Well, EB article you linked doesn’t state directly that fatty acids are made out of carbon atoms linked via hydrogen bonds. It has two sentences relevant to the topic, and I am not entirely sure how to parse them:
Unsaturated fat, a fatty acid in which the hydrocarbon molecules have two carbons that share double or triple bond(s) and are therefore not completely saturated with hydrogen atoms. Due to the decreased saturation with hydrogen bonds, the structures are weaker and are, therefore, typically liquid (oil) at room temperature.
The first sentence is (almost)[1] correct.
The second sentence, if viewed without the first one, may technically also be correct, but for what I know it’s not and also it’s not what they meant. See, fatty acids are capable of forming actual hydrogen bonds with each other with their “acid” parts (attached the picture from my organic chem course). On the left covalent bonds are shown with solid lines and hydrogen bonds are shown with dashed lines. The “fatty” part of the molecule is hidden under the letter R. On the right there is methyl instead of R (ie it’s vinegar) and hydrogen bonds are not shown—molecules are just oriented in the right way. (I’m really sorry if I’m overexplaining, I just want to make it understandable for people with different backgrounds).
So, if interpreted literally, the second sentence states that unsaturated fatty acids form less hydrogen bonds with each other for whatever reason, and that’s why they are liquid instead of solid. The explanation I’ve heard many times is different, it says that they are liquid because their “fatty” part is bent because double bonds have different geometry, so it is harder for them to form a crystal. I mean, it is still possible that they also form less hydrogen bonds, but I bet it’s insignificant even if true.
But it honestly looks like they don’t mean all of that at all, they are just incorrectly calling covalent bonds between carbon and hydrogen “hydrogen bonds” and they also don’t know what they mean by “the structures are weaker”. It’s still a sin, but not the one you are accusing them of.
I am also completely fine with the phrasing that is currently in the article and I’m sorry for wasting your time with all that overthinking, hope it wasn’t totally useless.
- ^
The “fatty” part of a fatty acid molecule can’t be called a “hydrocarbon molecule” since it is, well, a part of another molecule, and should rather be called “hydrocarbyl group” (see eg Wikipedia). Also the article should say “at least two carbons” instead of “two carbons” because, as this post is well aware, there exist polyunsaturated fatty acids.
Well, here ya go. Apparently, the mirror-test shrimp are Myrmica ants.
The article is named Are Ants (Hymenoptera, Formicidae) capable of self recognition? (the abstract could’ve been “Yes” if the authors were fond of brevity). https://www.journalofscience.net/html/MjY4a2FsYWk=. Here is the link to download a pdf: https://www.journalofscience.net/downnloadrequest/MjY2a2FsYWk=.
I remember hearing a claim that the mirror test success rate reported in this article is the highest among all animals ever tested, but this needs checking, can easily be false.
This is quite an extraordinary claim published in a terrible journal. I’m not sure how seriously I should take the results, but as far as I know nobody took them seriously enough to reproduce, which is a shame. I might do it one day.
Also, from experience of just observing some ants in the wild and in captivity, Myrmica seem really dumb compared to most of Formicinae, especially something like Oecophylla. I’m a bit surprised that the authors decided to go with them to try and prove ant intelligence.