What Animal Dominates Earth?

[INTRO ♪] Ask any casual science enthusiast what animal group has more species than any other, and they’ll probably say beetles. And there are a ton of beetle species—
more than 350 thousand, in fact. That’s about 22% of all species that we’ve identified and named so far, including stuff like bacteria. But some scientists think beetles’ time
at number one should come to an end. Other animal groups, they say, may be more deserving
of the title of “most species”. Though it’s tough to say which group that actually is, and it’s not just about knowing for curiosity’s sake. Having good estimates of how many species of beetle, plant, or bird there are is vital to tracking how those numbers are changing, and what we have to do to preserve them. It’s hard to actually pin down how many
species there are for a couple of different reasons. One is that species estimates are based on the number of species we currently know about, and we’re not familiar with an equal proportion of every group of animals. It depends on how interested we are in them and how easy they are to find. Beetles in particular were a popular collector’s item with old-timey naturalists, who gathered them for their exciting array of colors. And that interest meant there was ample funding and opportunity to go look for more beetles. Meanwhile, less charismatic animals, or ones that were smaller and harder to count, missed out— Animals like Hymenoptera, the group of insects that includes sawflies, wasps, bees, and ants. A 2018 paper published in the journal BMC Ecology argued that there are more species of hymenopterans than anything else, thanks in large part to parasitoid wasps. And if you’re thinking of the yellowjackets
in your garden, think again. These wasps can be barely bigger than a grain of sand and spend most of their life cycle inside other insects, making them very easy to miss. Parasitoid wasps target pretty much all insects, including ones that live in the ocean, in the Arctic, and deep down in the soil. And scientists think that these wasps are pretty specialized, meaning each species only targets a specific type of host. So according to the 2018 study, every insect, including all those beetles, might have not just one but potentially multiple species of parasitic wasp hunting them down. Also, insects have multiple life stages, and different wasps can target both the larval and adult forms. So two wasps for every beetle? I mean, you do the math. That’s not even counting parasitoids that target other parasitoids or ones that go for non-insect arthropods, like spiders. And it’s not just one study making this claim. Studies of sand dunes in California and insects in Canada estimate that hymenopteran species outnumber beetles by about two and a half times in that particular habitat. Now, if hymenopterans are not the most speciose animal group—that’s the technical term for having a lot of species—it’s probably still some sort of parasite. And that’s because parasitism is really popular in the natural world, evolving more than 200 separate times in 15 different groups of animals. And it makes sense!
Hosts are both food and shelter rolled into one. That makes nematodes, or roundworms, another contender for the most species-rich group. Not all nematodes are parasites, but many are and they target not just insects, but also other animals and plants. One 1993 study estimated there may be well over a million nematode species, though other estimates have varied wildly because they’re so understudied. Another paper from 2008 suggested that there may be between 75,000 and 300,000 species of nematodes parasitizing vertebrates alone. And nematodes have been found everywhere, including sediments deep down on the ocean floor. There’s probably nematodes in places
humans have never even been yet. Which is an important point: species estimates rely on what we can find, which means they rely on where humans can go. Now, you may have noticed that we’re comparing nematodes, which are an entire phylum of worms, to wasps and beetles, which according to the tree of life are technically orders. You know, kingdom, phylum, class, order. But even if you compare whole phyla, nematodes could still win out over arthropods, the phylum that contains wasps and beetles. We think there’s roughly a million of each, but there’s so much variation in those estimates that it’s tough to call. And we don’t assign those groups—phyla, classes or orders—based on how big they are, but that’s a whole other story. And then there’s the question of charisma, which could explain why Diptera, the order that includes true flies, have been overlooked. They might grab your attention when they’re buzzing around your living room, but there aren’t many people who’d say they… like flies. Not like people like beetles. But when scientists do get to studying them, they find a surprising number of species. Like a study from 2018 that found more than 4000 species of true flies in a four-hectare patch of Costa Rican rainforest. Current estimates put Diptera at more than a million species, easily surpassing beetle numbers. There’s that million number again … I
mean, we told you it was tough to call. Flies can live almost anywhere on land and, as larvae, can feed on everything from plant nectar to vertebrate blood. And that’s important too: for a group of animals to stand a chance at being the most speciose, it has to show variety in where it lives, what it eats, and how it survives in general. And that could mean making yourself comfortable inside a host like a parasite does, or being able to find homes in some of the most remote places on Earth. But, if there’s anything we’ve learned from trying to count all of the animals, it’s that what’s right in front of us isn’t always a good indicator. If we want to know what’s out there, we’ve got to go look for it. Thank you for watching this episode of SciShow. If you want to help support the channel, you can do so over on Patreon. We’ve got the best community of supporters around, and you can meet and chat with them—and some of our
team—over on our patron-only Discord. If you want to get started, head over to patreon.com/scishow. [OUTRO ♪]

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100 Responses

  1. John Barber says:

    Buckey Katt.

  2. Xbox Freak says:

    Imagine if someone could control all ants on the planet, they could kill a billion humans inside of a day. Send the ants in to peoples throat and choke them and then onto the next human.

  3. 111 says:

    Humans. Next question.

  4. CDOSRUN says:

    nope we have one too many animals called idiots on this planet effing things up with their prison/devil dollars

  5. Daryl Supercalifragilisticexpialidocious says:

    Trumptards ?

  6. sina k says:

    This guy is the reason i dont click on yourstuff no more. He just dont sit right with me….

  7. Scrap & Pallet Man says:

    3:59 'nother' IS a word. usage dictates.

  8. mowhar says:

    So.. if "we" are created in Gods image. God is statistically probably a parasite??

  9. Nick Walker says:

    My feline master told me to tell everyone that Cats dominate earth.

  10. Anonymous Coward says:

    IMO, the answer should rely on total biomass, not number of species. (Even number of individuals would make more sense than counting species.)

  11. Aly Jack says:


  12. borbo23 says:

    13 beetles disliked this video.

  13. Perry Dowd says:

    The Beatles will always be Number 1!

    The Nematodes never sold a single record!

  14. Sahil Pethe says:

    What about ants though? I think they dominate us many times more than our human population.

  15. Rose Gold says:

    Has scishow made a video explaining the pyramid of biological classification? If not I’d love to see that.

  16. Trilha Sem Fim says:

    i was thinking on ants…

  17. LKNANML says:

    I'm thinking insects or bacteria. Onto the video.

  18. Pamela Mays says:

    I'm partial to Beatles native to Liverpool.🐞🐞🐞🐞

  19. David Jameson says:

    Most species?
    How about largest population?
    Biggest collective biomass?

    There's more than one way to "dominate" statistics.

  20. William Tredeau says:

    The answer of the question is humans.,😀😀😀

  21. KendrickMan says:

    Just for those who are curious, in plants, the Asteraceae family (think sunflowers), and Orchidaceae families are assumed to be the most divergent lineages. I'm too lazy to google specifics for this comment, but I think there are roughly 60,000+ species of orchids, 75,000+ species of asters, or thereabouts. Look into it, it's fascinating. They both speciate for different reasons. Orchids often have specific pollenators.

  22. theshuman100 says:

    ocean wasp ocean wasp ocean wasp

  23. thatguy 00 says:

    scientist counting flies
    “1…2..3.. wait did I already count that one?”

  24. Algomi says:

    The argentine ant………..

  25. Irene Lee says:

    2:50 i love nematodes 😤

  26. Endymion766 says:

    Them: Tiny worms.
    Me: –oh

  27. Z Worm says:

    Nothing in nature is certain except Extinction. So why is knowing numbers of minor species so important? Will it stop extinction?

  28. frankcastle498 says:

    Congrats on six million subs!

  29. Patrick McCurry says:

    I wonder what individual species contains the most numbers of individuals… or collectively comprises the most mass. Just as unanswerable questions, but still interesting, IMO.

  30. karina833 says:

    SciShow, the channel now bringing us more videos based on conjecture and speculation than actual facts. Whenever a vid starts with "some scientists" you know it ain't going to be a factual video, but just a bit of conjecture. This channel is slowly but surely sinking down to the level of science news we get on TV, crap.

  31. NAGA HARISH GIRI says:

    Thanks for educating us. Being an entomologist, I would like to convey my sincere thanks for this episode

  32. Infernoraptor says:

    Back up a sec, "insects in the ocean"?

  33. AjjHawke 7jj says:

    Bugs is my guess

  34. The DDV Show says:

    What Animal Dominates Earth?

    The rational animal, humans.

  35. B R I C K. says:

    Dang nematodes!

  36. Philippe H. says:

    The dominant animal on Earth is Homo Sapiens Sapiens, aka : HUMANS.

  37. TMB247 says:

    THANK YOU! Not a single mention of algores religion… very refreshing

  38. William Vincent says:

    Wasps are such freaking jerks.

  39. Game slayer404 says:

    What about which species has the highest number of individuals and not just an animal groups species?

  40. Hingle McCringleberry says:

    Big shout out to gravity for holding it down for all the species on the easy 💯💯

  41. Mxrgan Hex says:

    Hum… nvm

  42. Obama Doesn't Love Me No More says:


  43. G A M E B O I says:

    Answer: internet trolls

  44. Jetlag Moto says:

    Tbh I kind of want a beetle box now

  45. JohnnyLeven says:

    Wait what? People like beetles more than files? I don't like files at all, but I really hate beetles.

  46. painedumonde says:

    See for each life, there is a Reaper, even parasitic wasps. Reapers are the dominant species in the universe. Waiting for a counterargument.


  47. Daniel Blanco says:

    Do you guys think you could do a video of the comparison of animal and human immune system on strength levels towards each other ?

  48. Ophelia Ronin says:

    I like THE Beatles

  49. It DontmatterPth says:

    Was watching an old science conference video a guy was talking about Hawking radiation. Learned in 2019 we got a picture of a black hole's disc does this prove Hawking radiation or only that black holes are a real thing? I thought we had proven Hawking Radiation and it just wasn't some math theory idea thingy like string theory which is unproven?

  50. Edwyn Choi says:

    Don't worry the devs will nerf them in the next patch

  51. Existenceisillusion says:

    Q: What animal dominates Earth?
    A: Yes

  52. Paul Dana says:

    I would think bacteria would be the most numerous of all organisms.

  53. Paul Dana says:

    Remember folks, Adam NAMED all of the animals. All 50 million of them so Eve had to play with herself.

  54. Dee B says:

    Yeap .. The Beatles .. dominate the world.

  55. Dee B says:

    Do we call Flies Flies because they fly?

  56. My Name is JAFO says:

    My money's on the dreaded Molemen who live beneath the Earth's crust.

  57. GotPotatoes24 says:

    I wish kitty cats had the most species.

  58. mythplatypuspwned says:

    Parasitoid wasps in the ocean? I'd like to know more.

  59. currypac says:

    I thinking worms

  60. tfbbm says:

    how about let's not consider any life in particular to be special and consider ever specie worth protecting,, stop Government / Corporation culling of life

  61. Chaitanya says:

    I want to see the comparison between most number of animal species and the most number of plant species

    I'm betting my money on plants

  62. Piransu says:

    What, isn't genetically modifying the parisitic wasps to render their hosts sterile a good way for pest control? Especially since they only target specific species.

  63. Furat Ceylan says:

    insects and parasitic wasps in the ocean?! MARINE INSECTS?

  64. razzle dazzle says:

    I vote on cilliates .

  65. Jack Berry says:

    Nematodes are people too!!!

  66. Beezus C Hrist says:

    … The type of animal that could make videos like this…

  67. Adel Abdelazim says:

    Can you add an Arabic translation for the videos?

  68. AtarahDerek says:

    What vertebrate dominates the earth? Besides humans. There may be a lot of us, but we're still only one species.

  69. ᠯᡠᠪᡵᡳ ᠮᠠᡳᠯᠠᠰᡠᠨ says:

    The sheer number of beetles and the juices they provide are the main reason why betelgeuse is about to explode at any minute.

  70. CockSmasher9000 says:


  71. Johnny Appleseed says:

    Species have come and gone for the entire history of life. Preserving certain species should not be an end in and of itself.

  72. Logan Adams says:

    In conclusion: Parasite deserved the Oscar.

  73. Clutchyfinger says:

    The subterranean crustaceanoids scoff at your claim to knowledge of the order of the surface's hierarchy. You worthless specks will fall to the claw of King Lobstramere once he breaches the crust of your fragile mantle. 🦀🦐

  74. Buggy Boy says:

    You forgot to mention mites which alone might outnumber insects, mites are believed to be more specious than nematodes too.
    If that's really the case then arthropods may very well be around 8-10 million species strong as a whole!

  75. Gareth Michell says:

    But as your 'tree of life is messed up' video says, the 'groups' are pretty poorly defined, so why do we care which group is biggest?

  76. Hezekiah Filipo says:

    What's an example of a parasitic wasp attacking an oceanic organism please?

  77. Frank Costello says:


  78. Ahimsa42 says:

    “Man is an almost hopelessly conceited animal, this pygmy! He thinks that not only the earth with all that it contains was created for his benefit, but also the sky, the sun, and indeed, the whole universe, as far as he has any knowledge of it, were designed for his purposes and welfare."- Ernest Bell

    “The most calamitous and fragile of all creatures is man, and yet the most arrogant. (…) Is it possible to imagine anything so ridiculous as that this pitiful, miserable creature, who is not even master of himself, should call himself master and lord of the universe? It is apparent that it is not by a true judgment, but by foolish pride and stubbornness, that we set ourselves before other animals and sequester ourselves from their condition and society.”-Michel Montaigne

    “All our lauded technological progress — our very civilization – is like the axe in the hand of the pathological criminal.” ~ Albert Einstein

    "A universe is indeed to be pitied whose dominating inhabitants are so unconscious and so ethically embryonic that they make life a commodity, mercy a disease, and systematic massacre a pastime and a profession."- J. Howard Moore

    “Aren’t humans amazing? They kill wildlife – birds, deer, all kinds of cats, coyotes, beavers, groundhogs, mice and foxes by the million in order to protect their domestic animals and their feed. Then they kill domestic animals by the billion and eat them. This in turn kills people by the million, because eating all those animals leads to degenerative – and fatal – health conditions like heart disease, stroke, kidney disease, and cancer. So then humans spend billions of dollars torturing and killing millions more animals to look for cures for these diseases. Elsewhere, millions of other human beings are being killed by hunger and malnutrition because food they could eat is being used to fatten domestic animals. Meanwhile, few people recognize the absurdity of humans, who kill so easily and violently, and once a year send out cards praying for “Peace on Earth.”~ David Coates

  79. Limey says:

    I find it very unprofessional when people say "a whole nother". "Nother" is not a word, it's "a whole other" or "another whole".

  80. Scott Whatever says:


  81. Scott Whatever says:

    Okay, this is stupid. The animal that dominates Earth composes the most biomass, period. Not number of species.

  82. Brenda Krieger says:

    Beetles are truly amazing creatures🐞🐞

  83. Gyrre says:

    Parasites, eh? Like career politicians and multinational corporate execs?

  84. IIARROWS says:

    We don't even have 7 fixed groups… why do you keep iterating that?

  85. WaRRioR says:

    Phages? Or ants?

  86. The Very Best of Alex says:

    The thought that there are that many parasitious wasps gives me anxiety

  87. Dan Bhakta says:

    Left-wing parasites.

  88. Terry Maximum-Effort says:

    That was really interesting! I feel like you and QI should do a massive cross over!

  89. Xavier Zara says:

    •major mysteries of the natural, biological world yet to be solved
    Heavily investing in space exploration for novelty

  90. Rick Karrer says:

    I hate to be that guy, but isn't it, "Which animal dominates Earth?"?

  91. Greg Miller says:

    ..my favs are John, George, Ringo & Paul 😀

  92. Breezy says:

    Without watching this video I’ll say the Ant.

  93. spindash64 says:

    Are humans in the reverse category of this type of record, as the last remaining hominid species?

  94. devilzal says:

    Nematodes are people too

  95. Leo5191 WR says:

    Arthropods vs Nematodes vs any single Bacteria phylum?

  96. 3 Possums in a Trenchcoat says:

    hard to…. pin down? ;D

  97. Dean Robbins says:

    Lotsa bugs, got it.🥃🍺

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