Tag Archives: giant tortoise

Drinking From The Giant Tortoise Pericardium

In preparation  for our Voyage of the Samba in the Galapagos Islands I’ve been reading the chapter of Darwin’s Voyage of the Beagle that describes his 31 days in the archipelago.

Darwin felt the reptiles of the Galapagos  gave the “most striking character to the zoology ” of the islands. He spends considerable time in his diary describing the creatures for whom the Spaniards named the islands. the giant tortoises.

Giant Tortoises

A Galapagos giant tortoise  can weight up to 600 pounds and live up to 150 years. A distinct species of tortoise developed on each separate island, adapting to differing environments.

On Charles Island (now Floreana) Darwin encountered the slowly

Lonesome George was the last survivor of the abingdonii subspecies, which became extinct with his death on 24th June, 2012.

lumbering (4 miles per day) tortoises when they traveled to the central highlands to fill themselves with water.  Prior to encountering humans the tortoises had  had no natural predators and both the natives and the crews of whaling ships feasted on their easily obtained meat.

“the staple article of animal food is supplied by the tortoises. Their numbers have of course been greatly reduced in this island, but the people yet count on two days’ hunting giving them food for the rest of the week. It is said that formerly single vessels have taken away as many as seven hundred, and that the ship’s company of a frigate some years since brought down in one day two hundred tortoises to the beach.”

Natives savored both tortoise flesh and tortoise oil:

The flesh of this animal is largely employed, both fresh and salted; and a beautifully clear oil is prepared from the fat. When a tortoise is caught, the man makes a slit in the skin near its tail, so as to see inside its body, whether the fat under the dorsal plate is thick. If it is not, the animal is liberated and it is said to recover soon from this strange operation. In order to secure the tortoise, it is not sufficient to turn them”

Darwin also partook of tortoise:

“While staying in this upper region, we lived entirely upon tortoise-meat: the breast-plate roasted (as the Gauchos do carne con cuero), with the flesh on it, is very good; and the young tortoises make excellent soup; but otherwise the meat to my taste is indifferent.”

I’m pretty certain the passengers on the Samba will not be consuming any Giant tortoise meat this August but we will definitely encounter some of the surviving species on special farms and I will be listening for bellowing males:

During the breeding season, when the male and female are together, the male utters a hoarse roar or bellowing, which, it is said, can be heard at the distance of more than a hundred yards. The female never uses her voice, and the male only at these times; so that when the people hear this noise, they know that the two are together”

Perhaps I will be allowed to startle or ride a tortoise in the manner of Darwin:

“The inhabitants believe that these animals are absolutely deaf; certainly they do not overhear a person walking close behind them. I was always amused when overtaking one of these great monsters, as it was quietly pacing along, to see how suddenly, the instant I passed, it would draw in its head and legs, and uttering a deep hiss fall to the ground with a heavy sound, as if struck dead. I frequently got on their backs, and then giving a few raps on the hinder part of their shells, they would rise up and walk away; — but I found it very difficult to keep my balance.

Drinking FromThe Pericardium Of The Giant Tortoise

Finally, as this is a cardiology-oriented site I must take note of the following peculiar Darwinian observation:

“I believe it is well ascertained, that the bladder of the frog acts as a reservoir for the moisture necessary to its existence: such seems to be the case with the tortoise. For some time after a visit to the springs, their urinary bladders are distended with fluid, which is said gradually to decrease in volume, and to become less pure. The inhabitants, when walking in the lower district, and overcome with thirst, often take advantage of this circumstance, and drink the contents of the bladder if full: in one I saw killed, the fluid was quite limpid, and had only a very slightly bitter taste. The inhabitants, however, always first drink the water in the pericardium, which is described as being best.”

When I came across this description I was flabbergasted. Not at the inhabitants drinking tortoise urine (for indeed the tortoise does use his giant bladder as a water reservoir during times of drought) but at the Galapagoans drinking pericardial effusions.

The Pericardium

The pericardium is the sac around the heart. I am very familiar with the pericardium in humans as I look at it on every one of the  many echocardiograms I read.  Normally, it has only a very tiny bit of fluid in it, enough to lubricate the heart as it contracts and relaxes.

Thus, in a normal giant tortoise one would not expect more than an ounce of liquid in the pericardium-hardly worth butchering an ancient kind beast.

In the video below one can see a small to moderate sized pericardial effusion (the black crescent on the left of the heart) which corresponds to about 90 ml or 3 ounces.

I asked Jim Scharff, a cardiothoracic surgeon,who slices open the pericardium of humans on a daily basis what he typically encounters when the sac is opened. The question I texted him was:

“When you open the pericardium of someone without pericardial disease or effusion how much fluid do you typically encounter and what does it taste and look like?”

He responded  “Usually 15-20 mL of serous looking fluid. I have no idea what it tastes like but it does not have any odor.”

Serous means ” typically pale yellow and transparent” and limpid, Darwin’s term, means transparent and clear.

Some diseases cause inflammation of the pericardium (pericarditis) and with this fluid (pericardial effusion) can build up in the pericardial sac. Large pericardial effusions compress the heart, impeding blood from entering it, and can cause shock and death (tamponade).

Pericardial effusions due to inflammation typically are not limpid as they contain blood cells and protein from the inflammation of the pericardium.

Ultrasonic Explorations

If the inhabitants were sometimes encountering significant amounts of tasty, yet limpid fluid in the pericardial sac of the giant tortoises was this normal or did it indicate the turtles had pericardial disease?

I was unable to find any indication that giant tortoises suffer unduly from pericardial disease but I did encounter one study which utilized ultrasound to document a pericardial effusion in an 80 year old spur-thighed tortoise which was suffering from pneumonia.

Consequently, I’m looking into taking a portable ultrasound device to take with me to the Galapagos to examine the hearts of the giant tortoises and answer once and for all the mystery of the giant tortoise pericardial fluid.

Testudinally Yours,





We Are Soon Bound For The Galapagos Islands In Search Of Darwin, The Giant Tortoise, and Dangerous Ideas

This is not the Samba. It is Her (or His) Majesty’s Ship, The Beagle

In August, the skeptical cardiologist and his eternal fiancée (and our friends Dave and Barb) will be visiting the Galapagos Islands on the 78 foot yacht, the Samba.

I’ve long wanted to visit this archipelago with its fascinating geographic and biologic features and its connection with Charles Darwin.

Darwin, born in 1809, was the son of a successful Shropshire physician and financier. By the age of 8, he writes in his Autobiography, “my taste for natural history, and more especially for collecting, was well developed. I tried to make out the names of plants and collected all sorts of things, shells, seals, franks, coins, and minerals. The passion for collecting, which leads a man to be a systematic naturalist, a virtuoso or a miser, was very strong in me, and was clearly innate, as none of my sisters or brother ever had this taste.”

After 2 years of studying medicine at Edinburgh University, Darwin writes, “my father perceived or he heard from my sisters, that I did not like the thought of being a physician, so he proposed that I should become a clergyman.”

In the course of obtaining the undergraduate degree needed to join the ministry, Darwin  developed a passionate interest in natural history, and two books in particular, instilled in him the desire to be a scientist:

During my last year at Cambridge I read with care and profound interest Humboldt’s Personal Narrative. This work and Sir J. Herschel’s Introduction to the Study of Natural Philosophy stirred up in me a burning zeal to add even the most humble contribution to the noble structure of Natural Science.

After graduating Cambridge, Darwin, being recognized as “a young man of promising ability, extremely fond of geology, and indeed all branches of natural history,” was offered a position on a ship destined for a 5 year voyage around the world. This would profoundly influence his life and mankind’s vision of its origin.

The Voyage of the Beagle

In preparation for my visit to the Galapagos and our voyage on the Samba, I have been reading (from a free digital download) Darwin’s account of that historic voyage:  “The Voyage of the Beagle” (originally entitled “Journal of researches into the natural history and geology of the countries visited during the voyage of HMS Beagle round the world,” published in 1839), which Darwin introduces thusly:

Captain Robert Fitzroy..As Darwin gathered the threads of what would later become his ‘dangerous idea’, FitzRoy guided them safely through treacherous waters, measured tides, studied weather systems, surveyed new territory, corrected existing charts and, for the first time, established a series of reference points around the globe that others would calibrate their instruments by. courtesy RNLIWhen Darwin published On the Origin of Species, FitzRoy admitted that it caused him the ‘acutist pain’. As a passionate creationist, he was wracked with guilt at unwittingly playing a part in its construction. This, along with mounting debts and failing health, soon locked him into a losing battle with depression. Just weeks before his 60th birthday, Vice Admiral FitzRoy  took his life.

HIS MAJESTY’S ship, Beagle, under the command of Captain FitzRoy, was commissioned in July, 1831, for the purpose of surveying the southern parts of America, and afterwards of circumnavigating the world. In consequence of Captain FitzRoy having expressed a desire that some scientific person should be on board, and having offered to give up part of his own accommodations, I volunteered my services; and through the kindness of the hydrographer, Captain Beaufort, my appointment received the sanction of the Admiralty.

The Beagle was only 12 feet longer than the Samba motored sailing boat that we, along with 12 other adventurous passengers, 5 crew men and a guide, have selected for our Galapagos tour. However, Darwin’s vessel carried, in addition to Fitzroy and Darwin, 71 other passengers (whose names you can ponder here).

The Beagle Sets Sail

On the 27th of December, 1831, the Beagle sailed from Devonport with the object of completing:

“the survey of Patagonia and Tierra del Fuego, commenced under Captain King in 1826 to 1830, — to survey the shores of Chile, Peru, and of some islands in the Pacific — and to carry a chain of chronometrical measurements round the World. ”

The Beagle spent four years surveying the east coast of South American and didn’t reach the Galapagos until the fall of 1835, nearly 4 years after its launch.  Darwin describes the islands as follows:

“SEPTEMBER 15th. — This archipelago consists of ten principal islands, of which five exceed the others in size. They are situated under the Equator, and between five and six hundred miles westward of the coast of America. They are all formed of volcanic rocks; a few fragments of granite curiously glazed and altered by the heat, can hardly be considered as an exception.

Darwin disembarked on San Cristóbal (September 17-22), Floreana (Charles)(September 24-27), Isabela (Albemarle)(September 29-October 2) and Santiago (James)(October 8-17).

FitzRoy and his officers developed updated charts of the archipelago, while Darwin collected geological and biological specimens on the islands.

(Our voyage below, visits the northwestern Galapagos, islands crossing paths with Darwin when we land in Isabella and Floreana









The Giant Tortoises of the Galapagos Islands

Darwin learned much on his voyage, not just about the geology and biology of the islands, but also about himself and the importance of reason and observation:

I discovered, though unconsciously and insensibly, that the pleasure of observing and reasoning was a much higher one than that of skill and sport. The primeval instincts of the barbarian slowly yielded to the acquired tastes of the civilized man.

Apparently his acutely observant father identified these changes in thinking just by looking at Charles:

That my mind became developed through my pursuits during the voyage, is rendered probable by a remark made by my father, who was the most acute observer whom I ever saw, of a sceptical disposition, and far from being a believer in phrenology; for on first seeing me after the voyage, he turned round to my sisters and exclaimed, “Why, the shape of his head is quite altered.”

So, dear friends and patients, pay close attention to the shape of my head upon my return from the Voyage of the Samba. You might assume the large occipital protuberance is a result of a nasty fall from the top of a giant tortoise when, in fact, it is the outward representation of all the brilliant observations and dangerous ideas I have acquired on my trip.

Galapaghostly Yours,


N.B. Of the many observations that Darwin made while he was on the Galapagos Islands, I found his comments on the pericardium of the giant tortoises the most intriguing. My next post on Darwin and the Galapagos will explore in detail this fascinating cardiologic observation.