True Facts: Snake and Lizard Tongues

Dr. Kurt Schwenk
It was a pretty incredible gift to be able to work with Kurt on this episode. His work spans decades and it took multiple tries to understand it in a way that could be put together in a narrative. I am very grateful for all of his time, warmth and generosity. I had to leave many, many wonderful pieces of research and factoids out due to time constraints but I would urge any of you that are interested to dive deeper into his work.
His colleagues Dr. William G. Ryerson, Ms. Amanda E. Hewes and
Ms. Sara Horwitz contributed a great deal to some of the research that I mentioned.
Dr. Margaret Rubega ( deserves thanks for introducing me to Kurt in the first place.

Additional footage licensed from:
Envato Elements


  1. Kokichi's_Expired_Panta

    Kokichi's_Expired_Panta21 minute ago

    POV: You're here from teddy has an operation

  2. Hallebumba

    HallebumbaHour ago

    i want: Costasiella kuroshimae

  3. Proudly Brown

    Proudly BrownHour ago

    "you try this. Try flicking your tongue up and down very quickly. When humans do this its called HR violation". One of the many jules.

  4. Simond Frost

    Simond Frost3 hours ago

    Bro, I died when he said HR violation. Your a genius!

  5. ChogMils

    ChogMils3 hours ago

    uhh how about true fact about zefrank1

  6. LionGaming

    LionGaming5 hours ago

    i love this Chanel

  7. Korok Seed

    Korok Seed10 hours ago

    I’m not gonna lie, this was actually super interesting

  8. Torti Tongue

    Torti Tongue11 hours ago

    I recognize your voice from dear kitten! Or you may not be the person who voiced/narrated in it... sorry if you weren’t, you got a very nice voice and some very funny content here though friend XD

  9. Fluffy waffles fw.

    Fluffy waffles fw.13 hours ago

    The end card terrifies me

  10. pluspiping

    pluspiping17 hours ago

    Is this the kind of page where I can say "I'm always a slut for fluid dynamics" and people will, like, Get It? Love the in-depth sciencey ness of this video, it's a real treat, and thank you Dr. Schwenk!

  11. Martin Friman

    Martin Friman17 hours ago

    Shit, this was seriosly educational 😅

  12. FedBiker

    FedBiker18 hours ago

    The sound at 8:31got stuck halfway between my hippocampus and neo-cortex and is now on infinite loop.

  13. R3DLiFE

    R3DLiFE19 hours ago

    lmfao !!!! factfull and funny !

  14. Greer McNally

    Greer McNally20 hours ago

    'I'll give an arm and a leg to be the best at it' is now what I'm going to refer to whenever I talk about snakes.

  15. DeathLotus

    DeathLotus21 hour ago

    "When humans do this it's called an HR violation"🤣

  16. charizard4321

    charizard432122 hours ago

    Next time I see a snake I'm going to ask it what that tongue do😂😂

  17. Muneerah Adams

    Muneerah Adams23 hours ago


  18. Kevin Parks

    Kevin Parks23 hours ago

    Please do a video on the small and well named bird called a bushtit...

  19. rc casano

    rc casanoDay ago

    “When humans do this, it’s called HR Violation” The ending: 10:18

  20. Rafael Pasito

    Rafael PasitoDay ago

    When human do its called HR [human rights] violations! Hahahaha LoL

  21. Twisty99

    Twisty99Day ago

    Where is teddy now?

  22. MsSaraKirkpatrick

    MsSaraKirkpatrickDay ago


  23. MsSaraKirkpatrick

    MsSaraKirkpatrickDay ago

    Dammit, Jerry! Get it right! One minute in, and we're already yelling at you MULTIPLE TIMES!

  24. GAME-X AD

    GAME-X ADDay ago

    Teddy is still alive?

  25. Twisty99

    Twisty99Day ago

    Probably not

  26. Stormy Davis

    Stormy DavisDay ago

    God I want to go to therapy so I can call the therapist a brain witch despite their repeated insistence I stop.

  27. Muglorgrimlockable

    MuglorgrimlockableDay ago

    8:30 I rewound and even slowed it down me and the misses are dying and also copying it all day going randomly.....BLBMBMBLL

  28. Christian Terry

    Christian TerryDay ago

    This tongue will blow your mind. That’s what she said

  29. codeman7055

    codeman7055Day ago

    You should make videos for whales and sharks

  30. S CO PO

    S CO PODay ago

    All these lizards give me Schwenks

  31. Jesus jiu-jitsu

    Jesus jiu-jitsuDay ago

    Use this as a "I was today years old when I found out worm lizards were a thing" button.

  32. Asani Williams

    Asani WilliamsDay ago

    That mouth at the end was traumatizing

  33. Peter Meuller

    Peter MeullerDay ago

    “When humans do this it’s called an HR violation” 😂😂😂😂😂😂

  34. Hunter Clwminsom

    Hunter ClwminsomDay ago


  35. Anna Mishonova

    Anna MishonovaDay ago

    I self-identify as a smarty nipple

  36. Pumkinn

    Pumkinn2 days ago

    wheres mr teddy

  37. Jose Arellano

    Jose Arellano2 days ago

    HR violation 🤣🤣💀💀

  38. TheOnlyRealTapir

    TheOnlyRealTapir2 days ago

    HR violation :DDDD

  39. Samuel Varga

    Samuel Varga2 days ago


  40. Samuel Varga

    Samuel Varga2 days ago


  41. Samuel Varga

    Samuel Varga2 days ago


  42. Rukyura Myky

    Rukyura Myky2 days ago

    Why did i click while i was eating, i follow him since the start, i should have known better.

  43. Mr. W

    Mr. W2 days ago

    It will blow something, but it's not my mind.

  44. kl Chicago

    kl Chicago2 days ago

    I found someone trying to bite your style... but no one will ever say ... Baby's like you baby babys... that's what zefrank1 do......

  45. kl Chicago

    kl Chicago2 days ago

    5:27 on the video link

  46. kl Chicago

    kl Chicago2 days ago

  47. davidbwa

    davidbwa2 days ago

    I love your videos. I learn things and they make me laugh.

  48. Butacup Pucatub

    Butacup Pucatub2 days ago

    I need evolution to wink at the rest of 2020 and all of 2021 please 🧡

  49. NouraJ

    NouraJ2 days ago

    😂😂😂 oh Zefrank, both hilarious and education, I nearly peed myself laughing

  50. EternalBear Animates

    EternalBear Animates2 days ago

    Can you make a true facts video about kiwis? The bird not the fruit XD

  51. Iverson Paul Alay

    Iverson Paul Alay2 days ago


  52. Codeman785

    Codeman7852 days ago

    During this little snake rave

  53. Mo Na

    Mo Na2 days ago

    Could you da a video about the weirdest species of all... the HUMAN?

  54. harrison sim

    harrison sim2 days ago

    How can such a simple animal be so complicated

  55. Johnny Woods

    Johnny Woods2 days ago

    Brain witches lols, that's a far more accurate job title for psychiatrists.

  56. Owain Thomas

    Owain Thomas2 days ago

    I can't believe this is the same guy who did teddy has an operation

  57. happy man

    happy man3 days ago

    the way he describes things is the most realistic i have ever seen

  58. alex balfanz

    alex balfanz3 days ago

    This is how a healthy bon bon looks like

  59. fds fds

    fds fds3 days ago

    So that's what my tongue and lower lip look like slowed down when I make fart noises...

  60. Massage Dot Melbourne

    Massage Dot Melbourne3 days ago

    This one is absolute wall to wall 24-carat GOLD. A masterpiece. Just wonderful. Love your work, Ze.

  61. d_piyush

    d_piyush3 days ago

    No animals were harmed during the filming of this video but they died because of laughter 😂😂

  62. futsk01

    futsk013 days ago

    Ok that at the end was just excessive.

  63. Chris MacLean

    Chris MacLean3 days ago

    These documentaries are so fukking awsome!

  64. Travis B

    Travis B3 days ago

    "It's called an HR violation." That one got me good.

  65. Kevin Perry

    Kevin Perry3 days ago

    I hate this, and I love this

  66. deanthebean gaming

    deanthebean gaming3 days ago

    I’ve watched this about a dozen times, it’s just so great

  67. Nothsa Rekcap

    Nothsa Rekcap3 days ago

    Zerfrank: True facts about the Tyrannosaurus Shreks... ...oh wait hold on That’s a typo... True facts about the Tyranosaurus Sex... Jerry is this another typo? Jerry: ... Zerfrank: No? What do you mean it’s your browser history give me the actual script.

  68. Devilofether

    Devilofether3 days ago

    6:17 sorry, still here, and now I have subscribed

  69. Higor Araújo

    Higor Araújo3 days ago

    "It's sort of like they can smell in stereo." This is absolutely brilliant! As a veterinarian i'll always remember that humorous phrase in my lectures!

  70. Long Hoang

    Long Hoang3 days ago

    the outro is epic

  71. Andrew Pearson

    Andrew Pearson3 days ago

    OK like if you stuck out your tongue and tired to flick it up and down when he said that hahaha

  72. Meru Me

    Meru Me3 days ago

    hey remember ur teddy bear operation vid, haha. i watched that when i was like 6 👋 anyway hello again sir

  73. Timi Haze

    Timi Haze3 days ago

    The human tongue was the most disturbing

  74. Kerry Godbout

    Kerry Godbout3 days ago

    I had to pause midway through because I laughed so hard I spit my noodles onto my computer.

  75. rasheed gregory

    rasheed gregory3 days ago

    Dude I love your videos. I formative and extremely hiladious

  76. Angela Bartlett

    Angela Bartlett4 days ago

    "...HR violation." You are a funny man. xD

  77. Diadorim

    Diadorim4 days ago

    I love this man and his content with every fiber of my being

  78. Mönkey

    Mönkey4 days ago

    One of the best videos that came out on my birthday

  79. Michal Šeps

    Michal Šeps4 days ago

    S.T.E.R.E.O. TONGUES!!!

  80. yashua

    yashua4 days ago

    From now on I'm calling psychiatrists "brain witches"

  81. Sergio Di Martino

    Sergio Di Martino4 days ago

    Butt molecules in the air

  82. Sam E

    Sam E4 days ago

    "Can't fool me, Brain Witch!" 🤣

  83. DoomFinger511

    DoomFinger5114 days ago

    How many of you actually tried flicking your tongue in the air?

  84. nonya business

    nonya business4 days ago

    I can never go back to normal docs. I have been spoiled by zefrank and the art of the info doc comedey.

  85. Rusty Shakelford

    Rusty Shakelford4 days ago

    Can't fool me, brain witch!

  86. DiscoChixify

    DiscoChixify4 days ago


  87. Rhett Shumway

    Rhett Shumway4 days ago

    Oh man this is one of the best ones yet! BRAINWITCH, Seriously how does he so accurately and succinctly describe that profession?!?! LOVE IT

  88. Carbohighstakes

    Carbohighstakes4 days ago


  89. bocoy noiu

    bocoy noiu4 days ago

    That ending shot was disturbing in many ways...

  90. Hookie Doo

    Hookie Doo4 days ago

    This tongue will blow up your bicycle tires.

  91. White Fire Productions

    White Fire Productions4 days ago

    "Deep throating a squirrel's butt" Aaaallright, that's enough of that for today.

  92. Lady Tempest

    Lady Tempest4 days ago

    I've own snakes, monitors and other lizards... Men should take notes!!

  93. Lady Tempest

    Lady Tempest4 days ago

    @bocoy noiu great way to get a raise. Pun intended!!

  94. bocoy noiu

    bocoy noiu4 days ago

    When human do this it's called an HR violation 😂😂😂😂

  95. naik naik

    naik naik4 days ago

    hehe butt molecules

  96. Jack Davenport

    Jack Davenport4 days ago

    He’s back

  97. Jarred Uys

    Jarred Uys4 days ago

    All shag carpets are shag carpets of doom.

  98. adrian427

    adrian4274 days ago

    the last 10 seconds.......scarred forever

  99. Deadpool

    Deadpool4 days ago

    Pls do a colab with David Attenborough.

  100. sally caster

    sally caster4 days ago

    Why is no one talking about the end-

  101. Sarafina Delirium

    Sarafina Delirium4 days ago

    But why do the snake do? Dr. Schwenk know why!

  102. Adelphos89

    Adelphos894 days ago

    My cat enjoyed your lizard/snake tongue video too XD

  103. Bark Bark

    Bark Bark4 days ago

    XD awesome

  104. Kelsi Van Damme

    Kelsi Van Damme4 days ago

    One of my favorite videos you guys have ever done! The science and jokes in this one are so good 😂

  105. T J

    T J4 days ago

    Jobs that no-one wants #5438: product manager at Evolution, Inc. "Are you actually shitting me with this? All our users said they needed some way of cleaning and protecting their eyeballs. So we gave them Eyelid v1.0. Now this one user, Gordon effing Gecko, says "naah, fam - I don't want eyelids. I wanna lick my eyeballs clean." Sure, pal - we'll put it in the backlog.