Readers ask about bird droppings, Ice Age cave art and more

Bodily waste is cool, truly

Snot bubbles could assist a short-beaked echidna cool off by coating the critter’s nostril with moisture, which evaporates and attracts warmth from a blood-filled sinus, serving to to chill the blood, Elise Cutts reported in “Adorable spike-balls beat the heat with snot bubbles” (SN: 2/11/23, p. 32).

Different animals even have artistic methods of utilizing fluids to remain cool. Some birds, for instance, urinate on themselves to outlive sizzling days, Cutts wrote. Reader James Wilson famous that the phrase “urinate” is perhaps deceptive, since hen waste is often a mixture of urine and feces.

It’s true that hen droppings are a mixture of urine and feces that goes by means of one opening known as the cloaca. So “excrete” is perhaps a extra acceptable time period, says ornithologist Julián Cabello-Vergel of the College of Extremadura in Badajoz, Spain. For birds that cool off by way of waste elimination, a phenomenon known as urohidrosis, the liquid element of hen droppings is vital. When storks, herons, boobies and another kinds of birds excrete extra-juicy waste on their legs, “it’s the evaporation of the water contained within the excreta which produces warmth loss from the [body] to the surroundings,” Cabello-Vergel says.

When gene stream runs afowl

About 20 to 50 p.c of recent jungle fowl DNA comes from domesticated chickens resulting from interbreeding, threatening the genetic range and long-term survival of the wild birds, which reside in South and Southeast Asia, Jake Buehler reported in “Chicken DNA runs amok in wild birds” (SN: 2/11/23, p. 14).

Reader Van Snyder requested if wild jungle fowl switch any of their genetic materials to chickens.

Evolutionary biologist Frank Rheindt has “little question that gene stream between home chickens and wild jungle fowl is bidirectional.” Many free-ranging home village chickens in South and Southeast Asia are most likely recurrently uncovered to genes from wild pink jungle fowl that they encounter close to the boundaries between villages and forests.

However the stream of genetic materials from wild pink jungle fowl to chickens general could be marginal, says Rheindt, of the Nationwide College of Singapore. “The huge world majority of home chickens are battery chickens saved in tight enclosures, principally outdoors tropical Asia, and people chickens would stay unaffected.”

Defining melancholy

Melancholy is commonly blamed on a chemical imbalance within the mind. In actuality, scientists don’t have an amazing clarification of what melancholy is or what causes it, regardless of a long time of analysis, Laura Sanders reported in “No simple answers” (SN: 2/11/23, p. 18).

Many readers expressed their appreciation for Sanders’ reporting.

“It’s a incredible instance of standard science writing for the general public about an pressing and tough problem regarding human struggling,” reader R. Michael Johnson wrote. “I used to be notably impressed and gratified by your a­ssurances that melancholy isn’t one-size-fits-all, and that the geographical/cultural nuances are to not be slighted.”

Why “Y”?

Ice Age hunter-gatherers could have used cave artwork to trace the mating and birthing seasons of native fauna, Anna Gibbs reported in “Ice Age cave art may be a calendar” (SN: 2/11/23, p. 16). For example, “Y” symbols within the artwork may signify start, researchers suspect.

Reader Richard Delaware puzzled why the “Y” image developed that which means.

“We’ll most likely by no means know,” says Ben Bacon, an impartial researcher primarily based in London who helped decipher the cave artwork. One attainable clarification may very well be that the image represents the feminine pubic space. In Paleolithic artwork, together with in small carved collectible figurines and wall work, this space was typically depicted with a pronounced Y-shaped define, Bacon says.

One other attainable interpretation depends on the truth that the image is a line that splits into two. “One turns into two, which describes completely the method of start,” Bacon speculates.


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