True Facts: Hippopotamus

True Facts: Hippopotamus

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Special Thanks to:

Dr Eduardo J Fernandez, University of Adelaide
Dr Jonas Schoelynck, University of Antwerp
Dr Julio de Castro
Dr Frank Fish, West Chester University
Dr Maria Maust-Mohl, Manhattan College
Dr Christopher Dutton, University of Florida
Dr Joseph Dudley, University of Alaska
Dr Todd McWhorter, University of Adelaide
Dr Victoria Inman, NSW Dept. of Planning and Environment
Dr Philip Gingerich, University of Michigan
Dr Rebecca Lewison, San Diego State University

Peter Geraerdts,

Lex Hollmann @LexHollmann
Johan Vermeulen | The Nature Box @thenatureboxfilms
Amos Kaggwa
San Diego Zoo Wildlife Alliance @SanDiegoZoo
ZSL Whipsnade Zoo @ZslOrg1826
Prof. Gordon T. Taylor
PapaArtzzi*- Art Ryan,

Latest Sightings @Latestsightings
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Barklow, William E. Amphibious communication with sound in hippos, Hippopotamus amphibius, Animal Behaviour, Volume 68, Issue 5, 2004, Pages 1125-1132, ISSN 0003-3472,

Blowers, Tracy, “Social Grouping Behaviors Of Captive Female Hippopotamus Amphibius” (2008). Electronic Theses and Dissertations. 3459.

Coughlin, Brittany L. , Frank E. Fish, Hippopotamus Underwater Locomotion: Reduced-Gravity Movements for a Massive Mammal, Journal of Mammalogy, Volume 90, Issue 3, 2 June 2009, Pages 675–679,

Dudley, J.P., Hang’Ombe, B.M., Leendertz, F.H., Dorward, L.J., de Castro, J., Subalusky, A.L. and Clauss, M. (2016), Carnivory by hippos and ecology of anthrax. Mammal Review, 46: 191-203.

Dutton, C.L., Subalusky, A.L., Sanchez, A. et al. The meta-gut: community coalescence of animal gut and environmental microbiomes. Sci Rep 11, 23117 (2021).

Gatesy J, Hayashi C, Cronin MA, Arctander P. Evidence from milk casein genes that cetaceans are close relatives of hippopotamid artiodactyls. Mol Biol Evol. 1996 Sep;13(7):954-63. doi: 10.1093/oxfordjournals.molbev.a025663. PMID: 8752004.

Geisler, J., Theodor, J. Hippopotamus and whale phylogeny. Nature 458, E1–E4 (2009).

Gingerich PD, Haq Mu, Zalmout IS, Khan IH, Malkani MS. Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan. Science. 2001 Sep 21;293(5538):2239-42. doi: 10.1126/science.1063902. Epub 2001 Sep 19. PMID: 11567134.

Graeme, Shannon, Sadler Phoebe, Smith Joanna, Roylance-Casson Eleanor and Cordes Line S. 2021Contrasting selection pressure on body and weapon size in a polygynous megaherbivoreBiol. Lett.172021036820210368,

Gray NM, Kainec K, Madar S, Tomko L, Wolfe S. Sink or swim? Bone density as a mechanism for buoyancy control in early cetaceans. Anat Rec (Hoboken). 2007 Jun;290(6):638-53. doi: 10.1002/ar.20533. PMID: 17516430.

Inman VL, Kingsford RT, Chase MJ, Leggett KEA (2019) Drone-based effective counting and ageing of hippopotamus (Hippopotamus amphibius) in the Okavango Delta in Botswana. PLoS ONE 14(12): e0219652.

McCauley, D. J., T. E. Dawson, M. E. Power, J. C. Finlay, M. Ogada, D. B. Gower, K. Caylor, W. D. Nyingi, J. M. Githaiga, J. Nyunja, F. H. Joyce, R. L. Lewison, and J. S. Brashares. 2015. Carbon stable isotopes suggest that hippopotamus-vectored nutrients subsidize aquatic consumers in an East African river. Ecosphere 6(4):52.

Maust-Mohl, M., Reiss, D. and Reidenberg, J.S. (2019), A Comparison of Common Hippopotamus (Artiodactyla) and Mysticete (Cetacea) Nostrils: An Open and Shut Case. Anat Rec, 302: 693-702.

Maust-Mohl, M., Soltis, J., & Reiss, D. (2018). Underwater click train production by the hippopotamus (Hippopotamus amphibius) suggests an echo-ranging function, Behaviour, 155(2-3), 231-251. doi:

Saikawa, Y., Hashimoto, K., Nakata, M. et al. The red sweat of the hippopotamus. Nature 429, 363 (2004).

Sulman J R, Madelyn G C, Irina A K. Correlation of Bone Density in Aquatic and Semiaquatic Animals to Ecological and Dietary Specializations. Open Acc Res Anatomy. 2(3). OARA.000537.2020.
DOI: 10.31031/OARA.2020.02.000537

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49 Responses

  1. Ze Frank says:

    Check out Curiosity Stream! Go to and use code: zefrank23 to get 25% off when you sign up!

  2. Jake Norton says:

    I remember reading that hippos were the one animal Steve Irwin refused to get near to. That’s how unpredictably violent they are.

  3. RevokFarthis says:

    I absolutely love Ze’s little “kill me” whenever he makes a pun

  4. Dan_Ganing_Fan says:

    After being blessed with the “oppih”, we finally get a True Facts about its closest relative and one of my favorite animals. And as always, Ze Frank doesn’t disappoint.

  5. Come Fast To Get Into My Body says:

    I was blessed to grow up in a place where I could see or hear them every day. They are fascinating creatures

  6. Timothy Y. says:

    Some additional information on hippo’s phylogeny:
    Not only are whales their closest living relatives, they are also more closely related to ruminants such as bovines, sheep, deer, and giraffes, than they are related to pigs.
    Also something I love is that the clade that includes both cetaceans and hippos is called Whippomorpha.

    • Sethrael the Bard says:

      Another fun fact is that the dolphin’s closest relative are actually cows. That’s right, nearly all bovine species evolved from dolphins. I guess they figured that eating fish and swimming all day was too much work, so they decided to ditch the fins, crawl up on the land and start eating the grass. As so, we can all look around and see cows as just lazy dolphins. Eat beef! Dolphin meat seasoned by evolution!

    • In the Lord's Army says:

      @Jenny John What are you comparing it to? Modern metal isn’t even metal anymore that’s why you need ten-thousand genres to describe it. If you are comparing it to the nineties though I would have to agree with you. I am a child of the eighties so I was actually there and at the prime age to enjoy it.

      Music before 2000 > Music after the year 2000

    • Jenny John says:

      @Rasputin Pretty much all 80s metal bands were bad… but not in a good way… :O

    • Rasputin says:

      Whippomorpha sounds like a bad 80s metal band. 😂

    • Tragoudistros.MPH says:

      ​@Dessa you’re right, whales still have hands in their flippers.

      The OP list has even and odd toed ungulates. (Confused me for a moment too!)

  7. camronsavell says:

    Telling the hippopotamisses from the hippopotamisters broke me. Great job. Love this channel and wish you could narrate all sorts of things.

  8. Gamma Gong says:

    We’re reaching ‘Dad Joke’ critical mass.
    And I’m here for it.

  9. Rickus LastName says:

    “it’s a sad thing, but a true thing”
    Might as well be life’s motto

  10. Zanne says:

    The phrase “science hippo” was everything I didn’t know I needed

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