[HN Gopher] Stanford researchers report first recording of a blu...
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Stanford researchers report first recording of a blue whale's heart
rate (2019)
Author : eatonphil
Score : 33 points
Date : 2026-03-13 19:15 UTC (3 hours ago)
(HTM) web link (news.stanford.edu)
(TXT) w3m dump (news.stanford.edu)
| PaulHoule wrote:
| Note they put a Holter monitor on it
|
| https://www.pnas.org/doi/10.1073/pnas.1914273116
|
| to get an ECG which is one of several strategies they could use.
| (e.g. lately I've been interested in Heart Rate Variability which
| has gotten me looking at reading heart rate with cameras, radars,
| pressure gauges, ultrasound, etc.)
| navane wrote:
| 30 BPM at the surface, 4 bpm while diving.
| flopsamjetsam wrote:
| "Analysis of the data suggests that a blue whale's heart is
| already working at its limit, which may explain why blue whales
| have never evolved to be bigger."
|
| Incredible to think of the volume of all the blood it's pumping
| around.
| tmoravec wrote:
| I don't understand how that would limit evolution. Bigger
| bodies can evolve together with bigger hearts, as already
| witnessed with the very whales being researched.
| JumpCrisscross wrote:
| > _don 't understand how that would limit evolution_
|
| Cardiac tissue is a surface. Blood is a volume. I think
| they're saying blue whale hearts are near the largest
| current biology can evolve. Which is interesting because it
| suggests if we could _e.g._ engineer whales with carbon-
| fiber hearts or whatever, they'd evolve to grow even
| bigger.
| observationist wrote:
| Blackheart the whale, lurking the oceans, ever devouring
| and growing. I think you've got a good Lovecraft/Pirates
| of the Carribean/Black Mirror mashup premise here.
| observationist wrote:
| The volume of blood that needs to be pumped increases
| exponentially cubically with size, meaning the cells have
| to do more work, or there have to be more of them. The size
| of the heart has to match the volume of blood being pumped
| - if they evolved to be larger, the heart might have to be
| so big that it creates pathology in other areas, or has to
| pump so hard it damages tissue, or creates forces so great
| that veins or arteries collapse or burst.
|
| It's probably not as dramatic an issue as that. It could
| also be sensory - past a certain size, in order to be
| sensitive enough to detect damage and deal with normal
| conditions, it would have to be irritated all the time, or
| numb to potential hazards.
|
| There are all sorts of second and third order consequences
| limiting how various vital systems can interplay, so more
| than likely, it's a combination of a whole bunch of things
| that subtly limit the overall size to where it's at, and
| any further increase degrades its abilities to survive.
|
| They're just so huge. Their brains are 4 times larger than
| a human's brain, but we share a whole lot of structure,
| from the cellular level to the macro, with two lobes, some
| shared sulcal features (same folding pattern) which
| indicates that we likely share enough connectomic structure
| for the ways in which our brains operate to produce similar
| conscious experiences. Someday, in the distant future, we
| should be able to use BCI to feel exactly what it's like to
| be a blue whale (and vice versa.)
|
| Their brains have similar cortical structure, but even
| though the brains are about 7 times larger, their cortical
| surface area is only 2-3 times that of a human. It really
| puts into context how bizarrely massive our brains are for
| our relatively tiny size.
|
| For contrast, titanosaur hearts would have been around 500
| lbs and up to 6 feet in diameter, and their brains were
| about the size of a big walnut. These land animals were up
| to 40m long and 100 tons.
|
| Anyway - physics of tissue and frailties of being made of
| meat are what keep the whales from getting much bigger.
| frotaur wrote:
| Nitpick, but the volume increases cubically (it scales
| with volume), not exponentially.
| observationist wrote:
| Thank you, I'll correct that. I was thinking inverse
| square law, then instead of asking an AI like a good
| nerd, I just winged it.
| kadoban wrote:
| > Bigger bodies can evolve together with bigger hearts, as
| already witnessed with the very whales being researched.
|
| Hm? Aren't blue whales the biggest animals to ever have
| lived that we know of?
| steve_adams_86 wrote:
| These are peak free diver goals. Though I'm sure I'd be
| guaranteed to black out at 4bpm, haha. Incredible.
| krunck wrote:
| A Whale's tachycardia is my bradycardia. Huh.
| bob1029 wrote:
| There are documented cases of perfectly healthy humans with
| resting heart rates under 30bpm.
|
| https://www.guinnessworldrecords.com/world-records/lowest-he...
| raldi wrote:
| Anyone got a direct link to or time index of the recording? I
| skipped around the video on the linked page but it was all music.
| nsbk wrote:
| I watched the whole video and there is no heartbeat sound,
| which is what I was expecting as well. I think that they
| recorded the signal, not the sound that the heart makes when
| pumping blood.
| arunc wrote:
| > Looking at the big picture, the researchers think the whale's
| heart is performing near its limits. This may help explain why no
| animal has ever been larger than a blue whale - because the
| energy needs of a larger body would outpace what the heart can
| sustain.
|
| Fascinating to learn such details!
| mr_mitm wrote:
| Could an animal have several hearts?
| djtriptych wrote:
| yes. I know octopuses and squids have three hearts. Just
| looked it up and it seems no mammal has more than one heart.
| joecool1029 wrote:
| I do wonder if those animals have things like valves in
| their veins, as I understand it if the circulatory system
| wasn't as complex as it is, heart would have to pump a lot
| harder to move the volume it does. This isn't an area I
| know much of anything about, I just know veins have valves
| and can expand and contract to different stimuli much as a
| heart can... so even though mammals have one heart it's not
| like the rest of the system is a static not helping to pump
| blood.
| trhway wrote:
| and the highest heart rate belongs to the smallest mammal
|
| https://en.wikipedia.org/wiki/Etruscan_shrew
|
| "The Etruscan shrew has a very fast heart beating rate, up to
| 1511 beats/min (25 beats/s) and a relatively large heart muscle
| mass, 1.2% of body weight."
|
| (to illustrate - machine guns typically do 600-900 rounds/min)
|
| I wonder whose muscle fiber is stronger per unit mass - the
| whale's or the shrew's...
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