World Oceans Day: A Bibliographic Exploration of Ocean Giants

This post is the fourth in our series leading up to the celebration of World Oceans Day on June 8. This series explores publications that represent important milestones in the progress of marine bioscience research and ocean exploration.

When you think of the largest creatures in the ocean, what do you picture?  You might be surprised about which creatures are largest, and about some of their fascinating histories and habits!  A recent article in the journal PeerJ documents the body length of some of the longest animals in the ocean, and in preparation for World Oceans Day on June 8, we’re diving deeper into the top ten listed in that article.

One of the First Scientists to Record a Plethora of Species: Linnaeus

Carl von Linnaeus (also known as Carl von Linné) was the first person to record several of the species in this top ten list, which he did in his book, Systema Naturae.  The tenth version of this book, published in 1758, is considered his authoritative taxonomical text, and scientists use the year 1758 to refer to Linnaeus’ taxa from this book (an important change Linnaeus made in the tenth version was to move whales to the mammal class rather than the fishes class).  Linnaeus was a Swedish zoologist and botanist, and also practiced as a physician.  He was born in Sweden in 1707, traveled to the Netherlands in his thirties to write Systema Naturae, returned to Sweden, and continued traveling throughout his life to further classify biological organisms.  He is known for creating the forerunner to the modern binomial nomenclature system, which was referred to as the Linnaean taxonomy.  He died in 1778 after having the opportunity to engage in philosophical conversations with other famous philosophers, teach medicine and botany, and continue to add to his taxonomy.

A Dive into Ten Ocean Giants, from Longest to Smallest (though still very long!):

1. The lion’s mane jellyfish (Medusa capillata, also known as Cyanea capillata) is the largest species of jellyfish, and possibly the longest animal in the world, with tentacles that make this jellyfish 120 feet in length (though some estimates suggest that the bootlace worm, found in muddy and sandy shores and tide pools around the North Sea, is longer – possibly more than 170 feet long. However, since ribbon worms can stretch much more than their actual growth rate, these estimates are controversial).  It lives in cold waters, such as the Arctic, northern Atlantic, and Pacific Oceans, as well as the English channel, Irish Sea, North Sea, Scandanavian waters and sometimes the Baltic Sea.  Its tentacles are long, thin and hair-like, which is why it is referred to as a “lion’s mane”.  The bell, or umbrella, which comprises the top part of the jellyfish, can grow up to a diameter of 78.74 inches.  The hair-like tentacles emerge from the margin of the bell, in eight groups of 70 to 150 (or more) hollow tentacles, while more tentacles emerge from the bell’s subumbrella.  This jellyfish is generally a vivid yellow, orange or red color.  It feeds on zooplankton, and small fish, among other smaller creatures, and its predators include larger fish, seabirds, other jellyfish, and sea turtles.  The lion’s mane jellyfish was first scientifically documented (as Medusa capillata) by Carl von Linnaeus in 1758, in his Systema Naturae, which you can read here:

Fun facts: The lion’s mane jellyfish was featured in Sir Arthur Conan Doyle’s short story “The Adventure of the Lion’s Mane”, in which the “murderer” turns out to be the jellyfish—although in real life, the lion’s mane jellyfish is not capable of killing humans, only causing a very painful sting that can result in blisters, cramps and affected heart rate and respiratory function.

2. The blue whale (Balaenoptera musculus) was first described by Linnaeus in 1758 in Systema Naturae, and was thought to be the largest animal on the planet, though if measuring by length, it is out-shadowed by the lion’s mane jellyfish.  The blue whale is 108.27 feet long, and can weigh as much as 40 African elephants.  This species is also considered to have one of the fastest swimming speeds, at up to 30 miles per hour.  They live in all of the world’s oceans.  These amazing mammals eat up to seven tons of krill per day, by stretching their throats to open their mouths wider, and then gulping a large amount of water filled with krill.  They then use their tongues to expel the water out again through baleen plates, which capture the krill and prevent them from escaping.  The blue whale has the deepest voice of any living creature (at a frequency below humans hearing), and their voices can be heard by other blue whales for thousands of miles underwater.  Scientists have theorized that these far-reaching vocalizations help the whales map their locations across oceans.  Very little is known about their mating patterns.  This species can live as long as a human: 80 to 90 years.  You can read Linnaeus’ account of the blue whale here:

Fun facts: Blue whales can dive underwater for up to 30 minutes.  A whale’s age can be determined by counting layers of waxy earplugs that develop in the whales over time (like counting tree rings).

3. The sperm whale (Physeter macrocephalus) was also first described by Linnaeus in 1758.  At a length of 78.74 feet, it is the third-longest animal listed in the PeerJ article.  Among whales with teeth, the sperm whale is the largest, and also has the largest brain of any animal on the planet.  The sperm whale’s head takes up a third of its body length, and there is a specialized feature in the head that helps this whale dive deeper or rise to the surface of the water: the spermaceti organ.  This refers to a large cavity in the whale’s head filled with a waxy substance called spermaceti oil, which can be cooled (to shrink and increase density, allowing the whale to dive deeper), or heated (to expand and decrease density, allowing the whale to rise to the surface of the water).  Scientists posit that the spermaceti oil is cooled by water intake through the whale’s blowhole.  However, scientists are still trying to figure out the purpose of the spermaceti organ, and some believe it might absorb unnecessary nitrogen during dives, or help make the whale’s communicative clicking sounds resonate more loudly.  While the head of this species is extremely large, its lower, toothy jaw is very narrow and short in comparison.  The sperm whale eats giant squid, which live in deeper parts of the ocean, thus the sperm whale can dive up to one mile deep and stay under water for up to 90 minutes.  Sperm whales can live up to 70 years, and while they are close to the top of the food chain, they can be attacked by killer whales.  You can read Linnaeus’ account of the sperm whale, which is on the same page as that of the blue whale, here:

Fun facts: In Herman Melville’s novel, Moby Dick, Captain Ahab was fighting a sperm whale.  The skin of a sperm whale is dark brown or blue-black, and is said to feel like the pit of a plum.  Sperm whales produce ambergris, which was once used in perfume making.  Scientists count the layers of dentinal growth on sections of sperm whale teeth to determine age.

4.  The whale shark (Rhincodon typus), with a length of 61.68 feet, was first described by Sir Andrew Smith in 1828.  Smith published his findings on the whale shark in 1829 in Zoological Journal.  Smith (born 1797, died 1872) is considered a major influence in South African zoology.  He was born in Scotland, got his M.D., and practiced as a surgeon, ethnologist and zoologist.  He traveled with the Army Medical Services to South Africa and studied biological specimens there, as well as studying people native to the region.  He illustrated many specimens in Illustrations of the Zoology of South Africa (1838-1850), which you can read here:  Smith first noted the whale shark in 1828 after one was harpooned in South Africa while he was stationed there.  While it is similar in size to a whale, the whale shark is actually the largest fish in the world.  It has a wide, flat head and mouth, and dark, grey-blue skin with a beautiful pattern of pale yellow dots all over the top and sides of its body.  This shark has five large gills which contain cartilage that acts as a sieve.  Whale sharks generally eat smaller fish, and suck their prey into their large mouths and then swallow the unfortunates.  It is considered a filter feeder like the basking shark (to be mentioned later), but is much more active in its feeding than the basking shark, pumping water into its mouth sometimes in a stationary position, unlike the basking shark, which needs to swim in order to allow water into its mouth.  The whale shark lives in tropical and warm seas around the globe.  This species is not generally harmful to humans.  Unfortunately, people continue to hunt these sharks for human consumption, using parts of the shark in health supplements and shark fin soup.  Read Sir Andrew Smith’s description of the whale shark in The Zoological Journal here:

Fun facts: The whale shark’s mouth has up to 300 very small teeth, the function of which are unknown.  While scientists do not have a great understanding about how whale sharks reproduce, a pregnant female was captured and inside of her were 300 fetuses.  Known as gentle giants, sometimes humans can swim alongside, or catch a ride with, the whale shark.

5.  The basking shark (originally called Squalus maximus, now known as Cetorhinus maximus), at a length of 40.25 feet, was first described by Johan Ernst Gunnerus in 1765.  Gunnerus was born in Norway, and practiced as a professor of theology and a bishop, as well as a botanist.  He helped found what became the Royal Norwegian Society of Science and Letters [Det Kongelige Norske Videnskabers Selskab, based in Trondheim, Norway], and published his findings on the basking shark in the Society’s journal in 1765.  This original publication has yet to be digitized by BHL, but its citation is as follows: Gunnerus, J.E. (1765). Brugden (Squalus maximus), Beskrvenen ved J. E. Gunnerus. Det Trondhiemske Selskabs Skerifter (v. 3). pp. 33-49.  Gunnerus communicated with Carl von Linnaeus (mentioned above, and also known as Carl von Linné) about some of his biological findings.  Linnaeus, in turn, helped found, and communicated with, The Royal Swedish Academy of Sciences [Kungliga Svenska Vetenskapsakademien], which published a journal in 1770 citing Gunnerus’ discovery of the basking shark, which you can read here:  Gunnerus was elected as a foreign member to the Royal Swedish Academy of Sciences in 1766.  As mentioned in the whale shark entry above, the basking shark is a less active filter feeder, and must swim over the plankton it wants to consume in order to get them into its mouth.  While basking sharks have no teeth, they have a filter that allows water to flow out of their mouths while trapping the plankton.  This species is the second-largest fish in the world.  Only one pregnant female has been caught so far, and she gave birth to six live sharks.  This shark lives around the world in boreal and temperate waters.  The basking shark can live to at least 50 years old.  They have been hunted for similar reasons to the whale shark, but are protected in British waters.

Fun facts: Basking sharks can migrate for up to 5,592 miles, and when they are not migrating or following the plankton in coastal waters, they spend most of their time in the deep ocean.  During vertical and geographical migrations, basking sharks remain in groups of the same sex and age, which suggests an interesting pattern of segregation within the species.

6.  The giant squid (Architeuthis dux), measuring 39.37 feet long, was first described by Japetus Steenstrup in 1857.  Scientists refer to the first mention of the giant squid by Steenstrup as occurring both in 1857, when Steenstrup published his findings in a paper, and in 1860, when three illustrative plates were published by Pieter Harting describing Architeuthis dux.  One year later, in 1861, Harting published a text on Architeuthis dux, along with the plates, which you can read here:, and the mention of Architeuthis dux in the description of the illustrative plates begins here (Fig. 1. A.):  Steenstrup (born 1813, died 1897) was a Danish professor of zoology, and also studied biology.  Like Gunnerus, Steenstrup was also elected a foreign member of the Royal Swedish Academy of Sciences, in 1857.  Pieter Harting (born 1812, died 1885) taught medicine and zoology, and studied microscopy and botany, among other things.  The giant squid eats deep-sea fish and other squid by using serrated rings on its tentacles that suck onto the prey and bring the prey toward its beak, where a toothy tongue called a radula shreds the prey.  The squid has a mantle, eight arms, two tentacles longer than the arms, and hundreds of suction cups inside the tentacles.  This species has a complex brain and nervous system, and is found in oceans all over the world.  Scientists do not yet know how deep they inhabit the ocean, but some estimate that the giant squid can reside or feed at up to 900 meters deep.  Many specimens of giant squid which you see in museums were found washed ashore or in the stomachs of dead sperm whales, which regularly feed on them.  Scientists track sperm whales in order to study giant squid since the whales are so adept at locating and hunting the squid.

Fun facts: The giant squid has the largest eyes of any animal on earth, excepting the colossal squid, and the only creature known to have larger eyes is the extinct ichthyosaur.  The original edition of Twenty Thousand Leagues Under the Sea, a novel by Jules Verne, has an illustration of a man entangled in the tentacles of a giant squid.  The giant squid has been represented historically as the kraken.

7.  The giant octopus (Enteroctopus dofleini), with a radial spread of 32.15 feet, is the largest among a group of octopuses referred to as the “giant octopus”.  The first scientific description of this particular giant octopus is by Gerhard Wülker, in 1910, where he refers to it by a synonymous name, “Polypus dofleini”.  You can read Wülker’s original description of “Polypus dofleini” here:  Wülker (born 1885, died 1930) was a German zoologist who is famous for being the first to identify the giant octopus.  E. dofleini is found in the Pacific Ocean (and is thus known as the giant Pacific octopus), and can be found as deep as 6,600 feet below the ocean’s surface.  This species lives longer than other octopuses, with a lifespan of up to 5 years.  Like all octopuses, E. dofleini has a head, eight arms with suckers on each, and papillae (hooks) lining the suckers to increase the octopus’ ability to hold onto things, such as prey.  Prey include lobsters, fish, scallops, and shrimp, among other creatures.  Once prey is captured, either by using arms singularly or all together, it is brought up to the beak at the mouth and then torn apart by a toothy tongue called a radula.  E. dofleini has distinctive longitudinal folds on its body.  These octopuses follow a pattern of mating and reproducing once, and then dying, which is referred to as “semelparity”.  After reproducing, the giant Pacific octopus will enter a seemingly gruesome phase leading up to death called “senescence”: the octopuses will eat little, their skin will retract unpleasantly, white lesions appear on the body, and activity becomes clumsy until death ensues by starvation or being preyed upon.

Fun facts: The giant Pacific octopus can lay up to 400,000 eggs, which are cared for by the female members of the species; the female stops eating to do this, and dies soon after the eggs hatch.  E. dofleini sometimes eats sharks, such as the spiny dogfish (Squalus acanthias), which can be up to four feet long.

8.  The giant oarfish (Regalecus glesne), which is 26.25 feet long, was described by Peter Ascanius in 1772.  Ascanius (born 1723, died 1803) was a Norwegian scientist who taught zoology and minerology in Copenhagen.  He also practiced as a biologist, and was instructed by Carl von Linnaeus.  Like other scientists in this post, Ascanius was elected as a foreign member to a society dedicated to improving knowledge in scientific fields: in 1755 he was elected a foreign member of the Royal Society [in London], where he was considered a Fellow.  The giant oarfish is known as the “king of herrings”, and lives in oceans around the world.  Its body is shaped like a ribbon and it has a dorsal fin along its back that becomes vertically long right above its head, giving it the appearance of a rooster’s cockscomb.  This species has two pelvic fins comprised of only one ray; the fins are long and resemble oars.  There is a membrane at the tip of each pelvic fin that some scientists believe is used for tasting things.  Without teeth, the giant oarfish consumes krill by gulping water and then expelling it, trapping the krill in the gullet by means of a series of long spines.  Ascanius first wrote about the giant oarfish in 1772 in his work, Icones Rerum Naturalium, which is in the process of being digitized for BHL.  You can read the next earliest mention of the giant oarfish at the Biodiversity Heritage Library here, in Volume 2 of Monsieur le comte de La Cepède’s text, Histoire Naturelle des Poissons:  La Cepède, also known as Bernard Germain Étienne de La Ville sur Illon (born 1756, died 1825), was well-known for his contributions to the abovementioned work, Histoire Naturelle, written along with Georges Louis Leclerc, comte de Buffon.  La Cepède was a French naturalist and freemason.  Like other scientists on this list, La Cepède was elected as a Fellow of the Royal Society [London], and as a foreign member of the Royal Swedish Academy of Sciences, as well as a member of the Institute of France [L’Institut national de France].

Fun facts: The giant oarfish has no scales—instead, its body is covered in wart-like bumps called “tubercles”.  Adult members of this species sometimes kill themselves by swimming onto beaches.  The giant oarfish can self-amputate a part of the posterior end of its body, and apparently does this several times during its lifetime, as the amputated area repeatedly heals over into a stump.

9. The great white shark (Squalus carcharias, also known as Carcharodon carcharias), at 22.96 feet long, was first described by Linnaeus in his Systema Naturae in 1758 under the name Squalus carcharias.  The great white shark lives in most all oceans around the world, and can appear in coastal waters.  This species of shark is infamous for having the largest number of unprovoked attacks on humans.  However, the great white shark does not intentionally feed on humans.  Shark prey includes seals, dolphins, whales, sea lions, fish, seabirds, and other smaller creatures.  While they would appear to be at the top of the food chain, great white sharks can rarely be attacked, and killed, by groups of orca whales.  Scientists know very little about their mating behavior, but female sharks give birth to live young.  Great whites can swim up to 25 miles per hour in pursuit of prey, and launch themselves into the air from the water.  These sharks use smell, sound location and electroreception to spot prey from great distances.  The great white shark, unlike the majority of other fish, can maintain a higher body temperature than that of the surrounding water by means of a heat exchange system in their blood vessels.  These sharks can live up to 50 years.  Read Linnaeus’ account of Squalus carcharias here:

Fun facts: The oldest fossils of the great white shark are 16 million years old.  It is believed that the great white shark does not intentionally seek to attack humans, but is merely engaging in “test bites”, which it also performs on other unfamiliar objects in order to identify those objects.  The great white shark was featured in Peter Benchley’s novel, Jaws, as well as Steven Spielberg’s film adaptation of the same.

10.  The giant manta ray (Manta birostris, also known as Raja birostris) has a disc width of 22.96 feet, is the largest ray in the world, and can weigh up to two tons.  This creature was first described by Johann Julius Walbaum in 1792.  Walbaum (born 1724, died 1799), was a German physician.  He was also a naturalist and taxonomist, and the first to record many new-to-science species.  He referred to the giant manta ray as Raja birostris in his original description of the creature, though the giant manta ray is now known as Manta birostris.  This species inhabits tropical and temperate waters around the globe, and eats zooplankton like shrimp and krill.  The giant manta ray has triangle-shaped pectoral wings on either side of its body, and lobe-shaped fins towards the front of its body, extending from either side of the head.  These fins can aid in pushing water into the mouth to catch prey.  There are 18 rows of teeth in the lower jaw of its large, rectangular mouth.  Their skin is black, blue or brown, with a white underside.  Scientists look at unique patterns of markings and scars to identify individual rays.  The giant manta ray can live up to 20 years.  Read Walbaum’s description of Raja birostris here:

Fun facts: The giant manta ray can eat up to 13% of its body weight in food each week.  Sometimes the ray will remain still near a coral reef while other fish eat off pieces of loose skin and parasites, which cleans the ray and provides food for the fish.  The giant manta ray can leap out of the water, possibly as part of a mating ritual, and their offspring are called “pups”.

More World Oceans Day Resources

  • Follow us on Twitter, Facebook, and this blog all this week as we explore marine biodiversity and awesome related publications in BHL.
  • Check out some monumental publications in historic and present-day marine bioscience research in our BHL collection.
  • Browse a selection of marine biodiversity illustrations in Flickr and Pinterst
 Some Key References:
Brightwell, C. L. (1858). A life of Linnaeus. London: J. Van Voorst.
(n.d.). Encyclopedia of Life (EOL).  Retrieved from
(n.d.). Invertebrates of the Salish Sea.  Retrieved from
(n.d.) The Linnaean Correspondence.  Retrieved from
(n.d.). World Register of Marine Species (WORMS).  Retrieved from
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Laurel Byrnes is a Virtual Marketing Volunteer for the Biodiversity Heritage Library at Smithsonian Libraries.