How compatible are mammal wombs?

How compatible are mammal wombs?

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I had read about science working towards the creation of artificial wombs however I wonder how compatible are mammal wombs and connected systems to develop fetuses. What species are so compatible that they would be able to surrogate the embryos and fetuses of another species?

In short: Not completely, but more than you would expect.

The project to clone a mammoth considered using an adult female elephant as a surrogate mother, so in theory closely related species can do this.


For example, as a baby is developing hands in the womb , those hands start out with webbing between the fingers.

Most of these genes instruct how our brain circuitry is laid down in the womb , and how it functions.

A group of scientists now suspects part of the reason may be that megalodon ate its siblings while still in its mother’s womb .

So, in the new study, the team suggests that a behavior unique to this order may also play a role — a kind of cannibalism that occurs in the womb .

To the left is what is ostensibly a dining room, where everything is hot pink and it feels like the world’s most chaotic bubble bath, or maybe a very fun womb .

Complete male reproductive independence would also hinge on artificial womb technology, which also made headlines in 2014.

At present, not every woman is young enough, fertile enough, or healthy enough to have a baby using her own eggs or her own womb .

The womb may become artificial by the end of the century but it will still be the battleground for feminist politics.

But when the womb —the most politicized body part in history—is separated from the woman, what will it mean for feminism?

A report says a man-made womb could be reality within 30 years.

Hearken unto me, O house of Jacob, all the remnant of the house of Israel who are carried by my bowels, are borne up by my womb .

For I know that transgressing thou wilt transgress, and I have called thee a transgressor from the womb .

Why came I out of the womb , to see labour and sorrow, and that my days should be spent in confusion?

As for Ephraim, their glory hath flown away like bird from the birth, and from the womb , and from the conception.

Nor is the heat the cause of the black complexion, particularly of children in the womb , who are out of the reach of the sun.

Charismatic mammals can help guide conservation

Formula combines flagship species with lesser-known groups to measure value of hotspots.

Lions, elephants and other charismatic species are not by themselves good indicators of biodiversity hotspots. But a new analysis suggests that studies of tourist-pleasing big mammals can be part of a cocktail of indicators that produce useful maps for conservation planning.

Scientists at conservation organizations often focus their research on large, interesting animals that the public — and donors — love, such as pandas, tigers and gorillas. One rationale is that because many of these 'charismatic megafauna' thrive only in large, rich, biodiverse areas, their distribution can act as a proxy for the diversity of whole ecosystems, from microbes up, which is extremely difficult to measure. Conservationists have argued that actions intended to preserve one iconic animal can have an 'umbrella effect' and save less-glamorous species that thrive in its shadow.

However, some studies have cast serious doubt on the reality of the umbrella effect. A 1998 review 1 by Daniel Simberloff, a biologist now at the University of Tennessee in Knoxville, noted that “whether many other species will really fall under the umbrella is a matter of faith rather than research”. And a report 2 in 2000 found that maps of the ranges of the 'Big Five' African mammals popular with tourists — lions (Panthera leo), leopards (Panthera pardus), elephants (Loxodonta africana), African buffalo (Syncerus caffer) and rhinos (Diceros bicornis and Ceratotherium simum) — were “not significantly better for representing the diversity of mammals and birds than choosing areas at random”.

So Enrico Di Minin and Atte Moilanen, population biologists at the University of Helsinki, decided to construct a formula that would combine the ranges of the Big Five with other information to make truly useful maps. Their analysis appeared on 9 December in Journal of Applied Ecology 3 .

The duo focused on KwaZulu-Natal, a South African province long known to be a biodiversity hotspot, where the Big Five roam among forests, thickets, bushveld and grasslands. The researchers made thousands of maps at 200 × 200 metre resolution using 662 biodiversity measures, each describing the distribution of a habitat type or of a species. They considered species that conservationists care about most: the endangered, the rare and especially the endemic, meaning the plants and animals that live in KwaZulu-Natal and nowhere else.

Di Minin and Moilanen found that the distributions of the Big Five, on their own, did not do a great job of predicting where one might find high biodiversity for other species. In particular, the areas with lots of the charismatic mammals were not necessarily the same places that were rich in invertebrates, reptiles, amphibians or plants.

But the researchers also created maps that overlapped several layers of data, showing the distribution of the Big Five as well as those of key birds, reptiles and amphibians. Moreover, they added a layer of information concerning the diversity of habitat types within each unit of surface area they considered. They found that, for a given amount of land, areas that included as much of this diversity as possible also included a high percentage of the area's plant and invertebrate diversity.

Thus, even in places — and there are many — where data about plants and invertebrates are lacking, information on charismatic megafauna can be useful if it's supplemented by information on additional animal groups and habitat types may be a reasonable surrogate for all the rest of biodiversity, from bugs to trees to molds to microbes.

The “more layers” approach to measurements of biodiversity seems to work in every land- and seascape, says ecological modeller Hugh Possingham of the University of Queensland in Brisbane, Australia. “There are now many surrogacy studies like this one. If you add more layers you get a better result. If you have got more data, use it,” he says.

But why use charismatic megafauna at all, if these species are so bad at predicting where less-alluring biodiversity is found? Di Minin says that a map is more useful when it explicitly includes the economically important large animals. “A big proportion of the tourists visiting South Africa are attracted by the big guys. These guys are generating a lot of cash,” he says. The important question, he adds, is “how can we use them to protect more biodiversity?”



Most male birds (e.g., roosters and turkeys) have a cloaca (also present on the female), but not a penis. Among bird species with a penis are paleognathes (tinamous and ratites) [3] and Anatidae (ducks, geese and swans). [4] A bird penis is different in structure from mammal penises, being an erectile expansion of the cloacal wall and being erected by lymph, not blood. [5] It is usually partially feathered and in some species features spines and brush-like filaments, and in flaccid state curls up inside the cloaca. The lake duck (also called Argentine blue-bill) has the largest penis in relation to body size of all vertebrates while usually about half the body size (20 cm), a specimen with a penis 42.5 cm long is documented.

While most male birds have no external genitalia, male waterfowl (Anatidae) have a phallus. Most birds mate with the males balancing on top of the females and touching cloacas in a "cloacal kiss" this makes forceful insemination very difficult. The phallus that male waterfowl have evolved everts out of their bodies (in a clockwise coil) and aids in inseminating females without their cooperation. [6] The male waterfowl evolution of a phallus to forcefully copulate with females has led to counteradaptations in females in the form of vaginal structures called dead end sacs and clockwise coils. These structures make it harder for males to achieve intromission. The clockwise coils are significant because the male phallus everts out of their body in a counter-clockwise spiral therefore, a clockwise vaginal structure would impede forceful copulation. Studies have shown that the longer a male's phallus is, the more elaborate the vaginal structures were. [6]

The lake duck is notable for possessing, in relation to body length, the longest penis of all vertebrates the penis, which is typically coiled up in flaccid state, can reach about the same length as the animal himself when fully erect, but is more commonly about half the bird's length. [7] [8] It is theorized that the remarkable size of their spiny penises with bristled tips may have evolved in response to competitive pressure in these highly promiscuous birds, removing sperm from previous matings in the manner of a bottle brush. The lake duck has a corkscrew shaped penis. [9]

Male and female emus are similar in appearance, [10] although the male's penis can become visible when it defecates. [11]

The male tinamou has a corkscrew shaped penis, similar to those of the ratites and to the hemipenis of some reptiles. Females have a small phallic organ in the cloaca which becomes larger during the breeding season. [12]


As with any other bodily attribute, the length and girth of the penis can be highly variable between mammals of different species. [13] [14] In many mammals, the size of a flaccid penis is smaller than its erect size.

A bone called the baculum or os penis is present in most mammals but absent in humans, cattle and horses.

In mammals the penis is divided into three parts: [15]

  • Roots (crura): these begin at the caudal border of the pelvic ischial arch. : the part of the penis extending from the roots. : the free end of the penis.

The internal structures of the penis consist mainly of cavernous, erectile tissue, which is a collection of blood sinusoids separated by sheets of connective tissue (trabeculae). Some mammals have a lot of erectile tissue relative to connective tissue, for example horses. Because of this a horse's penis can enlarge more than a bull's penis. The urethra is on the ventral side of the body of the penis. As a general rule, a mammal's penis is proportional to its body size, but this varies greatly between species – even between closely related ones. For example, an adult gorilla's erect penis is about 4.5 cm (1.8 in) in length an adult chimpanzee, significantly smaller (in body size) than a gorilla, has a penis size about double that of the gorilla. In comparison, the human penis is larger than that of any other primate, both in proportion to body size and in absolute terms. [16]

Even-toed ungulates (Artiodactyla)

The penises of even-toed ungulates are curved in an S-shape when not erect. [17] In bulls, rams and boars, the sigmoid flexure of the penis straightens out during erection. [18]

When mating, the tip of a male pronghorn's penis is often the first part to touch the female pronghorn. [19] The pronghorn's penis is about 13 cm (5 in) long, and is shaped like an ice pick. [20] The front of a pronghorn's glans penis is relatively flat, while the back is relatively thick. [21] The male pronghorn usually ejaculates immediately after intromission. [22] [23]

The penis of a dromedary camel is covered by a triangular penile sheath opening backwards, [24] and is about 60 cm (24 in) long. [25] [26] The camelmen often aid the male to enter his penis into the female's vulva, though the male is considered able to do it on his own. Copulation time ranges from 7 to 35 minutes, averaging 11–15 minutes. [27] [28]

Wikimedia Commons has media related to Bull penis .

Bulls have a fibro-elastic penis. Given the small amount of erectile tissue, there is little enlargement after erection. The penis is quite rigid when non-erect, and becomes even more rigid during erection. Protrusion is not affected much by erection, but more by relaxation of the retractor penis muscle and straightening of the sigmoid flexure. [29] [15] [30]

The male genitalia of mouse deer are similar to those of pigs. [31] A boar's penis, which rotates rhythmically during copulation, [32] is about 46 cm (18 in) long, and ejaculates about a pint of semen. [33] Wild boars have a roughly egg-sized sack near the opening of the penis, which collects urine and emits a sharp odour. The purpose of this is not fully understood. [34]

A stag's penis forms an S-shaped curve when it is not erect, and is retracted into its sheath by the retractor penis muscle. [35] Some deer species spray urine on their bodies by urinating from an erect penis. [36] One type of scent-marking behavior in elk is known as "thrash-urination, [37] [38] which typically involves palpitation of the erect penis. [38] [39] [40] A male elk's urethra points upward so that urine is sprayed almost at a right angle to the penis. [38] A sambar stag will mark himself by spraying urine directly in the face with a highly mobile penis, which is often erect during its rutting activities. [41] Red deer stags often have erect penises during combat. [42]


Cetaceans' reproductive organs are located inside the body. Male cetaceans (whales, dolphins, and porpoises) have two slits, the genital groove concealing the penis and one further behind for the anus. [43] [44] [45] [46] Cetaceans have fibroelastic penises, similar to those of Artiodactyla. [47] The tapering tip of the cetacean penis is called the pars intrapraeputialis or terminal cone. [48] The blue whale has the largest penis of any organism on the planet, typically measuring 2.4–3.0 m (8–10 ft). [49] Accurate measurements are difficult to take because its erect length can only be observed during mating, [50] which occurs underwater. The penis on a right whale can be up to 2.7 m (8.9 ft) – the testes, at up to 2 m (6 ft 7 in) in length, 78 cm (2 ft 7 in) in diameter, and weighing up to 238 kg (525 lb), are also by far the largest of any animal on Earth. [51] On at least one occasion, a dolphin towed bathers through the water by hooking his erect penis around them. [52] Between male bottlenose dolphins, homosexual behaviour includes rubbing of genitals against each other, which sometimes leads to the males swimming belly to belly, inserting the penis in the other's genital slit and sometimes anus. [53]

Odd-toed ungulates (Perissodactyla)

Stallions (male horses) have a vascular penis. When non-erect, it is quite flaccid and contained within the prepuce (foreskin, or sheath).

Tapirs have exceptionally long penises relative to their body size. [54] [55] [56] [57] The glans of the Malayan tapir resembles a mushroom, and is similar to the glans of the horse. [58] The penis of the Sumatran rhinoceros contains two lateral lobes and a structure called the processus glandis. [59]


All members of Carnivora (except hyenas) have a baculum. [60] Canine penises have a structure at the base called the bulbus glandis. [61] [62]

During copulation, the spotted hyena inserts his penis through the female's pseudo-penis instead of directly through the vagina, which is blocked by the false scrotum and testes. Once the female retracts her clitoris, the male enters the female by sliding beneath her, an operation facilitated by the penis's upward angle. [63] [64] The pseudo-penis closely resembles the male hyena's penis, but can be distinguished from the male's genitalia by its greater thickness and more rounded glans. [65] In male spotted hyenas, as well as females, the base of the glans is covered with penile spines. [66] [67] [68]

Domestic cats have barbed penises, with about 120–150 one millimeter long backwards-pointing spines. [69] Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which is a trigger for ovulation. Lions also have barbed penises. [70] [71] Male felids urinate backwards by curving the tip of the glans penis backward. [62] [72] When male cheetahs urine-mark their territories, they stand one meter away from a tree or rock surface with the tail raised, pointing the penis either horizontally backward or 60° upward. [73]

The male fossa has an unusually long penis and baculum (penis bone), reaching to between his front legs when erect [74] with backwards-pointing spines along most of its length. [75] The male fossa has scent glands near the penis, with the penile glands emitting a strong odor. [74]

The beech marten's penis is larger than the pine marten's, with the bacula of young beech martens often outsizing those of old pine martens. [76]

Raccoons have penis bones which bend at a 90 degree angle at the tip. [77] The extrusibility of a raccoon's penis can be used to distinguish mature males from immature males. [78] [79]

Male walruses possess the largest penis bones of any land mammal, both in absolute size and relative to body size. [80] [81]

The adult male American mink's penis is 5.6 cm ( 2 + 1 ⁄ 4 in) long, and is covered by a sheath. The baculum is well-developed, being triangular in cross section and curved at the tip. [82]

Copulation by male greater short-nosed fruit bats is dorsoventral and the females lick the shaft or the base of the male's penis, but not the glans which has already penetrated the vagina. While the females do this, the penis is not withdrawn and research has shown a positive relationship between length of the time that the penis is licked and the duration of copulation. Post copulation genital grooming has also been observed. [86]


In Transandinomys talamancae, the outer surface of the penis is mostly covered by small spines, but there is a broad band of nonspinous tissue. [93]

Some features of the accessory glands in the male genital region vary among oryzomyines. In Transandinomys talamancae, [94] a single pair of preputial glands is present at the penis. As is usual for sigmodontines, there are two pairs of ventral prostate glands and a single pair of anterior and dorsal prostate glands. Part of the end of the vesicular gland is irregularly folded, not smooth as in most oryzomyines. [95]

In Pseudoryzomys, the baculum (penis bone) displays large protuberances at the sides. In the cartilaginous part of the baculum, the central digit is smaller than those at the sides. [96]

In Drymoreomys, there are three digits at the tip of the penis, of which the central one is the largest. [97]

In Thomasomys ucucha the glans penis is rounded, short, and small and is superficially divided into left and right halves by a trough at the top and a ridge at the bottom. [98]

The glans penis of a male cape ground squirrel is large with a prominent baculum. [99]

Unlike other squirrel species, red squirrels have long, thin, and narrow penises, without a prominent baculum. [100] [101]

Winkelmann's mouse can easily be distinguished from its close relatives by the shape of its penis, which has a partially corrugated glans. [102]

The foreskin of a capybara is attached to the anus in an unusual way, forming an anogenital invagination. [103]


It has been postulated that the shape of the human penis may have been selected by sperm competition. The shape could have favored displacement of seminal fluids implanted within the female reproductive tract by rival males: the thrusting action which occurs during sexual intercourse can mechanically remove seminal fluid out of the cervix area from a previous mating. [104]

The penile morphology of some types of strepsirrhine primates has provided information about their taxonomy. [105] Male galago species possess very distinctive penile morphology that can be used to classify species. [106] [107] [108]

The adult male of each vervet monkey species has a pale blue scrotum and a red penis, [110] [111] and male proboscis monkeys have a red penis with a black scrotum. [112]

Male baboons and squirrel monkeys sometimes gesture with an erect penis as both a warning of impending danger and a threat to predators. [113] [114] In male squirrel monkeys, this gesture is used for social communication. [115]


The human penis is an external sex organ of male humans. It is a reproductive, intromittent organ that additionally serves as the urinal duct. The main parts are the root of the penis (radix): It is the attached part, consisting of the bulb of penis in the middle and the crus of penis, one on either side of the bulb the body of the penis (corpus) and the epithelium of the penis consists of the shaft skin, the foreskin, and the preputial mucosa on the inside of the foreskin and covering the glans penis.

The human penis is made up of three columns of tissue: two corpora cavernosa lie next to each other on the dorsal side and one corpus spongiosum lies between them on the ventral side. The urethra, which is the last part of the urinary tract, traverses the corpus spongiosum, and its opening, known as the meatus / m iː ˈ eɪ t ə s / , lies on the tip of the glans penis. It is a passage both for urine and for the ejaculation of semen.

In males, the expulsion of urine from the body is done through the penis. The urethra drains the bladder through the prostate gland where it is joined by the ejaculatory duct, and then onward to the penis.

An erection is the stiffening and rising of the penis, which occurs during sexual arousal, though it can also happen in non-sexual situations. Ejaculation is the ejecting of semen from the penis and is usually accompanied by orgasm. A series of muscular contractions delivers semen, containing male gametes known as sperm cells or spermatozoa, from the penis.

The most common form of genital alteration is circumcision, the removal of part or all of the foreskin for various cultural, religious, and more rarely medical reasons. There is controversy surrounding circumcision.

As of 2015 [update] , a systematic review of 15,521 men, and the best research to date on the topic, as the subjects were measured by health professionals, rather than self-measured, has concluded that the average length of an erect human penis is 13.12 cm (5.17 inches) long, while the average circumference of an erect human penis is 11.66 cm (4.59 inches). [116] [117]


Most marsupials, except for the two largest species of kangaroos and marsupial moles [118] (assuming the latter are true marsupials), have a bifurcated penis, separated into two columns, so that the penis has two ends corresponding to the females' two vaginas. [119]


Monotremes and marsupial moles are the only mammals in which the penis is located inside the cloaca. [120] [121]

Male echidnas have a bilaterally symmetrical, rosette-like, four-headed penis. [122] During mating, the heads on one side "shut down" and do not grow in size the other two are used to release semen into the female's two-branched reproductive tract. The heads used are swapped each time the mammal copulates. [123] [124] [125] When not in use, the penis is retracted inside a preputial sac in the cloaca. The male echidna's penis is 7 cm (3 in) long when erect, and its shaft is covered with penile spines. [126] The penis is nearly a quarter of his body length when erect. [127]

Other mammals

Wikimedia Commons has media related to Elephant penis .

An adult elephant has the largest penis of any land animal. [129] [ self-published source? ] An elephant's penis can reach a length of 100 cm (40 in) and a diameter of 16 cm (6 in) at the base. [ citation needed ] It is S-shaped when fully erect and has a Y-shaped orifice. [130] During musth, a male elephant may urinate with his penis still in the sheath, which causes the urine to spray on the hind legs. [131] [132] An elephant's penis is very mobile, being able to move independently of the male's pelvis, [133] and the penis curves forward and upward prior to mounting another elephant. [67]

In giant anteaters, the (retracted) penis and testes are located internally between the rectum and urinary bladder. [134]

Other vertebrates

Male turtles and crocodiles have a penis, while male specimens of the reptile order Squamata have two paired organs called hemipenes. Tuataras must use their cloacae for reproduction. [137] Due to evolutionary convergence, turtle and mammal penises have a similar structure. [138]

In some fish, the gonopodium, andropodium, and claspers are intromittent organs (to introduce sperm into the female) developed from modified fins.


The record for the largest penis size to body size ratio is held by the barnacle. The barnacle's penis can grow to up to forty times its own body length. This enables them to reach the nearest female for fertilization.

A number of invertebrate species have independently evolved the mating technique of traumatic insemination where the penis penetrates the female's abdomen, thereby creating a womb into which it deposits sperm. This has been most fully studied in bed bugs.

Some millipedes have penises. In these species, the penis is simply one or two projections on underneath the third body segment that produce a spermatophore or sperm packet. The act of insemination, however, occurs through specialized legs called gonopods which collect the spermatophore and insert it into the female.


In male insects, the structure analogous to a penis is known as aedeagus. The male copulatory organ of various lower invertebrate animals is often called the cirrus. [ citation needed ]

The lesser water boatman's mating call, generated by rubbing the penis against the abdomen, is the loudest sound, relative to body size, in the animal kingdom. [139]

In 2010, entomologist Charles Linehard described Neotrogla, a new genus of barkflies. Species of this genus have sex-reversed genitalia. Females have penis-like organs called gynosomes that are inserted into vagina-like openings of males during mating. [140] In 2014, a detailed study of the insects reproductive habits led by Kazunori Yoshizawae confirmed that the organ functions similar to a penis – for example, it swells during sexual intercourse – and is used to extract sperm from the male. [141] [142]


The penis in most male Coleoid cephalopods is a long and muscular end of the gonoduct used to transfer spermatophores to a modified arm called a hectocotylus. That, in turn, is used to transfer the spermatophores to the female. In species where the hectocotylus is missing, the penis is long and able to extend beyond the mantle cavity and transfers the spermatophores directly to the female. Deepwater squid have the greatest known penis length relative to body size of all mobile animals, second in the entire animal kingdom only to certain sessile barnacles Penis elongation in Onykia ingens may result in a penis that is as long as the mantle, head and arms combined. [143] [144] Giant squid of the genus Architeuthis are unusual in that they possess both a large penis and modified arm tips, although it is uncertain whether the latter are used for spermatophore transfer. [143]

The word "penis" is taken from the Latin word for "tail". Some derive that from Indo-European *pesnis, and the Greek word πέος = "penis" from Indo-European *pesos. Prior to the adoption of the Latin word in English the penis was referred to as a "yard". The Oxford English Dictionary cites an example of the word yard used in this sense from 1379, [145] and notes that in his Physical Dictionary of 1684, Steven Blankaart defined the word penis as "the Yard, made up of two nervous Bodies, the Channel, Nut, Skin, and Fore-skin, etc." [146] According to Wiktionary, this term meant (among other senses) "rod" or "bar".

As with nearly any aspect of the body involved in sexual or excretory functions, the penis is the subject of many slang words and euphemisms for it, a particularly common and enduring one being "cock". See WikiSaurus:penis for a list of alternative words for penis.

The Latin word "phallus" (from Greek φαλλος) is sometimes used to describe the penis, although "phallus" originally was used to describe representations, pictorial or carved, of the penis. [147]

Pizzles are represented in heraldry, where the adjective pizzled (or vilené [148] ) indicates that part of an animate charge's anatomy, especially if coloured differently.

In-Cell Sensitivity-Enhanced NMR of Intact Living Mammalian Cells

NMR has the resolution and specificity to determine atomic-level protein structures of isotopically-labeled proteins in complex environments and, with the sensitivity gains conferred by dynamic nuclear polarization (DNP), NMR has the sensitivity to detect proteins at their endogenous concentrations. However, DNP sensitivity enhancements are critically dependent on experimental conditions and sample composition. While some of these conditions are theoretically compatible with cellular viability, the effects of others on cellular sample integrity are unknown. Uncertainty about the integrity of cellular samples limits the utility of experimental outputs. Using several measures, we establish conditions that support DNP enhancements that can enable detection of micromolar concentrations of proteins in experimentally tractable times that are compatible with cellular viability. Taken together, we establish DNP assisted MAS NMR as a technique for structural investigations of biomolecules in intact viable cells that can be phenotyped both before and after NMR experiments.

Even from inside their shells and wombs, embryos are listening

It's surprisingly common for developing animals to listen and adapt to the outside world.

Chickens were one of the first animals known to respond to sound as embryos inside eggs. Alison Burrell

More than 50 years ago, researchers found that chickens start to learn the sounds of their mothers’ calls even before hatching. The findings, published in Science in 1967, demonstrated that chicken embryos were somehow listening to the outside world, interpreting and storing that information.

And it’s not just chicken embryos. A wide range of animal embryos pick up on external sounds and vibrations while inside eggs or the womb, according to a new review paper.

“What was really surprising is how common [embryos] using sound is,” says Mylene Mariette, lead study author and behavioral ecologist at Deakin University in Geelong, Australia. “Embryos are not as isolated from the external world as we tend to see them.”

The new research, published in the journal Trends in Ecology and Evolution, looks at studies from across the animal kingdom, from insects to amphibians to mammals, that seem to pick up on sounds or vibrations “prenatally” (before birth or hatching) and respond in some way. One common response to sound is to strategically coordinate, delay, or speed up egg hatching, says Mariette. “All animals that lay eggs seem to be doing that.”

For instance, stink bugs use the sounds of their siblings emerging from their eggs to coordinate simultaneous hatching and tree frogs hatch early in response to sounds from an approaching predator.

But the example that first got Mariette interested in the topic came from her own research on zebra finches. The small, social birds are adapted to life in their desert home of central Australia. To cool down in their hot environment, the finches pant like dogs, producing an audible “heat call”—the hotter it is, the more frequent the panting.

In a 2016 study, Mariette found that frequent heat calls from parents seem to signal to finch embryos that they’re set to enter the world at an especially hot time. The eggs are incubated in a temperature controlled environment under their parent’s bird bottoms, unable to independently detect outside temperature, so the heat calls provide otherwise unknown information to the unhatched babies. That new data seems to translate into long term developmental changes the zebra finch chicks that hatched after exposure to heat calls had different traits, like slower growth, that made them better suited to life at higher temperatures.

The key to translating sound into physical changes lies in the baby bird’s genes. “Any kind of a biological change that’s sustained and alters development is going to involve changes in gene expression,” says David Clayton, a molecular biologist and neuroscientist at Clemson University who studies gene expression changes in adult birds, and is an author on the review study.

These tweaks in gene expression are also known as epigenetic changes. In epigenetic shifts, the actual DNA code remains unchanged, but the effects of those genes are either amplified or silenced by changing the extent to which the DNA gets turned into proteins. It’s the proteins that actually carry out the gene’s functions, so if the molecules that transcribe DNA into proteins (with some steps in between) are stopped, genes are effectively switched on or off.

The question of how embryos can detect sound in the first place is more complicated. The researchers offer one possibility for animals like mammals and birds. Although ears and the part of the brain that interprets sounds aren’t fully formed in an embryo, other developing brain regions, like the amygdala (which is involved in emotion), can play a role in unconscious sound detection and interpretation. Yet not all brains are the same. Insect brains, for example, don’t have an amygdala and are structured completely differently, says Mark Hauber, a behavioral ecologist at the University of Illinois in Urbana-Champaign who authored a related review study in 2018 that focused only on birds.

[Related: This fluorescent turtle embryo is just one of the year’s most captivating photos of tiny stuff]

Previous work in the field has focused mostly on birds and humans because of the shared ability to learn vocal calls. But, Hauber says, this new study demonstrates that “hearing is what matters rather than learning.” If an embryo can detect sound, it can respond.

This ability means that embryos can continually interact with their environment even after being laid as eggs, allowing them to adapt to rapid changes without a physiological connection to their parents. “They can get an update on the environment,” says Mariette, “whether it’s a heat wave or predators, that gives them a lot more information to adjust their development to those specific conditions.”

For mammals and other animals that carry their young internally, an embryo’s ability to interpret sound could combine with internal cues, like maternal stress hormone levels, to link a particular noise with a context, says Mariette. For example, if both a pregnant rat and the embryo inside hear something, and the pregnant rat’s stress hormone level rises, the embryo might start to learn that the sound indicates a threat.

Beyond an individual animal’s development though, embryos responding to sound cues could make some species—like the zebra finches—better prepared to adapt to quick environmental shifts like climate change than previously expected, says Mariette. It might also mean that noise pollution could be even more harmful than previously thought. Research has already shown that noise pollution like traffic sounds hurt animals by boosting their stress and hindering their ability to communicate as juveniles and adults, but that process of interference could be starting even sooner—in the egg or womb.

Finally, the new research poses a challenge to long-held notions in developmental biology about nature versus nurture. It’s previously been accepted that animals are born with certain innate traits, says Wang-chun Liu, a neuroscientist at Colgate University. But if animals begin responding to their environments as embryos, then some innate behaviors could actually be the product of outside conditions. “If this result is really consistent, I think this may have a very big impact on how we think about what is innate behavior and what is learned behavior,” Liu says.

And though Mariette is focused less on this large, looming question than on the chance to study more sound cues, she does say, “when we think about all of the information that [embryos] can get from sounds, it’s changed our perspective of embryonic development quite a lot.”

Is Christianity Compatible With Evolution?

The so-called battle between Christian creationism and Darwinian evolution has been the cornerstone of the argument that religion and science are incompatible. It seems to have become an accepted idea in modern thought: logic or faith, reason or religion, science or God. Those who insist that a person can believe in both science and God are ignored by both sides of the debate. They are seen simultaneously as weak of faith and easily taken in by the &ldquofairy tales&rdquo of organized religion.

The idea that religion and reason are mutually exclusive is a rather recent phenomenon. Many of the most prominent, influential and revolutionary scientists in history were also proud people of faith. This fact, however, is summarily ignored by both the science and faith contingents. Instead, religion-vs-science debates focus on carefully building up the wall that divides faith and science. Many of the most vocal debaters have a vested interest in avoiding the testimonies of people who have successfully married religion and reason.

When it comes to dealing with the question of religion and science, many people who claim that the two are mutually exclusive actually do a decent job of combining the two. Plenty of &ldquopure scientists&rdquo still subconsciously act as if they believe in a higher power and prayer earnestly. Similarly, &ldquopure religionists&rdquo still accept that gravity is caused by the Earth, the solar system orbits around the Sun, all chemicals are made of molecules and atoms, two objects of different size will hit the ground at the same time and that the universe is effectively infinite. These are some of the basic tenets of the hard sciences. The basics of the softer sciences, such as psychology and sociology, are generally accepted as well by these people who claim to reject science and live solely by faith. So, where does the science vs. religion, it&rsquos my way or the highway, mutually exclusive monolithic idea come from?

The biggest sticking point for many people who seek to marry science and faith is biology. More specifically, the problem is Darwin&rsquos famous theory of evolution by means of natural selection. The Big Bang theory certainly gets its detractors, and not even all scientists are satisfied by the reigning theories of how life begun, but nothing has been seen as a wedge between faith and science as much as evolution.

The theory of evolution was proposed by Charles Darwin in his famous book &ldquoOn the Origins of Species&rdquo in 1859. Darwin&rsquos theory was two pronged and posited that all life on Earth was connected and related to each other and that the incredible diversity of life that can be found on Earth was caused by the slow but steady changes wrought in each species through natural selection. Evolution is often summarized as &ldquosurvival of the fittest,&rdquo but that concept is greatly misleading. Evolution is about the ability of a species to grow, reproduce and have offspring that reaches reproductive age and has offspring of their own. As such, a rabbit that was eaten by a fox when it was two years old but still had babies, grandbabies and great-grandbabies would be considered more evolutionarily successful than an elephant that lived to be 70 years old but never reproduced or a tiger that lived to be 30 but only had two cubs, neither of which produced offspring. In this case, the rabbit is more evolutionarily successful because its traits, say especially long ears to help hear predators, were passed down and spread into the gene pool. Over time, those extra-long ears may come to be the norm as rabbits that have shorter ears are eaten before they can reproduce while extra-long eared rabbits survive long enough to have offspring. When the long ears become the norm, it can be said that the species of rabbit has evolved. It has changed from what it once was in order to better fit its environment.

Darwin&rsquos theory of evolution rubbed a number of religious conventions the wrong way almost immediately. Most creation stories, after all, show creatures being created exactly as they are seen in the present day. There is no mention of slow but steady change over millions of years. Genesis, for example, states that God simply made all the creatures that filled the world. There is no mention of amphibians becoming terrestrial creatures or of the descendants of dinosaurs becoming birds. There is also, however, nothing that describes what these first creatures look like. The &ldquobirds&rdquo of Genesis could well have been feathery velociraptors and the &ldquofish&rdquo could have been the early hagfish.

The theory of evolution in general meshes without serious problem into Christianity so long as a person does not interpret the Bible completely literally. If a person accepts that a &ldquoday&rdquo was not necessarily the 24 hour unit of measure that is used today, then there is no reason that God could not have made animals and plants over a &ldquoday&rdquo that spanned millions of years. The Bible also is silent about whether or not the animals encountered by Adam and Eve remained static since their creation. Again, if a &ldquoday&rdquo is longer than 24 hours for God, God&rsquos early designs could have continued to shift and change. They could have evolved.

Evolution proposes that natural selection is based in part on the randomization of genes that occurs during reproduction. Each living organism essentially draws twelve cards from a deck and has to play with those cards for the rest of the game. Christians, however, have long accepted that things that look random are not coincidence at all. Natural selection may appear to be randomized, but God is controlling what genes mix and which do not. He is still watching over His creations. Humans simply cannot perceive it. As Einstein said, &ldquoGod does not play dice.&rdquo

There are a number of Christians who would be willing to accept Darwin&rsquos theory of evolution if it only applied to animals and plants. People do not, however, like that it also applies to human beings. Genesis shows that God created Adam and Eve just like all the other animals. Adam and Eve shortly begin to speak and act like modern humans. &ldquoShortly,&rdquo however, brings up the question of how long each moment in the creation story really takes. If the Bible is not interpreted literally, those moments between the creation of humans and their speech could be the centuries required for Homo sapiens to develop verbal language.

The compatibility of evolution with Christianity truly depends on how literally a Christian interprets the Bible. Someone who keeps to a strict, purely literal interpretation will not be able to mesh the millennia required for evolution to work with the week-long creation of the universe described in Genesis. A person who takes a slightly more metaphorical stance, however, could easily interpret the days of creation as taking millions if not billions of years each. This would allow for a person to believe in both Darwin&rsquos science and the Bible&rsquos religion and so break down one of the most stubborn barriers in modern thought: that of an us vs. them mentality when it comes to science and religion.

Fluid-filled ‘biobag’ allows premature lambs to develop outside the womb

Overcoming engineering, biology, and technology obstacles, a team of researchers has crafted what may be the best artificial womb yet: a fluid-filled bag in which lambs born early can live for up to 4 weeks, before being ushered into the outside world. Although others have designed similar systems that are still in animal testing, this one is notable for its stripped-down simplicity.

The result is a sealed “biobag” with one tube supplying artificial amniotic fluid and another draining it out. Although some lambs experienced complications, and human testing is, at best, several years off, the advance is generating excitement among those who care for pregnant women and their extremely premature babies.

“What they’ve got is a system where the fetus is really existing very much as it would in the mother’s womb,” says Anna David, a maternal-fetal medicine specialist at University College London (UCL). “The fetus knows what to do,” she adds, noting that as best they could, the physicians stepped aside and ceded control.

Fetuses are in a unique environment before birth. The placenta provides nutrients and oxygen, and the fetus’s lungs do not breathe air. They float in amniotic fluid, which is swallowed by the fetus and created by fetal urination each day, the amniotic fluid “turns over” in this way. For babies that enter the world extremely early—as about 90,000 in the United States and Europe do each year—the prognosis can be grim, with survival ranging from 10% to 50%, and high rates of brain damage, lung disease, and other serious complications.

One of the biggest challenges is that the very technology that saves some of these premature babies, such as mechanical ventilation, also hurts them, for example by damaging their fragile lungs or halting lung development. In the past, researchers have tried to develop artificial wombs that mimic the prebirth environment, but these, too, have been intervention-heavy. In particular, they’ve relied on external pumps to push blood through an oxygenator circuit for gas exchange, which in turn can cause imbalances in fetal blood flow and lead to heart failure.

In the new study, reported today in Nature Communications , researchers at the Children’s Hospital of Philadelphia (CHOP) in Pennsylvania went through several iterations before hitting on technology that largely worked. Their final subjects were eight lambs delivered by cesarean section at about 110 days gestation—the equivalent of 23 or 24 weeks in humans, which is at the edge of viability.

The CHOP team, headed by fetal and pediatric surgeon Alan Flake, began with a high-tech version of a dumpster dive: collecting components doctors at the hospital no longer needed from a system called extracorporeal membrane oxygenation (ECMO). ECMO oxygenates the blood of critically ill infants and children.

For their first try, Flake’s group delivered several lambs shortly before they should have been born. The researchers bathed the lambs in artificial amniotic fluid, with electrolytes that mimicked the real thing, and connected the animals to an oxygenator. The goal was to see whether the system could sustain the lambs. The strategy worked unexpectedly well, with one animal surviving 108 hours, but sepsis and other complications made clear it wasn’t good enough.

Over months, Flake, along with fetal physiologist Marcus Davey, research fellow and surgeon Emily Partridge, and their colleagues kept tinkering. What they ended up with closely mimics biology: an approach that exchanges amniotic fluid rather than recirculating it, a sealed system to keep the outside world at bay, and a pumpless circuit for oxygenation of the blood that’s connected to the lamb fetus through the umbilical cord. The fetus’s heart drives circulation, which keeps blood pressure and other markers at normal levels.

After 4 weeks—the planned length of the experiment—the prematurely delivered lambs were taken off the system and put on artificial ventilators. By and large they did well, though with some modest complications including lung inflammation. Most were sacrificed for further study of how the artificial womb had influenced their development, but some were bottle-weaned, with the longest survivor now more than a year out. Flake is working with U.S. Food and Drug Administration to design an animal trial in accordance with the agency’s standards he estimates that human testing is at least 3 years off.

If the new technology conjures up visions of The Matrix, with fields of fetuses growing in artificial wombs, Flake says that he’s not in the science fiction business: His goal is to help premature infants already being born, not push the limits of viability even earlier. “You go earlier [and] you’re very likely, in my mind, to open a can of worms,” he says. In part that’s because the system is just not designed to support even younger fetuses whose organs are more underdeveloped. Plus, trying to help them risks creating survivors with a poor quality of life—exactly the outcome Flake wants to avoid.

Experts are encouraged by the study. “This is just a much lower stress environment to support” the growth of premature babies than what’s offered now, says Tippi Mackenzie, a fetal and pediatric surgeon at the University of California, San Francisco, who trained with Flake but was not involved in the work.

There remain many uncertainties. One, Mackenzie says, is how fetuses battling an infection will fare in an artificial womb infection is a common driver of preterm birth. Another is the long-term impact of an entirely new approach to caring for these babies. A clinical trial should closely track babies for some time, ideally a couple years, to assess how the system compares to the standard of care—not just in terms of survival, but in lingering health problems extremely premature babies can experience, says Neil Marlow, a neonatologist at UCL.

Despite the unknowns, “If it works, we should get on with it,” says Marlow, who like others agrees that the current setup for these children is far from ideal. “I think it’s just going to revolutionize [neonatal] care,” Mackenzie adds. “I don’t think that’s too much to say.”

Mixing human and animal biology is perceived as being unnatural

But in biology, at least, there is no actual essence to anything in this sense. We’re all made of different combinations of the same kinds of stuff, like proteins and amino acids. Even much of the blueprint – our genes and DNA – are shared across species, such that humans and mice share around 90% of their DNA, and we even share around 35% of our genes with the simple roundworm.

But this does not mean that we don’t often rely on this way of thinking to understand what makes a tiger natural in a way that a chair is not. It is also this intuition that makes us squirm at the thought of a tiger-goat but intrigued by the idea of a chair-table.

The manticore is an example of a human/animal hybrid from medieval bestiaries (Credit: Science Photo Library)

Mixing human and animal biology is perceived as being unnatural and bit on the nose (much like a laksa risotto I once ordered), creating an irrational fear that human-pigs might escape the lab and take over the world (much like I fear the meteoric rise of Italian-Malay cuisine).

While the possibility of human-pig chimera wandering the planet is far from reality, just like the Greeks, our fear of hybrids fosters the sense that such creatures would be monstrous.

Fantastically Wrong: The Theory of the Wandering Wombs That Drove Women to Madness

To revist this article, visit My Profile, then View saved stories.

To revist this article, visit My Profile, then View saved stories.

I don’t have a womb, but I know women who do. All the time, they say to me, “Sorry that I’m out of sorts, my womb just started moving around my torso yesterday!” I tell them that they should probably see a doctor--or at least a sorcerer--immediately.

Fantastically WrongIt's OK to be wrong, even fantastically so. Because when it comes to understanding our world, mistakes mean progress. From folklore to pure science, these are history’s most bizarre theories.Sounds crazy, but in Ancient Greece, this conversation would have actually come up frequently, only it would have been in Greek instead of English. You see, for the Greeks, there was no ailment more dangerous for a woman than her womb spontaneously wandering around her abdominal cavity. It was an ailment that none other than the great philosopher Plato, as well as Hippocrates, the father of modern medicine, described at length.

Greek physicians were positively obsessed with the womb. For them, it was the key to explaining why women were so different from men, both physically and mentally. For Hippocrates and his followers, these differences could be explained by a “wandering womb.” The physician Aretaeus of Cappadocia went so far as to consider the womb “an animal within an animal,” an organ that “moved of itself hither and thither in the flanks.”

The womb could head upward and downward, and left and right to collide with the liver or spleen--movements, argued Aretaeus, that manifest as various maladies in women. If it moved up, for instance, the womb caused sluggishness, lack of strength, and vertigo, “and the woman is pained in the veins on each side of the head.” Should the womb descend, there would be a “strong sense of choking, loss of speech and sensibility” and, most dramatically, “a very sudden incredible death.”

National Library of Medicine

Luckily, the womb had a weakness. “It delights also in fragrant smells,” Aretaeus added, “and advances towards them and it has an aversion to foetid smells, and flees from them.” And yeah, you guessed it: To cure a wandering womb, physicians could lure it back into position with pleasant scents applied to the vagina, or drive it away from the upper body and back down where it belongs by having the afflicted sniff foul scents.

There was a Greek dissenter, though, by the name of Soranus. This physician, writes Helen King in her essay "Once Upon a Text: Hysteria From Hippocrates," argued that the womb was not mobile, and that the success of scent therapies was not due to an animalistic organ reacting violently to odors, but to such aromas causing relaxation or constriction of muscles.

How men could get all of the symptoms of a wandering womb--the headaches and vertigo and, of course, very sudden incredible death--without owning an actual womb, is quite problematic for the theory. But for the Greeks, the womb was clearly the seat of a woman’s wily ways, and very much a weakness (Aristotle held that a woman was a “deformed” or “mutilated” male). The womb was a rather more intimate version of the Achilles’ heel, if you will.

And how’s this for a shocker: The looming threat of a wandering womb was used to assert power over women, argues King. One prescription, for example, was for women to be pregnant as often as possible to keep the ostensibly bored womb occupied, and therefore in its rightful place. Physicians would also prescribe consistent sex.

The Romans, thankfully, distanced themselves from the notion of a truly wandering womb, with the physician Galen noting that while it may seem to be moving, it’s actually the tension of the membranes that hold it in place that pull it up slightly. The problem, he claimed, was the “suffocation” of the womb by a buildup of menstrual blood or, even worse, the female version of “seed” that mixed with male sperm. Retained seed would proceed to rot and produce vapors that corrupt the other organs.

After the fall of the Roman Empire, a Byzantine physician by the name of Paul of Aegina proposed an imaginative cure: Make the lady sneeze and, no joke, shout at her. And when the original Greek writings on womb movement, the Gynaikeia, eventually trickled into the Islamic world, physicians there adopted both Aretaeus’ concept of a wandering organ and also rolled in Galen’s idea of suffocation, greatly expanding on the causes of, and cures for, malignant womb vapors.

All of this knowledge, and I use that term loosely, arrived in Italy in the 12th century, and for the next several hundred years, much emphasis was put on scent therapy and sneezing (hey, sneezing may stop your heart, but it does wonders for the womb--OK, sneezing doesn’t actually stop your heart, and it does nothing for the womb). And by the 1500s, argues King, “the hysteria tradition was complete.” While wombs were no longer thought to wander, they were very much to blame for the ostensible irrationality of women. Over the course of several thousand years, the womb had become less and less of a way to explain physical ailments, and more and more of a way to explain psychological dysfunction.

Watch the video: Outtakes. Best Of - Knallerfrauen mit Martina Hill (September 2022).


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