A Blue whale's butthole can stretch to approximately 3½ feet fact check
Executive summary
Claims on social posts that a blue whale’s anus can “stretch to approximately 3½ feet” are part of a viral meme ecosystem; scientific reporting cited in Ars Technica and related coverage finds far smaller estimates — around 10–15 centimeters (about 4–6 inches) — based on expert commentary and anatomical inference [1]. Popular memes and novelty posts instead give wildly larger numbers (40 inches, 1 meter, 3.5 feet) but these appear in humor sites and social posts, not in cited scientific reporting [2] [3] [4].
1. Viral memes vs. scientific estimates: the story so far
The “3½ feet” figure appears on social platforms and meme sites as a punchline in a string of jokes comparing whale anatomy to politicians [4] [2]. These posts join other tall claims — e.g., “40 inches” or “up to a meter” — that are clearly presented in humorous or satirical contexts [2] [3]. By contrast, investigative science-oriented coverage collected expert views and concluded the likely size of a blue whale’s anus is much smaller: roughly 10–15 cm (about the size of a large grapefruit) [1].
2. What scientists actually say
Ars Technica summarizes interviews and literature review by researchers such as Dr. Matt Leslie and others who independently estimate a blue whale’s anus at about 10–15 centimeters, and cites marine mammal illustrator Uko Gorter and Dr. Dara Orbach explaining why whale anatomy doesn’t scale simply with body size [1]. Those experts emphasize that diet and anatomy (filter-feeding krill consumers) make enormous anal openings unnecessary [1].
3. Where the large numbers come from
The larger figures circulate through memes, novelty merch, and social postings with no cited peer-reviewed measurement behind them [2] [3] [4]. Historical anatomical plates (an 1828 illustration is mentioned) have been invoked online to suggest larger openings in at least one stranded specimen, but these historical drawings do not substitute for modern anatomical measurement and are discussed as anomalies or curiosities rather than definitive evidence [5] [1].
4. Gaps in the public record and limits of reporting
Available sources show scientists were reluctant to catalog whale anal dimensions historically because it was not of practical interest to whalers or researchers; modern studies rarely focus on absolute anal diameter, so definitive large-scale measurements are scarce [1]. Ars Technica notes that absolute size was “escaped scientific scrutiny for centuries” and that direct documentation is limited [1]. Therefore, while current expert estimates point to a small opening (10–15 cm), comprehensive morphometric surveys specifically measuring anal stretch capacity are not cited in these sources [1].
5. How to interpret contradictory claims
When a claim appears on humor sites or as a meme, it is not equivalent to scientific evidence; the big numbers (3.5 ft, 40 in, 1 m) appear in comedic contexts and lack supporting scientific citation in the provided reporting [2] [3] [4]. The best-available expert commentary collected in the reporting contradicts those meme figures and gives the much smaller 10–15 cm estimate [1].
6. Bottom line for fact-checking
The precise claim “A blue whale’s butthole can stretch to approximately 3½ feet” is sourced to viral meme posts and novelty content [4] [2]. Scientific commentary and anatomy-focused reporting summarized by Ars Technica puts the likely size at roughly 10–15 cm (about 4–6 inches) and notes a lack of systematic measurements in the literature [1]. Given those sources, the 3½-foot figure is unsupported by the cited expert reporting and appears to be misinformation or jokey exaggeration rather than verified anatomical fact [1] [2].
Limitations: reporting cited here relies on journalistic synthesis and expert interviews rather than a comprehensive peer-reviewed morphometric dataset; available sources do not mention a definitive scientific measurement confirming either the meme numbers or an exhaustive alternative measurement [1].