Wikipedia:Reference desk/Archives/Science/2022 April 6

= April 6 =

Hyrax
"Hyraxes are sometimes described as being the closest living relative of the elephant". Can i harvest ivory from the gophers in my garden? Zindor (talk) 00:34, 6 April 2022 (UTC)


 * Our article Ivory is written in a confusing way. It says that "certain" teeth are traded as ivory, but doesn't clearly explain which ones. It also mentions the two canine-like teeth of elk as "ivory teeth", implying that the other teeth are not ivory. In fact those two teeth lack enamel, which is the crucial difference. Hippopotamus teeth, on the other hand, have enamel on one surface, but are still traded as ivory. I'm unclear on whether the enamel is normally removed from hippo ivory. Similarly, the tusks of hyraxes have enamel on the front, but not the back, and as such they are just like a rodent's incisors, including those of a gopher. In principle if you could remove the enamel from a gopher's front teeth you would have produced two tiny scraps of ivory. Possibly any teeth count as ivory, even with a coating of enamel. However, size seems important to commercial value. Card Zero  (talk) 03:50, 6 April 2022 (UTC)


 * Other than being superficially similar looking (perhaps due to convergent evolution), hyraxes are not particularly closely related to gophers. Hyraxes and Gophers only belong to the same infraclass, being Placentalia, hyraxes belong to superorder Afrotheria of magnorder Atlantogenata, while gophers belong to superorder Euarchontoglires of magnorder Boreoeutheria.  Which is to say that gophers are more closely related to humans (having a more recent common ancestor) than they are to hyraxes.  -- Jayron 32 10:52, 6 April 2022 (UTC)

Osprey hunting behavior
There’s a video currently trending on Insta showing an Osprey diving into the water, grabbing a fish, and then coming out of the water and flying away. One would think their wet feathers would make it difficult to fly back out of the water again. How do they do this? Viriditas (talk) 01:22, 6 April 2022 (UTC)


 * According to birdwatchingpro.com and Osprey Tales, they are oily, producing oil for their feathers from preen glands. Though apparently this effect is removed if an osprey is caught in an oil spill. Feather says that powder down can provide waterproofing, although I don't see that mentioned in relation to ospreys. Not sure why the article on down feathers doesn't mention this function. The Feather article also claims that "The feathers of cormorants soak up water and help to reduce buoyancy, thereby allowing the birds to swim submerged", but Cormorant disagrees with this, pointing out that, like ospreys, they have preen glands, and the truth about cormorants seems mysterious. (Fortunately you didn't ask.) Card Zero  (talk) 02:31, 6 April 2022 (UTC)
 * The swimming action of the fish obviously propels the Osprey back out of the water. The action doesn't occur in Cormorants because they don't hold the fish with talons. Zindor (talk) 02:42, 6 April 2022 (UTC)
 * Obviously? What if the fish is swimming in the other direction when it's caught? Bazza (talk) 10:48, 6 April 2022 (UTC)
 * The articles sarcasm and joke should explain the physics of the situation sufficiently, I believe. -- Jayron 32 11:04, 6 April 2022 (UTC)
 * I understand both, but didn't notice the body language or inflection in the comment. Stranger things have been written here as truth. Bazza (talk) 11:07, 6 April 2022 (UTC)
 * , i would suggest that the osprey only pounces on fish that are surfacing, so facing in the right direction. Zindor (talk) 12:44, 6 April 2022 (UTC)
 * But by what means do waterlogged cormorants take to the air? Card Zero  (talk) 13:31, 6 April 2022 (UTC)
 * If you observe cormorants you will see they leave the water onto an object (small island etc) and stretch their wings out. This dries them off. If they were out at sea i suspect that there is a fair chance they could still take off, having enough water saturation to decrease buoyancy doesn't necessarily mean they couldn't fly, but it would certainly hinder it. Zindor (talk) 14:20, 6 April 2022 (UTC)


 * Flightless cormorants do this too, for some reason. Or for no reason? Card Zero  (talk) 14:40, 6 April 2022 (UTC)
 * Probably just a vestigial or re-purposed fixed action pattern. The wing drying is either a beneficial trait or has no negative effect and they haven't evolved out of it. Zindor (talk) 15:15, 6 April 2022 (UTC)


 * FYI, sometimes their feathers *do* get too wet to get out of the water again, or the fish they caught is too heavy to fly off with - however ospreys can actually swim if the need arises. They do the butterfly stroke with their wings. --Iloveparrots (talk) 11:19, 6 April 2022 (UTC)

How would purple rain originate on an alien planet
What would need to happen for this to happen? — Preceding unsigned comment added by Nexxotic (talk • contribs) 03:17, 6 April 2022 (UTC)
 * You can ask how it would happen on Earth too. It could be due to animal excrement after eating purple grapes. There are not many purple minerals or purple gases that might make purple liquids. My second guess would be on a movie set with artificially dyed rain. Graeme Bartlett (talk) 08:32, 6 April 2022 (UTC)
 * Until he passed, the famous atmospheric scientist Prince Rogers Nelson knew how to do it, but sadly, he took his knowledge to the grave. -- Jayron 32 10:43, 6 April 2022 (UTC)


 * In sufficiently high concentration, permanganate solutions (in water) are intensily pink to purple, a colour known as Fuchsia: . But what natural process would produce the permanganate, and how would it get into the drops? Several manganese minerals such as pyrolusite are common on Earth and therefore also plausibly on planet Prince. Are there naturally occurring carbonates or hydroxides with which it could fuse? --Lambiam 12:40, 6 April 2022 (UTC)
 * Some.Category:Carbonate minerals, Category:Hydroxide minerals. But the with which it could fuse part is beyond my ken. Since permanganates are oxidizing agents, a permanganate thunderstorm could be fun. Card Zero  (talk) 13:44, 6 April 2022 (UTC)
 * Not permanganate, but Mars has a not-insignificant-amount of perchlorate in the soils, perchlorate is also a strong oxidizing agent, and dealing with it is part of the discussion on any sort of serious Mars visit by humans. If Mars had rain, it would not be hard to envision it having some perchlorate in it.  -- Jayron 32 15:54, 6 April 2022 (UTC)


 * Purple alien bacteria. On Earth, see "Schiermeier, Q. 'Rain-making' bacteria found around the world. Nature (2008). Viriditas (talk) 21:55, 6 April 2022 (UTC)
 * Blood rain is typically due to algae spores. So, yeah, some purple alien life could fall from the alien sky, if we assume there is alien life. Card Zero  (talk) 23:37, 6 April 2022 (UTC)
 * Wait it can really rain "blood"? Truth in heavy metal. Sagittarian Milky Way (talk) 01:35, 7 April 2022 (UTC)
 * Charles Fort documented a large number of cases of anomalies; raining blood was one of them. --  Jack of Oz   [pleasantries]  20:01, 7 April 2022 (UTC)


 * Saharan dust episodes intense enough to colour the sky - and occasionally the rain - an orange-brown color are rare enough to make the news but far from unheard of. I can't reallt think of anything which might transform that orange to purple though. — Preceding unsigned comment added by 2A01:E34:EF5E:4640:995C:79C2:9A9B:C3C2 (talk) 11:00, 7 April 2022 (UTC)