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The Biggest, the Oldest, and the Baddest

A tour of the Earth's biggest, oldest, and most lethal living creatures.  

by Brian Dunning

Filed under General Science, Natural History

Skeptoid Podcast #396
January 7, 2014
Podcast transcript | Download | Subscribe



Yes, I know the correct grammar is "worst", but when you're talking about a creature that's bad, "worst" just doesn't have the right pizzazz. What's good enough for Leroy Brown is good enough for the plants and animals best able to kill us. Today we're going to look at the baddest of the bad plants and animals out there, as well as the biggest of the big and the oldest of the old. More importantly, we're also going to study how we know, and how we differentiate. The process of learning is almost always just as exciting as the conclusion.

(Word of warning: There is a lot of incorrect information about this subject on the Internet. If you're going to double-check any of these, or look for examples that are bigger, older, or badder, be very careful and double or triple check your sources. I did my fallible best to verify all of these, and had to exclude unverified claims from virtually every category.)

The Biggest

And by biggest, do we mean the tallest, longest, or most massive? As nearly every schoolchild has heard, the Blue Whale is the most massive animal that has ever lived, stretching up to 33 meters and 180 metric tons. Not even the longest sauropod dinosaurs were as long (despite unverified claims to the contrary). But the interesting fact comes when we wonder why, over the long history of the world including giant dinosaurs and everything else, the absolute biggest would just so happen to exist now? The answer comes from math, and it has to do with the Blue Whale's specialized feeding technique called lunge feeding. With a burst of speed, it opens its mouth so big as to gulp some 125% of its body weight of water, straining some half a million calories of krill. That's a big job with a high energy cost, and it requires a lot of calories to do it. As the size of the animal goes up, the energy cost increases faster than the potential energy gain from the food. It turns out that about 33 meters is the maximum size that a whale could grow using this feeding technique, and still consume enough calories to meet the requirement. This is why we've never found even a fossilized ancient whale ancestor that's been bigger, and why we'll probably never see a bigger creature.

If we're looking only at length, then the Blue may no longer be the king. Over 125 years ago, a Lion's mane jellyfish was found with tentacles as long as 37 meters, and a bootlace worm was washed up that measured 55 meters. But these have to be considered slightly dubious; although thoroughly documented, both measurements are thought to have been made when the animals were stretched out elastically to obtain the longest possible length.

You can find even longer animals if you relax the criteria to include undersea colonial critters, like siphonophores, in which the whole animal is actually a colony of connected individual zooids. The Portuguese Man o'War is a familiar example. One siphonophore called the Praya dubia can reach lengths up to 50m.

But to find the real all-time greats, we have to leave the animal kingdom. The most massive single organism ever, by mass, is the Giant Sequoia tree, found right here in my home state of California and the Sierra Nevada mountains. A single tree can mass over 900 metric tons, more than five of the heaviest Blue Whales. The tallest tree today is the Coastal Redwood, also found in my home state, standing 115 meters tall (also five of the largest Blue Whales). The tallest known living tree is named Hyperion. However, in the past, certain Australian Eucalypts have rivaled the Coastal Redwoods and may well have stood taller. The Ferguson Tree was reported in the 1870s as over 130 meters, but this specific measurement is considered unreliable.

For the biggest of the big we must, once again, redefine our parameters. Clonal colonies are plants or fungi that appear to be separate individuals, but in fact are physically connected underground and have sprung up as clones of the same original. These connections can sometimes grow old and break, or may be difficult to verify, so it's really hard for us to say for certain how large any given clonal colony is. We generally agree that the most massive single clonal colony is one of five giant fungi in an Oregon forest, clonal colonies of which are called genets. The largest of these genets is named the Humongous Fungus. It's probably between 7,500 and 35,000 metric tons; we really don't have a way to measure it any better than that. So it's open to rivalry from a grove of clonal aspen trees in Utah named Pando. Pando probably weighs about 6,000 metric tons and consists of around 40,000 trees. Other possible competitors to the title include underwater seagrass meadows and connected Coastal Redwood trees, of which it might take as few as six of the biggest to rival Pando.

The Oldest

The same ambiguity exists when we look for the oldest living things. Clonal organisms like Pando continue reproducing themselves, so the colony as a whole can reach an immense age, unlike its constituent clones who live normal lifespans. But clonal colonies are usually not the kind of thing that makes us go "Wow!" — as petty beings searching for sensationalism, we best love the amazing accomplishments of individuals.

So we're not that impressed to learn that Pando is at least 80,000 years old and possibly as old as 800,000, limited by the land on which it grows; none of Pando's individual trees are of a remarkable age. That's a clonal colony. Other clonal trees grow from the same stem, over and over again; and the oldest known of these is a Norway Spruce tree in Sweden named Old Tjikko. Its oldest roots are 9,550 years old, and for most of its years it lived as a shrub.

The Humongous Fungus is at least 1,900 years and possibly as old as 8,650 years. It's just as hard to date this fungus as it is to measure it.

But the Old Age crown of non-clonal, individual living multicellular things goes to Methuselah, a Great Basin Bristlecone Pine in California. It is 4,800 years old, give or take a few decades. We have to take core samples to get the exact ages of these trees, and we're pretty reluctant to do that. In the 1960s, a researcher was trying to find the limit of glacier coverage in the area by looking for the oldest trees. His coring bit got stuck in one tree, and with permission from the Forest Service, he and a ranger had to cut it down to retrieve the expensive bit. He was as shocked and sickened as all of us to find that it was the oldest creature ever discovered, at 4,900 years. It was posthumously named Prometheus.

Update: An older tree than Methuselah has been discovered in the same grove; 5,062 years old as of 2012. It is still alive, and was germinated even earlier than Prometheus. - BD

But what about good old vertebrate animals, familiar creatures like us, that run around and do things? Despite intense competition from koi and whales, the oldest ever was a Giant Tortoise named Adwaita, who died in a zoo in India in 2006, age 255 years old.

But we must admit being most impressed by the small number of species that are actually immortal. There are a number of sea creatures, such as the Immortal Jellyfish, whose mortality rate does not increase with age. In other words, they don't appear to have any biological causes of death. This particular jelly can revert from adult back to polyp and mature again, completely regenerating itself, and repeat the cycle indefinitely.

Not everyone needs amazing physiology to do such things, though. Among the simplest of all cellular organisms, the humble bacteria, was excavated in 2007 out of Canadian permafrost dated half a million years old — and still had active metabolic function.

The Baddest

There are all kinds of ways living creatures can kill you. Sharks and tigers can handily disassemble even the stoutest of men, and there are all kinds of plant, fungal, bacterial, and animal toxins that can do you handsome. Some animals may have especially deadly toxins, but may never attack. So to rank them all on a more-or-less equal scale, we're going to disregard the creature's likelihood to attack, and use what's called the LD50 of its toxin. LD50 is the lethal dose of a compound, administered all at once and measured in milligrams of toxin per kilogram of victim body weight, that will kill 50% of the test animals.

Despite being the closest thing we have to a standard measure of lethality, LD50 can be tricky and deceptive. Every toxin's LD50 level changes based on how the substance is delivered: is it inhaled? Injected under the skin? Rubbed on the skin? Injected into a muscle? These can make huge differences; a really poisonous animal might give you its poison in such a way that it doesn't hurt you nearly as much as if it had been administered some other way. Either way, thank a lab rat next time you die of a toxin with a known LD50.

The Clostridium bacteria are the worst of their kind, producing the botulinum toxin, the various types of which boast an average LD50 of about .001 (smaller numbers are more toxic). It's a neurotoxin, meaning it attacks your nerves and causes paralysis, not only to voluntary muscles but also to the heart. Tetanus, of similar lethality, also comes from Clostridium species. Botulinum toxin is one of the very deadliest compounds known.

Would you guess the deadliest plants are more or less toxic than the bacteria? They're more. You've heard of ricin, with its extremely deadly LD50 of .02, that comes from the castor oil plant; but have you heard of its close relative abrin? It comes from the jequirity plant in Indonesia, and it's about 75 times as lethal as ricin. It takes the toxicity crown of the plant kingdom.

Among our fellow animals, there is a lot of pretty bad venom out there. Spiders, scorpions, insects, centipedes, fish, jellyfish, octopi, and all sorts of beasties pack lethal toxins. But they all pale in comparison to their king of death, the Golden poison frog of Colombia, whose cutaneous toxin has an LD50 of .0001. That's about 100 times as potent than the poison of its nearest competitor, the Inland Taipan snake in Australia. But the taipan is much more likely to kill you, because it injects its venom subcutaneously, whereas touching a poison dart frog only gets it onto your skin.

Why bigger? Why older? Why badder? Why do we care? It's because those traits in nature, those which far exceed our own abilities as meager carbon life forms on this small round rock, put us on the map. They remind us that we're part of something that's bigger than ourselves. A massive mushroom and a giant jellyfish put us onto a universal stage of great majesty; an exhibition of awesomeness that adds to our own relevance, even as puny cogs in a magnificent machine. Swimming next to a Blue Whale, you don't have to think twice over whether your existence means anything; you only have to say "Yeah, I'm part of this extraordinary Earth."

And by the greatness of our fellow Earthlings comes the greatness of every little part of this stupendous system. There is magnificence in reality; one need look no further than our own ecosystem to find great beings that can probably rival life anywhere. Include the dark, warm oceans of Europa and the thick organic mists of Titan, and we may find that our immediate neighbors build us into an even more impressive solar system of life. So continue to celebrate the big, the old, the bad, the strong, the swift, and all else that makes us awesome.

By Brian Dunning

Please contact us with any corrections or feedback.


Cite this article:
Dunning, B. "The Biggest, the Oldest, and the Baddest." Skeptoid Podcast. Skeptoid Media, 7 Jan 2014. Web. 19 Jan 2017. <>


References & Further Reading

Adams, C. "What's the fastest-acting, most lethal poison?" The Straight Dope. Sun-Times Media, 18 May 2007. Web. 3 Jan. 2014. <>

de Vos, Asha. "Why are blue whales so enormous?" TED Ed. TED Conferences, 8 May 2013. Web. 3 Jan. 2014. <>

Eveleth, R. "How One Man Accidentally Killed the Oldest Tree Ever." Smart News. Smithsonian Media, 15 Nov. 2012. Web. 4 Jan. 2014. <>

Gupta, R. Handbook of Toxicology of Chemical Warfare Agents. Oxford: Elsevier, 2009. 339-352.

Schmitt, C., Tatum, M. The Malheur National Forest: Location of the World’s Largest Living Organism. Washington, DC: US Department of Agriculture, 2008. 2-8.

University of Copenhagen. "World's Oldest Bacteria Found Living In Permafrost." Science News. ScienceDaily, 28 Aug. 2007. Web. 4 Jan. 2014. <>

University of Florida. "Toxins of Biological Origin." Environmental Health and Safety. University of Florida, 30 Jul. 2012. Web. 5 Jan. 2014. <>


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