Tag: Animals

Scientists Produce Healthy Mice Born To Same-Sex Parents Using Stem Cells And Gene Editing

Scientists have been able to breed mice with same-sex parents using a breakthrough technique involving stem cells and gene editing.

Researchers at the Chinese Academy of Sciences have produced healthy mice with two mothers, who were then able to go on to reproduce themselves.

Mice with two fathers were also born during the study, but only survived for a matter of hours.

Using female same-sex parents, the scientists were able to produce a total of 29 live mice from 210 embryos.

All these offspring were normal, lived to adulthood, and were able to give birth to offspring of their own.

The study, published in scientific journal Cell Stem Cell, examined why same-sex mammals are not typically able to reproduce, suggesting stem cells and targeted gene editing can make the process easier.

We were interested in the question of why mammals can only undergo sexual reproduction,” the study’s co-senior author Dr Qi Zhou said.

We have made several findings in the past by combining reproduction and regeneration, so we tried to find out whether more normal mice with two female parents, or even mice with two male parents, could be produced using haploid embryonic stem cells with gene deletions.




While some species of reptiles, amphibians and fish can change gender in order to reproduce or exist as both male and female at the same time, same-sex reproduction for mammals is a more difficult proposition, Dr Zhou said.

He said in mammals, certain maternal or paternal genes are shut off during the development of sperm and egg cells, meaning offspring that do not receive genetic material from both a mother and father might experience developmental abnormalities.

By deleting imprinted genes from immature eggs, researchers have in the past been able to produce mice with two mothers, although most still displayed genetic defects.

To produce healthy bi-maternal mice, Dr Zhou, his co-senior authors Dr Baoyang Hu and Dr Wei Li, and their colleagues used haploid embryonic stem cells (ESCs), containing half the normal number of chromosomes and DNA from each parent.

We found in this study that haploid ESCs were more similar to primordial germ cells, the precursors of eggs and sperm,” Dr Hu said. “The genomic imprinting that’s found in gametes was ‘erased’.

Alongside the 29 healthy mice produced by same-sex female parents, a dozen mice were also born to two male parents during the course of the study.

However, the process of creating mice from same-sex male parents, which involves modifying a larger amounts of genes and inserting fertilised embryos into surrogate mothers, is more complicated.

All offspring from two males born during the study died after less than 48 hours, although scientists believe they can improve the process in future tests.

This research shows us what’s possible,” Dr Li said. “We saw that the defects in bi-maternal mice can be eliminated and that bi-paternal reproduction barriers in mammals can also be crossed through imprinting modification.

We also revealed some of the most important imprinted regions that hinder the development of mice with same-sex parents, which are also interesting for studying genomic imprinting and animal cloning.

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Pollution Is Turning Sea Snakes Black For A Surprising Reason

The turtle-headed sea snake usually sports beautiful bands of alternating black and white. But for decades, researchers have been puzzled by populations living near Pacific Ocean cities that seem to have lost their stripes.

Now a new study may finally have an answer: The pigment in black skin may help city snakes rid themselves of industrial pollutants.

By collecting shed skin from turtle-headed sea snakes in a variety of habitats, scientists discovered that all-black, urban snakes had higher concentrations of trace elements such as arsenic and zinc than did snakes far from cities.

Importantly, the team found the same phenomenon in skin samples from another black-and-white banded snake, the sea krait.




Finally, the scientists observed all-black sea snakes shed their skins more frequently than their rural counterparts, supporting the idea that the darker color allows reptiles to withstand the stresses of city life.

Snake populations are declining worldwide due to human activities, so it is good news that one species evolved a way to resist to pollution,” says study leader Claire Goiran, a marine biologist at the University of New Caledonia and the LabEx Corail.

If the researchers’ findings are correct, the turtle-headed sea snake would join a short list of animals that show “industrial melanism.”

The most famous example is the United Kingdom’s peppered moth, which evolved a darker color to stay camouflaged in forests blackened by coal pollution.

But it was another color-changing animal that made Goiran suspect industrial melanism in turtle-headed sea snakes: She read a paper by University of Warsaw biologist Marion Chatelain that found Parisian pigeons with darker feathers were better able to store toxins than their light feathered counterparts.

What’s more, the pigment that makes feathers (and skin) dark, called melanin, has a tendency to bind to metal ions, which means that growing darker feathers can actually serve as a way for birds to expel toxins from their bodies.

Home to around 100,000 people and a nickel metallurgical plant, Nouméa and its surrounding waters contain both urban and industrial pollution, she says. Goiran suspects the snakes absorb the toxins via the fish that they eat.

Chatelain called the new study interesting, as it’s likely the first to demonstrate a link between darker colorations and metal concentrations in a reptile.

For instance, the study analyzed the metal content between dark and light bands on sea kraits, not turtle-headed sea snakes.

The authors hypothesize that the same trends hold true for the turtle-headed species— but to know this, Chatelain says, skin samples from both colorations of the species from an urban area are required.

Therein lies the problem: It’s almost impossible to find a striped turtle-headed sea snake in an urban area these days, says Goiran.

In Nouméa, as few as 5 percent of the turtle-headed snakes still have their stripes, she says. What’s more, the species only sheds its skin three to four times a year, reducing the odds a researcher will find a sample.

On the other hand, sea kraits shed their skins on land, so they’re much easier to collect.

The study is not finished yet,” Goiran says. “We have many more things to learn from sea snakes.

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Some Ants Are Not As Industrious As You Think. Meet The Lazy Ants!

LAZY ANT

Ants are thought to be industrious and efficient, with everyone in the colony working really hard. However, that might not be as true as once thought.

Some species of ants were actually found to have what’s called lazy ants in their colonies and scientists are baffled!

In 2015, a group of ants called Temnothorax rugatulus are labelled as lazy. This species of ants build their colonies under rocks in the lands of western North America.




Daniel Charbonneau and Anna Dornhaus at the University of Arizona think that these lazy ants are old. They noticed that these lazy ants seem to do nothing–nothing at all.

However, when observed keenly, they found that these “lazy” ants aren’t actually as useless as they thought; their behaviors are just different from other ants.

These ants walk more slowly, are isolated in colony interaction networks and have the smallest behavioural repertoires,” he says.

These lazy ants aren’t necessarily old as they’ve once assumed, they just seem to be immature workers.

LAZY ANT

Their appearances are different too, with plumper bodies and usually having egg cells inside them. Researchers hypothesized that this might their way of storing food–putting it inside them to share with other ants later.

Inactive workers storing food for the colony,” he says. It could also be that the eggs inside them are the food for their brothers and sisters, since there are other species of ants that lay unfertilized edible eggs. However, what this laziness for is still uncertain.

LAZY ANT

As the authors state, there very likely is not just one reason for these inactive ants,” Erik Frank at the University of Würzburg in Germany says. “They probably have various benefits for the colony and reasons for their inactivity.

The researchers are now looking into other ant species to see if lazy ants exist on other types. “The next thing is really starting to look at the function and explanation for inactivity across species to see if there’s some main mechanism which facilitates inactivity,” Charbonneau says.

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This 24ft Long Crocodile That Had Razor Sharp Teeth Was A Top Land Predator In Madagascar Million Years Ago

Razanandrongobe sakalavae

A new study has finally shed light on a mysterious, jaw fragment discovered on Madagascar years ago. It is from an ancient crocodile, nearly 24-feet in length, with teeth like a Tyrannosaurus Rex.

The study, published in the journal PeerJ, highlights the creature, identified as Razanandrongobe sakalavae, as an enormous crocodile ancestor. The ancient croc likely walked on land, hunting its prey with its massive teeth and jaws.




Put together by researchers Cristiano Dal Sasso , Giovanni Pasini, Guillaume Fleury and Simone Maganuco , the study notes that the teeth are “remarkably large, even larger than the largest denticles in large-bodied theropods.

The longest tooth found was 15 cm (5.9 inches) in length. By comparison, the longest T. rex tooth ever found was 12 inches, though they often vary in length.

Razanandrongobe sakalavae

R. sakalavae means “giant lizard ancestor from Sakalava region.”

“Razanandrongobe sakalavae is the largest terrestrial carnivore from this Middle Jurassic terrestrial ecosystem and was perhaps one of the top predators in Madagascar at the time,” the study’s conclusion reads.

“Its jaws were extremely robust and high, but possibly short, and bore large teeth with serrated edges resembling those of theropod dinosaurs. Many features of this species strongly suggest that it fed also on hard tissue such as bone and tendon.”

Razanandrongobe sakalavae

It is the oldest and largest known “notosuchian,” a suborder of Gondwanan mesoeucrocodylian crocodylomorphs that lived during the Jurassic and Cretaceous periods. It predates other members of the species by 42 million years.

The fossils are from the mid-Jurassic period, approximately 166 million years ago. They were first found in the early 1970s, with other parts of the Razana skull found later.

The findings were made after the fossils were made available to the Muséum d’Histoire Naturelle in Toulouse, France, where they were then analyzed and reconstructed. They had been previously part of a private collection.

jaw

The skull was reconstructed using a CT scan, as well as using 3-D printers to print out missing bone fragments, using mirror images of existing fragments.

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Fire Ants Can Build Roiling Ant Towers To Get Around

fire ants

Ants don’t just build complicated nests. They’ll use their own bodies to make things, too. Researchers at Georgia Tech University are studying how the insects link together to make ant rafts and ant bridges.

Now, they’ve accidentally found that fire ants can also get around by using themselves to constantly build and rebuild a moving tower.




Researchers filmed fire ants climbing on top of each other and left the cameras rolling. When they watched the sped-up footage, they found the ant structure sinks under its own weight, so the insects constantly renewed the tower until they went where they wanted to go.

They fed ants radioactive food and watched them build towers in an X-ray machine so they could watch the interior of the tower sink as it grew. Ants that got pushed to the bottom eventually disengaged and started climbing again.

Behavior like this serves a purpose: Fire ants in their natural habitat in Brazil have to deal with frequent flooding. Rafts and towers are a way to escape water and relocate to a new home.

fire ants

It’s worked so well it’s kept ants alive for millions of years all over the world — and in Georgia Tech’s buildings, where they’ve been known to escape labs and set up camps under staffers’ desks.

nd designs based in biology could make our own construction more efficient. Scientists think ant building-techniques like this replenishing trick could be useful for self-assembling robots in the future.

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Bats Have A Vertical “Blind Spot” When Using Echolocation

Bats are well known for their sophisticated use of sound waves and echoes to navigate through areas riddled with obstacles, but now a new study reveals that their use of echolocation can be hindered in the face of smooth vertical surfaces.

The results, published in the September 8 issue of Science, may help explain why injured or dead bats are often found near buildings.

To navigate through the dark, bats rely heavily on echolocation, where they emit high-frequency sounds and use the returning echoes to detect and classify objects in their environment.




However, when Stefan Greif of Eötvös Loránd University was studying how bats use echolocation to recognize water surfaces, he noticed something odd.

I found that bats sometimes collided with our smooth plate when I temporarily positioned it [vertically along] the wall [while] rearranging the setup,” he explained.

That made me wonder why and how those bats would perceive this unusual situation. After my attention was focused on this issue, I started to notice bats sometimes bumping into a metal information plate at the entrance of a cave where we caught bats.

Furthermore, several observations of bats colliding with smooth vertical surfaces (such as glass windows) suggest that bats have problems recognizing them.

Very few smooth vertical surfaces occur naturally in the wild, with objects such as trees and rocks exhibiting rough and uneven surfaces; however, bats do encounter smooth horizontal surfaces in the form of water.

To explore this issue in greater detail, Greif and his colleague Sándor Zsebők monitored greater mouse-eared bats     ( Myotis myotis) as the animals flew through a continuous, rectangular flight tunnel in the dark.

In the corner of the dark tunnel, the researchers placed a metal plate either vertically or horizontally.

Of 21 individual bats, 19 collided with the vertical plate at least once (on average, colliding in 23% of passes) but never with the horizontal plate.

The researchers found that when the bats collided with the vertical plate, they were producing fewer calls, spending less time in front of the plate, approaching the plate at a more acute angle, and had higher flight speeds relative to the bats that avoided collision.

The authors report similar findings in field experiments outside of caves of three different bat species.

It is surprising and intriguing how under certain circumstances even the most sophisticated sensory systems can be tricked into misinterpretation of its environment,” said Greif.

Now that scientists are aware of this sensory loophole for bats during navigation, he noted, they need to gather reliable data about the regular occurrence and extent of these collisions in natural settings.

In ‘high-risk’ areas, like the vicinity of important bat roosts, we should try to avoid setting up unnecessary smooth, vertical surfaces.

In areas where surfaces like extended glass fronts [exist], we should experiment with mitigation tools like acoustic bat deterrents. These emit ultrasonic sounds, inaudible to humans, that are supposed to repel bats.

Even if that fails and curious bats would check on those sounds, they would be very attentive and hopefully realize the obstacles in their way,” said Greif.

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We Decode The Secret Language Of Birds

When we talk about birdsong, we cannot simply refer to a single “voice”. It is a great chorus of complex sounds, it is a real language in itself.

The dry “teak” of a sparrow, the plaintive “gheck gheck gheck” of a woodpecker, the shrill “chirrip” of a lark – each sound has its own purpose and is used in very specific circumstances.

For birdwatchers, learning how to ‘decode’ the secret language of birds is a great way to identify different species and to better understand their behaviour.

The language of birds

Just as vowels and consonants provide the foundation for our words and sentences, birds produce a series of calls, songs and melodies in a ‘language’ so nuanced it could rival our very own alphabet!

This is all thanks to a special vocal organ called the syrinx – the size of a pea, it sits at the junction of the trachea and the bronchi in the lungs.

Its structure – which varies with each species – makes such different songs and sounds possible.

Each sound has a different purpose and this, in turn, makes it possible for birds to communicate with each other in different circumstances.




The warning calls

These involve sharp and penetrating sounds – warning signals used by birds whenever they feel threatened and want to warn companions of danger.

They are usually short sounds strong enough to be heard at great distances. The same sound is often used by predatory birds as part of their attack.

The cries for help

Mom Mom Mom!” Just as children call for their mother with arms outstretched, small birds emit little moans and chirps to attract their mother’s attention, often flapping their wings for good measure.

The call intensity is low, but it can still be clearly perceived in the vicinity of a nest. Small birds frequently continue to use these calls after leaving the nest too – because mom is always mom!

The contact calls

Hey, are you all right?” Contact calls for birds are more or less the equivalent of us making sure a friend is ok.

They use contact calls when they travel in flocks, want to call each other or even just share news about a good food source.

These calls are characterised by moderately strong chirps, similar to a “hum” but not as penetrating as the warning calls.

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Stew From A Polar Bear Liver Will Kill You In A Most Gruesome Way

Liver has long been a staple in many diets. Deep-fried chicken livers are a favorite in parts of the American South. Travel to Germany and you can feast on traditional liverwurst.

In Japan, you can order a heaping helping of sashimi made with raw fish liver. As delicious (or disgusting) as some of these dishes may sound to you, not every bird, fish or mammal necessarily offers the best ingredients for a culinary masterpiece.

In fact, if you ever have the chance to try polar bear liver, think twice — it may be the last meal you ever eat.

The native peoples of the Arctic have never shied away from cooking up some polar bear stew, but they’ve long known to avoid eating the livers of various arctic creatures.




Western explorers, however, learned the hard way. As early as 1596, explorers returned to Europe with accounts of horrible illnesses resulting from the consumption of polar bear liver.

Illness severity depended on how much liver the explorers consumed, but symptoms typically included drowsiness, sluggishness, irritability, severe headache, bone pain, blurred vision and vomiting.

Perhaps the most horrific symptom they encountered was peeling skin. While milder cases merely involved flaking around the mouth, some accounts reported cases of full-body skin loss.

Even the thick skin on the bottoms of a patient’s feet could peel away, leaving the underlying flesh bloody and exposed. The worst cases ended in liver damage, hemorrhage, coma and death.

These explorers suffered from acute hypervitaminosis A, a condition resulting from the overconsumption of vitamin A during a short period of time.

The polar bear’s liver, much like those of arctic seals and huskies, contains extremely high levels of retinol (the form of vitamin A found in members of the animal kingdom).

3 Animals That Mate For Life

Did you know there are members of the animal kingdom (other than humans) that mate for life?

In some cases of monogamous mates – for example, beavers – both parents care for their offspring.

When one partner in a monogamous pair dies, most surviving partners go on to find a new mate before the next breeding season.




Beavers

Adult beavers can weigh 40 pounds or more, and they mate for life during their third year. Their babies are called kits, and typically 1 to 4 are born in the spring.

Both parents care for their kits, who stay with them for about two years. The yearlings typically help care for the next litter. A beaver colony can consist of six or more individuals, including parents, yearlings, and kits.

Gibbons

Gibbons are the nearest relatives to humans that mate for life. They live in small, stable family groups with a monogamous mated pair and offspring under the age of 7.

Gibbon families are territorial and defend their territory with morning songs sung by the breeding pair.

Gibbons reach sexual maturity between 6 and 8 years of age. Females give birth to one baby at a time, and mating pairs produce an average of 5 to 6 offspring over their reproductive lifetimes.

Wolves

Wolves live in packs that are typically family groups including a male and female breeding pair and their offspring of varying ages. Only the breeding pair mates, and has one litter a year.

Wolves reach sexual maturity between 2 and 3 years of age, and once the youngsters are ready to mate, most leave their birth pack to start their own pack or join an existing pack.

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What Dog And Cat Years Really Mean?

How much is that in dog years?” We are used to assuming that for every calendar year, a dog will age the way a human will in seven years.

That makes some sort of sense according to a dog’s expected life span, but it doesn’t tell the whole story.




For example, the dog in this picture has one candle on her birthday cake, but she’s old enough to have puppies. Veterinary professor Jesse Grady explains the life stages of dogs and cats.

Dogs and cats age differently not just from people but also from each other, based partly on breed characteristics and size.

Bigger animals tend to have shorter life spans than smaller ones do. While cats vary little in size, the size and life expectancy of dogs can vary greatly – think a Chihuahua versus a Great Dane.

Human life expectancy has changed over the years. And vets are now able to provide far superior medical care to pets than we could even a decade ago.

So now we use a better methodology to define just how old rule of thumb that counted every calendar year as seven “animal years.”

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