishes. There are no spines or solid bones in their fins.
These lobe-finned fish have fins that are a fleshy protrusion. It is this feature that holds the evolutionary links, which we’ll discuss later…
Links to Evolution
Interestingly, the four fleshy paired fins move in an alternating pattern more like four-legged land living animals, such as a horse or dog.
Therein lies another hint to the sea-to-land evolutionary link.
If you want to know more about interesting Coelacanth features…
Watch the cool video below…
While these creatures are vertebrates, their spine is actually hollow and filled with fluid. Called a notochord, the spine is much the same as the early vertebrate lineage of millions of years from the past.
FUN FACT
Coelacanth is Greek for hollow spine, this is where it got its tricky name.
Electro-Sensory Perception?
Many fishes use an electric sensory receptor / rostral organ on their snouts to find prey and navigate.
This includes but is not limited to sharks, dolphins, countless fish species, and weirdos such as the Australian platypus.
The coelacanths too, use electroreception to find its dinner. However, where other fish have thousands upon thousands of sensory canals, they have only three paired sensory canals.
Other species send electronic messages to different parts of their bodies, such as the head. They send messages directly to the dorsal snout – their top lip, more or less.
Purpose
Researching scientists believe this is the first discovery of a low-resolution electro-detector designed specifically for catching prey.
It is also speculated that a coelacanth will use this snout mounted sensory rostral organ to avoid running into doors and falling down the stairs. Simple navigation stuff.
Nothing to Look at Here…Or is there?
Relative to some of the fish that live in its neighborhood, most coelacanths aren’t really that weird-looking. A little prehistoric, yes. But pretty ‘normal’ nonetheless.
These creatures have a grey/brown color with interesting pale blotches. Its scales are very thick, looking like medieval armor, but that’s not so strange…
It uses normal-looking fish gills to breathe, and most of its body parts look proportionate.
Not so common
Its eyes appear to be symmetrically placed on its head, not too big, or small, and it would appear to swim gracefully if a little lethargically.
Compared to the sunfish, or the barreleye and the angler fish, it’s really only its limb-like fins that stand out as odd.
In fact, it’s really a very attractive sea creature…
However, when we open these creatures, that is, dissect it, we find a superfluous lung inside its belly?
History, Distribution, and Breeding: How They Lived To Tell The Tale
When scientists discovered an obsolete lung inside the abdomen of coelacanths…
They concluded that millions of years ago the coelacanths likely used the lung to breathe.
They suggest that some of these creatures moved out into deep waters…
Triggering the change over time in the breathing mechanism.
The lung became superfluous in the new species and those with lungs that remained in the shallower depths…
Probably were wiped out with nearly all other life on earth, during the big extinction event over 65 million years ago.
Yes… the one that took out the dinosaurs.
So how are they still alive?
The Evolution Plot Thickens
It was the Sarcopterygians or lobe-finned critters, that took life out of the water to breathe air on land.
They’re known as tetrapods, Greek for 4 feet.
About 400M years in the past…
It was one of these tetrapods, that gave rise to all vertebrates, including the dinosaurs and, yes, human beings. Somewhat later of course.
It is understood that these creatures are ancestors of the tetrapods, which probably explains the lung and the lobed fins.
New Discovery
However…
More recent studies suggest that it is the lungfish, a close relative of coelacanths that is more closely related to the first land-dwelling tetrapods. The African coelacanth genome also provides insights into tetrapod evolution.
Lungfish, the oldest coelacanth, and tetrapods are all assumed to have diverged, or branched off on a separate evolutionary path about 390 million years in the past.
Science speculates with some authority…
That coelacanths are closely related to the tetrapod. It simply took a different path.
Distribution and Lifestyle of the Ancient Coelacanths
The coelacanth latimeria chalumnae is particularly rare…
The first coelacanth latimeria chalumnae was discovered in the Western Indian Ocean on the coast of South Africa in 1938.
60 years later, another type of its species called Latimeria menadoensis was discovered in Indonesia.
Analysis showed that the coelacanth latimeria chalumnae and latimeria menadoensis are closely related and likely share a common ancestor.
However, there are significant differences between the living species.
Where do They Live?
Modern coelacanths live mostly off the eastern coast of the African continent…
Locations include the waters off Kenya, Tanzania, Mozambique, South Africa, Madagascar, Indonesia, Comoros Islands (off the east coast of Africa) and the Indian ocean.
The Latimeria, or Indonesian coelacanth species is found off the coast of Manado Tua Island, Northern Sulawesi, Indonesia in the Celebes Sea.
Coelacanths can be found in water as deep as 2300 feet…
Live coelacanths can be found in deep sea in water depths of up to 2300 feet, that’s nearly half a mile!
However…
The regular haunt is more like 300 to 600 feet mark, feeding and living in the benthic zone. That is the ocean floor.
This is still very much deep sea territory, and relatively cold. It appears cold water is more suitable for its breathing, and their sensitive eyes are more suited for the dark…
In fact, they are rarely seen during full moons.
DID YOU KNOW?
At some point in time, coelacanths were thought to have become extinct, but live specimen were rediscovered in 1938 off the coast of South Africa
Relatively Little is Known About Love and Breeding of Coelacanths
It is understood that a Sulawesi coelacanth can live up to 60 years. However, it is believed they do not reach sexual maturity until age 20.
This would support the notion that they were never a prolific living species at any time in their considerably long evolutionary history.
Coelacanth Gestational Period
Once mature, the male will fertilize the eggs, which are retained inside the female. After a 13 month gestation period,fully formed live young are released into the water.
Mom can expect from 5 to 25 pups each time. The pups are completely independent and able to survive on their own from the moment they are born.
NOTE
To give you an idea of size, one pregnant mom was found to have 26 young pups inside her with each measuring over 12 inches long.
Daily Routine, Feeding, and Threats: A Night with a Coelacanth
These creatures are nocturnal…
It heads out to feed in the evenings.
During the day, however…
The coelacanth latimeria chalumnae aggregates in caves and large rock crevices doing not much at all.
It is often found residing in a regular place with up to a dozen coelacanth friends…
Scientists have observed that they’re pretty chill. There appears to be no fighting or territorial disputes.
In fact, they tend to keep to themselves…
If these creatures touch one another, they kind of retreat as if respecting the others personal space, or retreating to its own.
DID YOU KNOW?
Interestingly, other coelacanths are known to retreat when approached by large things such as research submersibles.
Scientists surmise that this flight behavior suggests caution. It may indeed be the prey of predators such as sharks.
A Casual Feed
Coelacanths head out to feed in the evenings. It’s not a predatory feeder, it’s more of an opportunist, drifting with the current and eating anything that comes into its path, swallowing it whole.
It swims lethargically as if it’s in no hurry at all. However, it is known to cover as much as 5 miles a night while feeding.
Menu items include other fish and cephalopods. Cephalopods include creatures such as octopus, squid, and nautilus, for example.
Metabolism of the Coelacanth
They have a very sluggish metabolism. This certainly has benefits in an ocean zone like the twilight zone, as finding food can be pretty tough.
It’s believed that its slow metabolism and ability to do without food for longer periods, may have saved it from extinction.
How so?
Food was tough to come by when most of the life on earth went extinct 66 million years ago.
Coelacanth as Prey
Every yin has a yang. While they may have survived Armageddon, it is slow and lazy – every day’s a holiday – disposition, may have its drawbacks.
Scientists and divers have observed shark bites on them. One would have to assume that some got it a lot worse than just a few scars. Plenty of other fish eating animals are also poised to do the same.
Major Threats
Like so much of the marine life in our oceans, the coelacanth’s greatest threat is from commercial fishing by-catch.
The oil fish trade was particularly destructive…
Because oil fish inhabit the same waters as the coelacanth, and feed at night, as coelacanth do. Many were just fish caught unintentionally.
Sold for Research
Before the ’80s these creatures were simply thrown back.
However, following the growth of scientific interest…
Fishermen began trading them with scientists.
To encourage fishermen to avoid catching them…
Incentives were offered to local fishermen in the form of more seaworthy boats.
This allowed them to fish beyond the habitat where coelacanths rest.
Unfortunately, over time the motors for the new boats fell into disrepair…
The fisherman simply returned to the original fishing grounds, putting further pressure on the population of coelacanth specimen.
New Conservation Methods
In 2014, a method of deep water release was devised for returning fish caught unintentionally like living coelacanths…
A hook and weight were connected to the fish that would release from the fish when it hit the ocean floor of the coelacanth’s resting habitat.
Unfortunately, the jury is still out as to whether the intervention was successful or otherwise. Data is not readily available.
Various countries have funded or provided habitat protection…
This includes broader habitat protections for many living fishes, including that of the coelacanth.
Interactions with Humans: Our Effect on Coelacanths
Having remained out of public view for literally millions of years, it’s now somewhat of a celebrity.
Owing to its location and habitat, these sea creatures are not so easy for the masses to access…
But still, there’s plenty of divers that want to swim with a living fossil.
How does that affect the coelacanth population?
Check out this cool video of divers finding a Coelacanth…
Unregulated fish tourism doesn’t seem to be an issue for these creatures…
The stresses of tourism has had significant impact on species such as the whale shark, and other easily accessed tropical reefs, and its inhabitants.
FUN FACT
Coelacanths are not harmful in any way to humans. In fact, they are considered a very gentle and peaceful creatures.
The Coelacanth for Human Consumption
…coelacanths can consider themselves very lucky that it evolved with a horrible flavor.
Given the way we humans ravage the ocean’s resources, coelacanths can consider themselves very lucky that it evolved with a horrible flavor.
It’s completely unsuitable for human consumption.
Its flesh contains a delicious cocktail of oil, urea and wax esters…
Its flesh contains a delicious cocktail of oil, urea and wax esters. While you might be able to polish your car with these bony fishes, eating them is out of the question.
If those wonderful ingredients weren’t enough, there’s a host of other nefarious compounds that will make diners sick.
Its scales ooze mucus, the flesh is slimy, and it smells disgusting.
Hungry yet? Wanna coelacanth BBQ?
Unfortunately, Coelacanths are Endangered Species
The International Union for Conservation of Nature (IUCN) has classified Latimeria chalumnae, the African (West Indian Ocean) Coelacanth, as critically endangered species.
It is estimated that there are only 500 left in the wild.
Latimeria menadoensis, the Indonesian coelacanth species, is listed by the same official body as vulnerable…
It is estimated that there is a much healthier population of around ten thousand individuals.
Nonetheless, considering the size of the ocean and the expanse of their habitat, ten thousand still seems like a precarious number.
Few in Numbers
Scientists suggest, that even in their heyday millions of years in the past, their species were not such prolific creatures.
It would seem a horrible twist of fate, that their species could survive over 300M years, including a major, almost complete extinction event, only to succumb to human carelessness.
Conclusion: Wrapping Up The Coelacanth
Surviving over 300 million years of evolutions, fickle twists, and a meteor-driven partial Armageddon…
It surely deserves some sort of fancy commendation.
Coelacanth fishes are true survivors.
Does it hold the secret to longevity?
Is a small brain, a low social profile, a big mouth, and a profoundly lazy disposition the meaning of life?
These creatures pose a pretty strong argument in the affirmative.
Or, is it a twist of fate and a bunch of dumb luck, that sees them cruising leisurely about the contemporary benthic zone?
These species have a pretty significant heritage and bloodline…
In fact, when you think about it, if evolution twisted a little differently, it may be their species paying taxes, driving cars and losing itself in its mobile phone.
A Different Path
At some point around 400M years in the past, the coelacanth diverged from their ancestors. They managed to stay in the ocean, and its ancestors became us.
It truly mind-blowing when you think about it.
Having survived all of this time and unimaginable chaos, it seems ridiculous that now its future hangs precariously in the balance.
Surviving global extinction events obviously requires some serious survival skills.
However, there are few, if any species that possess the capacity to survive humankind.
Can you see the irony here?
Having endured for millions of years, changing very little, if at all…
The fate of these creatures lies in the hands of the evolved ancestor it diverged from over 400M years ago.
Now that you’ve discovered how this supposedly extinct fish came back to life.
If you think that people you know might be intrigued by the Coelacanth’s rise from the dead
Feel free to share this content to let your friends discover this living fossil too!
- (Featured Image) Preserved Coelacanth from Numazu Deep blue-Aquarium Shizuoka Japan – by Kentaro Ohno さん – https://www.flickr.com/photos/inucara/ – https://www.flickr.com/photos/inucara/8442067878/, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=26348779
- Preserved Coelacanth from SAIAB exhibition in Makhanda Grahamstown – By A3 Baard – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=80591778
- Coelacantheformes Fossil From Natural History Museum of Bamberg – By Ghedoghedo – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=63980943
- Geographical Distribution of Coelacanth (4) – By Anaxibia – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7709497
- Preserved Juvenile Coelacanth SAIAB exhibition in Makhanda Grahamstow – By A3 Baard – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=80591779
