June 1996 PMID 8693059

The evolution of endometrial cycles and menstruation.

B I Strassmann

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Mentions

109
Peak: 38 in Jan 2020
across 5 sources since Apr 2016

Extended reach

2,718,080
potential audience

Total likes

60,836

Video views

2,365,791

Mentions per month

Apr 2016 – Sep 2025

Where it's discussed

  • X / Twitter99 posts
  • News4 articles
  • Bluesky2 posts
  • YouTube2 videos
  • Blogs2 articles

AI synopsis

What people are saying

The discussions overwhelmingly show interest and engagement with the article, with many examples such as references to videos explaining menstruation and hypotheses like the 'Choosy Uterus'. The tone varies from curiosity to correction, highlighting a collective effort to understand the biological and evolutionary significance of menstruation, which underscores its moderate impact on public scientific literacy.

AgreementModerate agreement

Most discussions recognize the validity of the article's hypothesis about menstruation's energy-saving function, with some emphasizing its evolutionary role.

InterestHigh interest

Many comments express curiosity and enthusiasm about understanding why humans menstruate, especially since most mammals do not.

EngagementHigh engagement

Numerous participants reference videos, scientific hypotheses like the 'Choosy Uterus', and debate how menstruation relates to human biology, showing deep engagement.

ImpactModerate impact

While some recognize the scientific relevance, the overall impact appears moderate, mainly contributing to increased awareness but not prompting broad societal change.

Abstract in brief

  • The traditional hypothesis suggests menstruation evolved to protect the uterus from pathogens by shedding infected tissue and delivering immune cells, but this theory was not supported by the evidence.
  • The author proposes an alternative explanation: the endometrial lining is shed or resorbed when implantation fails because this cyclical regression is less energy-consuming than maintaining an active endometrium.
  • The cyclic changes in endometrial energy use are part of the body's overall metabolic cycle, with significant energy savings during menstruation and non-breeding periods, helping females conserve energy and maintain body mass across different environments.]

Top posts

Most liked on X and Bluesky
SciShow
@SciShow · X

Most mammals don't menstruate, so why do humans? Scientists have had some bizarre ideas over the centuries, but we seem to finally be getting somewhere. https://t.co/vT0AXVYcPZ https://t.co/SgUNrTqRIY

Jan 23, 2020 · 26 likes · 3 shares · 115,396 followers View post →
Crystal
@Violett767 · X

@OnlySeverinsen @finelinetears @sarahlugor https://t.co/4w7ZjJEfpV it’s actually really interesting. Humans are one of the only species that have such inconvenient periods

May 17, 2021 · 18 likes · 32 followers View post →
A
@piekna · X

@firebird2110 @zaelefty @SciShow And this episode "Why Do People Have Periods When Most Mammals Don't?" that fails to mention women or girls once in its 12 minute running time. https://t.co/bo4bVz7PAn

Aug 3, 2020 · 11 likes · 3 shares · 909 followers View post →
boysvswomen.com
@boysvswomen · X

.@scishow drinking game rules - 1 sip every time they avoid using male/female Their latest video is on periods: F̶e̶m̶a̶l̶e̶ Humans Menstrators Half of People We/Us Half of humanity Menstrating people People Parent Host Half of us People whose uteruses https://t.co/WFkT0fwsvl

Jan 22, 2020 · 10 likes · 2 shares · 12,049 followers View post →
the 1st rule of Wife Club
@cpi.pinball.horse · Bluesky

JKR struggling to define 'women' like

Aug 9, 2025 · 8 likes · 1 share View post →
Mykhailo Grosman Ⓐncom
@GrossmanMikhail · X

@russpolushko Хороший вопрос. Есть несколько гипотез. https://t.co/4lmUWHuOjt

May 2, 2023 · 7 likes · 483 followers View post →

All mentions

Evolution of Menstruation and Female Reproductive Cycles

Periods are a necessary part of human reproduction, but most other animals don't have them. The traditional hypothesis suggests menstruation evolved to protect the uterus from pathogens, but evidence does not support…

Seeker · Apr 9, 2016 1,038,227 views
La Fortuna ♡
@themostazezo · X

@dr4matics Actually it's better that humans have periods it most likely served a very good evolutionary purpose https://t.co/lX5ANYzGdl

Sep 29, 2025 · 839 followers View post →
the 1st rule of Wife Club
@cpi.pinball.horse · Bluesky

JKR struggling to define 'women' like

Aug 9, 2025 · 8 likes · 1 share View post →
Shally
@sahradayi · X

https://t.co/D2h3Ft0D6A 1> the more I learn about the body’s subtle, built-in intelligence, the more it exposes how primitive and surface-level our everyday idea of 'consciousness' really is. It's like human biology devours psychology-frameworks for breakfast.

Aug 9, 2025 · 1 like · 1,382 followers View post →
Will-O 2pt0
@Will_O2pt0 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/xefV58fDxf via @YouTube

Aug 5, 2025 · 1 like · 132 followers View post →
Moonbunny
@kitsunefyuu · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/UEKBVcsWSu via @YouTube

Aug 2, 2025 · 25 followers View post →
ciken
@notexlst_ · X

@writemenfess btw kemarin nonton ini semoga menambah insight sendernya juga https://t.co/RjVayWtx5o

Jul 29, 2025 · 1 like · 14 followers View post →
acdc25.bsky.social
@acdc25.bsky.social · Bluesky

youtu.be/XXzFO1kEBfY

Jun 29, 2025 View post →
Deborah J. Ross
@DeborahJRoss · X

Why Do People Have Periods When Most Mammals Don't? If you need a break from the news, here's a great video on #menstruation. Everyone should know this stuff, especially what we've learned since "health ed" classes (mine were in the 1960s). https://t.co/DnqeA9V5Aj

Jan 28, 2025 · 1,457 followers View post →
Mıtsuĸou ɘnjoyɘɾ
@itazura_lolita · X

Source: https://t.co/N1T1KEqt23

Sep 11, 2024 · 250 followers View post →
J
@The_Feminist_TM · X

@AmandaMontagne @RachelUndercovr @ask_aubry these two videos do a good job explaining. https://t.co/prqMkf4JrF https://t.co/5ujBN8lot9

Oct 31, 2023 · 1 like · 15,071 followers View post →
Myra
@mitsubey · X

Wow. OP needs to educate themselves on the fact that humans are one of a very few mammals that actually bleed during menstruation while most other mammals don't, not to mention other animals don't bleed either. Geezus. https://t.co/1YqOWHc6es https://t.co/2iZJ8fQJSF

Oct 31, 2023 · 1 like · 2,959 followers View post →
Bennet
@benotoho · X

@DrMel_ @Living_JustCus https://t.co/PTqMldZkId

Oct 22, 2023 · 346 followers View post →
Matthew
@Matthew49200183 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/61oPcK0yAa via @YouTube

Sep 21, 2023 · 4,787 followers View post →
muse_neko LUVS BTS⁷
@muse_neko · X

I love this video for the fact that it accurately caused fetusus "parasites" alone. https://t.co/cjUbjTGinG

Sep 13, 2023 · 985 followers View post →
AceDolo
@AceDoloX1 · X

Found this dope video https://t.co/zTe7FKVBkK

Aug 30, 2023 · 3,406 followers View post →
Ravenwood
@rawnwyd · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/zCA5nkuc3c via @YouTube

Aug 27, 2023 · 454 followers View post →
strategic rambler
@AllPurposePilot · X

@FriedrichE49 @sunnydaejones this is false. watch the first 45 seconds. https://t.co/ep4GXn0QOW

Jul 23, 2023 · 255 followers View post →
strategic rambler
@AllPurposePilot · X

@JasssGonza @inallcreashun @sunnydaejones they don't. https://t.co/ep4GXn0QOW

Jul 23, 2023 · 255 followers View post →
strategic rambler
@AllPurposePilot · X

@sunnydaejones dogs don't get periods. their bleeding comes from the vagina, not the uterus and it happens before ovulation. source: https://t.co/ep4GXn0QOW

Jul 23, 2023 · 1 like · 255 followers View post →
Tiziana Leone now on @tizianaleone.bsky.social
@tizianaleone · X

"Twelve months of amenorrhea save an estimated 130 MJ, or the energy required by one woman for nearly half a month." Love papers like these. Thanks @julietmce for this little jem https://t.co/jAeH6fZ95g

Jun 23, 2023 · 1 like · 1,643 followers View post →
Alina
@k_ai_li · X

@KuchaMusora Конкретно про рукокрылых не знаю литературу( Strassmann B. I. "The evolution of endometrial cycles and menstruation"; Profet M. "Menstruation as a defense against pathogens transported by sperm"; Martin R. D. "The evolution of human reproduction: a primatological perspective".

Jun 23, 2023 · 5 likes · 3 followers View post →
Maar Herrera
@Maaar_Herrer · X

Strassmann, I. (1996). The Evolution of Endometrial Cycles and Menstruation. June 01,2023. Retrieved from https://t.co/jEPHKmR6gz

Jun 2, 2023 View post →
Mykhailo Grosman Ⓐncom
@GrossmanMikhail · X

@russpolushko Хороший вопрос. Есть несколько гипотез. https://t.co/4lmUWHuOjt

May 2, 2023 · 7 likes · 483 followers View post →
Njut Tabi Godlove
@masecdante · X

Liked on YouTube: Why Do People Have Periods When Most Mammals Don't? https://t.co/4asIvLj1MI

Mar 22, 2022 · 5,559 followers View post →
Njut Tabi Godlove
@masecdante · X

Mar 21, 2022 · 5,559 followers View post →
yohiverse
@yohiverse · X

@m_bluesoul https://t.co/9dbnMvciAF

Sep 3, 2021 · 1,572 followers View post →
Maÿa Cantú
@aynomayac · X

Hmmm… you are right! In 1996 this was debunked. My sexual education class was before that. https://t.co/xx32Z5pf4E https://t.co/2Ft53LZ2fH

Aug 27, 2021 · 514 followers View post →
Crystal
@Violett767 · X

@OnlySeverinsen @finelinetears @sarahlugor https://t.co/4w7ZjJEfpV it’s actually really interesting. Humans are one of the only species that have such inconvenient periods

May 17, 2021 · 18 likes · 32 followers View post →
Gemma Cornibert
@lesley_gemma · X

https://t.co/JQAjbQOHcl

May 13, 2021 · 13 followers View post →
Imago
@floralglitch · X

WELL THAT'S THE BIG QUESTION, INNIT.

May 7, 2021 · 123 followers View post →
Stultum facit fortuna, quem vult perdere
@FairishGodmum · X

@RustBeltRebel 2. Periods, and theories on why humans have them https://t.co/yZCys7xcSE

Apr 30, 2021 · 573 followers View post →
POTUS Krass
@CrassKrass · X

https://t.co/E3omVezzrL @SciShow For the following reason, a baby is NOT a parasite: Mother and baby do NOT INTEND to harm each other. Comparison: an actual parasitic relation, one/both intends to harm the other That vid part is interesting until you call the baby a parasite.

Apr 29, 2021 · 65 followers View post →
Thomasina
@LadyMerveilles · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/5tsC6A5kjI via @YouTube

Apr 25, 2021 · 283 followers View post →
L is still a semantic error
@preserve_root · X

FYI for people with menstruation power.... Why Do People Have Periods When Most Mammals Don't? https://t.co/qKWW0FGQKH

Apr 25, 2021 · 397 followers View post →
morceno_
@morceno_ · X

@chevrolexia https://t.co/QSo4YV5lmJ Sem zuera esse vídeo do SciShow é bom demais porque eu tinha essa mesma pergunta PS: todos os vídeos do SciShow são bons demais veja todos

Feb 27, 2021 · 1 like · 66 followers View post →
Portal
@artficialportal · X

RT @karimnas_: @artficialportal "There is a correlation between species that have overt menstruation and those that have a large uterus rel…

Jan 24, 2021 · 1 share · 8,403 followers View post →
كريم ناس
@karimnas_ · X

@artficialportal "There is a correlation between species that have overt menstruation and those that have a large uterus relative to the adult female body size." https://t.co/UPskiHf9uo

Jan 24, 2021 · 2 likes · 1 share · 10,860 followers View post →
Gustavo Godoy
@gutzii_godoy · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/3DffhlBb3l Ver menotóxicos.

Dec 2, 2020 · 181 followers View post →
BD Guitar
@BuckDharma2 · X

RT @boysvswomen: .@scishow drinking game rules - 1 sip every time they avoid using male/female Their latest video is on periods: F̶e̶m̶a̶…

Oct 27, 2020 · 2 shares · 1,880 followers View post →
Eva Poen
@EvaPoen · X

RT @boysvswomen: .@scishow drinking game rules - 1 sip every time they avoid using male/female Their latest video is on periods: F̶e̶m̶a̶…

Oct 26, 2020 · 2 shares · 8,481 followers View post →
abhel
@bhlzky · X

Choosy Uterus Hypothesis is my favorite thing today. And to women everywhere, I'm so sorry and the species thank you. https://t.co/PPNbLgJK88

Aug 30, 2020 · 268 followers View post →
Leopards
@joy_afi · X

@mUHleee_ @00azula Sure, here’s the video I referred to. There are many bc methods that halt periods altogether. I’ve been on them, myself. There are no negative health consequences from NOT getting your period. https://t.co/2L4eRdsjUn

Aug 8, 2020 · 1,714 followers View post →
yhom torke
@b1mbolino · X

@corpsepary https://t.co/rk8j8nhSJo

Aug 5, 2020 · 1 like · 134 followers View post →
Alan Henness
@zeno001 · X

RT @piekna: @firebird2110 @zaelefty @SciShow And this episode "Why Do People Have Periods When Most Mammals Don't?" that fails to mention w…

Aug 3, 2020 · 3 shares · 8,440 followers View post →
Zachary Elliott
@zaelefty · X

RT @piekna: @firebird2110 @zaelefty @SciShow And this episode "Why Do People Have Periods When Most Mammals Don't?" that fails to mention w…

Aug 3, 2020 · 3 shares · 51,561 followers View post →
A
@piekna · X

@firebird2110 @zaelefty @SciShow And this episode "Why Do People Have Periods When Most Mammals Don't?" that fails to mention women or girls once in its 12 minute running time. https://t.co/bo4bVz7PAn

Aug 3, 2020 · 11 likes · 3 shares · 909 followers View post →
Tynan - Aspiring Research Scientist
@ScienceTynan · X

Why Do People Have Periods When Most Mammals Don't?: https://t.co/1dQk5NXEnI #biology #medicine #Menstruation #reproductivebiology

Jul 20, 2020 · 1 like · 2,367 followers View post →
Puppy eyes
@LaAnawitch · X

@legallyines Hiiii, I'm just gonna leave this here, it's pretty educative and NO, very few mammals actually get periods (menstruation) https://t.co/Ss5nsNNAC0

May 26, 2020 · 444 followers View post →
MiyomiKonran ∞
@MiyomiKonran · X

@inpenem @Mikoaj72606504 Każdego bo taka jest natura zjawiska ciąży u ssaków, nie tylko ludzi :) Jak Pani lubi to proszę bardzo, może Pani mieć biologię tam gdzie światło nie dociera. Jakby jednak interesowało Panią naukowe uzasadnienie to polecam ten film (szczególnie od 6:50): https://t.co/ZAK1MzlqBq

May 14, 2020 · 47 followers View post →
Fernanda Giusti
@fegiusti · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/idYXRWco4y via @YouTube

Apr 28, 2020 · 389 followers View post →
Louisette Lanteigne
@lulex · X

Today my kid was curious to know what other species of animal has a Menstrual flow. The SciShow on YouTube gave a great response to this issue. https://t.co/0kQjeHVOuV

Apr 28, 2020 · 2 likes · 3,331 followers View post →
Never Trump
@Yanggang202013 · X

RT @UBI_NOW: https://t.co/IatcC1sMt7

Apr 18, 2020 · 1 share · 221 followers View post →
UBI_NOW
@UBI_NOW · X

https://t.co/IatcC1sMt7

Apr 18, 2020 · 1 like · 1 share · 11,393 followers View post →
Cecile Braconnier
@braco001 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/glX6V3IdDI via @YouTube

Apr 12, 2020 · 738 followers View post →
Chris O'Donnell
@ChrisOD65316390 · X

Ohhh

Mar 30, 2020 · 138 followers View post →
A
@piekna · X

@SoniaPoulton Amen to that.. Case in point - a 12 minute video about menstruation that fails to mention the word woman or girl https://t.co/kWCDKos24I

Mar 2, 2020 · 6 likes · 909 followers View post →
Djoeke Hannah Vielen
@DjoekeHannah · X

@DaalSanne https://t.co/S2SNWBMc2B

Feb 16, 2020 · 28 followers View post →
Djoeke Hannah Vielen
@DjoekeHannah · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/S2SNWBMc2B via @YouTube

Feb 16, 2020 · 28 followers View post →
A
@piekna · X

Unreal that you can produce a 12 min video about menstruation without mentioning women or girls once! Maybe you should get back to the biology books.. @SciShow @hankgreen Why Do People Have Periods When Most Mammals Don't? https://t.co/2ZFYOuMU1c via @YouTube

Feb 12, 2020 · 909 followers View post →
Ia
@Iyaya007 · X

@animalfess2 Gak... kalo ga dibuahi biasanya penebalan dinding rahimnya akan di reabsorb sama rahim. Kalopun berdarah katanya kucingmu lagi pada masa 'heat' https://t.co/9Ae0U0BPfl

Feb 10, 2020 · 262 followers View post →
Real Skeptic
@RealSceptic · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/a54Fqv7NIa

Feb 9, 2020 · 49 followers View post →
Elise Larsson
@EliseLarsson · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/rzA6y2pYsu via @YouTube

Feb 3, 2020 · 239 followers View post →
Bea Cupin
@beacupin · X

I thought this would put me at ease but nope, I still hate it. https://t.co/W2eDr6NJP7

Jan 30, 2020 · 13,449 followers View post →
Luca
@SorrisoCattivo · X

https://t.co/lovmfaSSol

Jan 29, 2020 · 142 followers View post →
Michael Landau
@MichelLandau · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/5bx3XAv93A via @YouTube

Jan 25, 2020 · 1,388 followers View post →
Juan Pablo Carbajal
@JuanPiCarbajal · X

Why Do People Have Periods When Most Mammals Don't? .. and misogyny https://t.co/EfkfQJ2oco via @YouTube

Jan 25, 2020 · 161 followers View post →
Haley Keller
@haleymkeller · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/nQRiGwS6go

Jan 25, 2020 · 496 followers View post →
Studio RAIN
@r1ms31dk · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/GNgjt5YYxh @YouTubeさんから

Jan 25, 2020 · 165 followers View post →
Sweet Mommee
@Okornore · X

This is really interesting mostly because the process that leads to periods actually protects us from the parasites that are babies. Periods might also be flushing out fetuses that would never survive, before they take too much energy from us https://t.co/k3iutw6e0f

Jan 24, 2020 · 2 likes · 3,211 followers View post →
Magambu Omhle
@Senzi_Ndungane · X

RT @Deus_Ex_Human: Why do humans have periods when most mammals dont? https://t.co/oarKb2MvEG via @SciShow

Jan 24, 2020 · 1 share · 4,272 followers View post →
OP’s Terrifying Answer
@Deus_Ex_Human · X

Why do humans have periods when most mammals dont? https://t.co/oarKb2MvEG via @SciShow

Jan 24, 2020 · 1 like · 1 share · 1,480 followers View post →
Twei Lim Lou
@CommS007 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/O16vaz9g78 via @YouTube

Jan 24, 2020 · 310 followers View post →
David Jameson
@link5261 · X

@KelarRiss Yeah, Aunt Flo isn't nice, but it's kinda just the effect of how humans are set up to start preparing for a baby even before the egg is fertilized, giving them like, 3 days of head-start in case fertilization DOES occur. Topical video: https://t.co/0FWz7aMI4h

Jan 24, 2020 · 238 followers View post →
Santi Patrick Pierini Rees
@SantiPrees · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/iQd5JZqWS2 via @YouTube

Jan 24, 2020 · 1,081 followers View post →
Architeuthis
@fredmanglis · X

https://t.co/UYC0XKl6Vo

Jan 24, 2020 · 199 followers View post →
VeggieBird
@BirdVeggie · X

#TodayILearned The cycling construction & destruction of the female human uterine lining serves as a filtering process to protect the mother (host) from metabolically aggressive fetal aneuploidies that can act like parasites. https://t.co/4NZOxIVqo7 via @YouTube

Jan 23, 2020 · 1 followers View post →
Alnisa Allgood
@allgood2 · X

This is an interesting video. I know I've frequently asked this question, even though I've been incredibly lucky at not having a regular period. 3-4 times a year mostly, sometimes more, but more frequently less. But when I do have one, I'm pretty... https://t.co/fLgP9WbBS8

Jan 23, 2020 · 947 followers View post →
Kairin
@kairin · X

This is actually enlightening. https://t.co/6siaXoSu6m

Jan 23, 2020 · 267 followers View post →
虎猫
@ToraNeko82 · X

RT @SciShow: Most mammals don't menstruate, so why do humans? Scientists have had some bizarre ideas over the centuries, but we seem to fin…

Jan 23, 2020 · 3 shares · 103 followers View post →
David Kopchik
@dkopchik · X

I recommend this @SciShow video: "Why Do People Have Periods When Most Mammals Don't?" As a man, I never knew much about the topic beyond being glad that I didn't get them. Bonus points for being gender neutral when talking about it. https://t.co/FWLXVZjUrX

Jan 23, 2020 · 8 followers View post →
Hogan
@Hogan698 · X

This seems like good information. @DrJenGunter is this accurate? As a man that isn't a doctor or a biologist I don't know much about this subject. https://t.co/SVT6Ux2sW6

Jan 23, 2020 · 2 likes · 6,901 followers View post →
leonmsampaio.bsky.social
@leonmsampaio · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/XFxh68GuZF

Jan 23, 2020 · 242 followers View post →
William Wallace
@bill14051 · X

RT @SciShow: Most mammals don't menstruate, so why do humans? Scientists have had some bizarre ideas over the centuries, but we seem to fin…

Jan 23, 2020 · 3 shares · 361 followers View post →
PAO
@peterandann · X

RT @kevinpbreslin: https://t.co/HXADn0SKZ9

Jan 23, 2020 · 1 share · 4,154 followers View post →
SciShow
@SciShow · X

Most mammals don't menstruate, so why do humans? Scientists have had some bizarre ideas over the centuries, but we seem to finally be getting somewhere. https://t.co/vT0AXVYcPZ https://t.co/SgUNrTqRIY

Jan 23, 2020 · 26 likes · 3 shares · 115,396 followers View post →
Dr. Kevin Breslin|Dr. Caoimhghín Ó Breasláin
@kevinpbreslin · X

https://t.co/HXADn0SKZ9

Jan 23, 2020 · 1 share · 5,830 followers View post →
Suzume
@SuzumeMizuno · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/7PQTZ1WFhv vía @YouTube

Jan 23, 2020 · 568 followers View post →
Delfina
@delfina_1001 · X

Why do we menstruate? https://t.co/5MmI7JPBoA

Jan 23, 2020 · 214 followers View post →
Josh Isuzu
@dukeland99 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/QYTyhMhrth via @YouTube

Jan 23, 2020 · 63 followers View post →
Lang Ya'ko: Isabel
@RosasXOso · X

I am so into the Choosy Uterus Hypothesis for menstruation, miscarriages, and why not all zygotes become fetuses. https://t.co/JTPP1vzJ4I

Jan 23, 2020 · 515 followers View post →
Skywise
@Skywise001 · X

https://t.co/D1LcB6wNkj

Jan 23, 2020 · 7,601 followers View post →
Charles Ikenna
@CharlesIkenna23 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/GLuZlDf5Bu via @YouTube

Jan 23, 2020 · 3,222 followers View post →
waldo.5
@waldo595260466 · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/5sERZWGjAe via @YouTube

Jan 23, 2020 · 6 followers View post →
Francis Luigi Magpantay
@roiji · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/ESg6fGYCG5 via @YouTube

Jan 23, 2020 · 246 followers View post →
skelly
@SuprChrgdBullet · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/v3flel4vfr via @YouTube

Jan 23, 2020 · 38 followers View post →
boysvswomen.com
@boysvswomen · X

.@scishow drinking game rules - 1 sip every time they avoid using male/female Their latest video is on periods: F̶e̶m̶a̶l̶e̶ Humans Menstrators Half of People We/Us Half of humanity Menstrating people People Parent Host Half of us People whose uteruses https://t.co/WFkT0fwsvl

Jan 22, 2020 · 10 likes · 2 shares · 12,049 followers View post →
Jes The Red
@Redsfreaky · X

https://t.co/BNxj9Lfhrg

Jan 22, 2020 · 744 followers View post →
Bishal Ghimire
@bishal_ghimire · X

Why Do People Have Periods When Most Mammals Don't? https://t.co/0WTXm59FUE via @YouTube

Jan 22, 2020 · 961 followers View post →
Eadgyt
@eadgyt1 · X

Important information.. https://t.co/QhgvbcWaDe

Jan 22, 2020 · 3 followers View post →
சுமன்
@TamilsumanB · X

RT @kryes: மனிதப் பெண்களுக்கு மட்டுமே "மாத விலக்கு" ஏன்? ஏவாள் சாபமா?:) சில விலங்குகட்கும் எப்படி? அவையும் ஆப்பிள் தின்னுச்சா?

Dec 19, 2019 · 12 shares · 334 followers View post →
An-Ton
@an10ANTON · X

https://t.co/7Kv5nrf1JV I have always had thought about whether female animals menstruate! Surprisingly some animals do... but not all

May 25, 2019 · 754 followers View post →