Archive for the ‘chicken’ Category

Duck_chicken_penisRooster

Researchers have now unraveled the genetics behind why most male birds don’t have penises, just published in Current Biology.
[Ana Herrera et al, Developmental Basis of Phallus Reduction During Bird Evolution]

There are almost 10,000 species of birds and only around 3 percent of them have a penis. These include ducks, geese and swans, and large flightless birds like ostriches and emus. In fact, some ducks have helical penises that are longer than their entire bodies. But eagles, flamingos, penguins and albatrosses have completely lost their penises. So have wrens, gulls, cranes, owls, pigeons, hummingbirds and woodpeckers. Chickens still have penises, but barely—they’re tiny nubs that are no good for penetrating anything.

In all of these species, males still fertilise a female’s eggs by sending sperm into her body, but without any penetration. Instead, males and females just mush their genital openings together and he transfers sperm into her in a maneuver called the cloacal kiss.

To get to the root of this puzzle, researchers compared the embryos of chickens and ducks. Both types of birds start to develop a penis. But in chickens, the genital tubercle shrinks before the little guys hatch. And it’s because of a gene called Bmp4.

“There are lots of examples of animal groups that evolved penises, but I can think of only a bare handful that subsequently lost them,” says Diane Kelly from the University of Massachusetts in Amherst. “Ornithologists have tied themselves in knots trying to explain why an organ that gives males an obvious selective advantage in so many different animal species disappeared in most birds. But it’s hard to address a question on why something happens when you don’t know much about how it happens.”

That’s where Martin Cohn came in. He wanted to know the how. His team at the University of Florida studies how limbs and genitals develop across the animal kingdom, from the loss of legs in pythons to genital deformities in humans. “In a lab that thinks about genital development, one takes notice when a species that reproduces by internal fertilization lacks a penis,” says graduate student Ana Herrera.

By comparing the embryos of a Pekin duck and a domestic chicken, Herrera and other team members showed that their genitals start developing in the same way. A couple of small swellings fuse together into a stub called the genital tubercle, which gradually gets bigger over the first week or so. (The same process produces a mammal’s penis.)

In ducks, the genital tubercle keeps on growing into a long coiled penis, but in the chicken, it stops around day 9, while it’s still small. Why? Cohn expected to find that chickens are missing some critical molecule. Instead, his team found that all the right penis-growing genes are switched on in the chicken’s tubercle, and its cells are certainly capable of growing.

It never develops a full-blown penis because, at a certain point, its cells start committing mass suicide. This type of ‘programmed cell death’ occurs throughout the living world and helps to carve away unwanted body parts—for example, our hands have fingers because the cells between them die when we’re embryos. For the chicken, it means no penis. “It was surprising to learn that outgrowth fails not due to absence of a critical growth factor, but due to presence of a cell death factor,” says Cohn.

His team confirmed this pattern in other species, including an alligator (crocodilians are the closest living relatives of birds). In the greylag goose, emu and alligator, the tubercle continues growing into a penis, with very little cell death. In the quail, a member of the same order as chickens, the tubercle’s cells also experience a wave of death before the organ can get big.

This wave is driven by a protein called Bmp4, which is produced along the entire length of the chicken’s tubercle, but over much less of the duck’s. When Cohn’s team soaked up this protein, the tubercle’s cells stopped dying and carried on growing. So, it’s entirely possible for a chicken to grow a penis; it’s just that Bmp4 stops this from happening. Conversely, adding extra Bmp protein to a duck tubercle could stop it from growing into its full spiralling glory, forever fixing it as a chicken-esque stub.

Bmp proteins help to control the shape and size of many body parts. They’re behind the loss of wings in soldier ants and teeth of birds. Meanwhile, bats blocked these proteins to expand the membranes between their fingers and evolve wings.

They also affect the genitals of many animals. In ducks and geese, they create the urethra, a groove in the penis that sperm travels down (“If you think about it, that’s like having your urethra melt your penis,” says Kelly.) In mice, getting rid of the proteins that keep Bmp in check leads to tiny penises. Conversely, getting rid of the Bmp proteins leads to a grossly enlarged (and almost tumour-like) penis.

Penises have been lost several times in the evolution of birds. Cohn’s team have only compared two groups—the penis-less galliforms (chickens, quails and pheasants) and the penis-equipped anseriforms (swans, ducks and geese). What about the oldest group of birds—the ratites, like ostriches or emus? All of them have penises except for the kiwis, which lost theirs. And what about the largest bird group, the neoaves, which includes the vast majority of bird species? All of them are penis-less.

Maybe, all of these groups lost their penis in different ways. To find out, Herrera is now looking at how genitals develop in the neoaves. Other teams will no doubt follow suit. “The study will now allow us to more deeply explore other instances of penis loss and reduction in birds, to see whether there is more than one way to lose a penis,” says Patricia Brennan from the University of Massachussetts in Amherst.

And in at least one case, what was lost might have been regained. The cracids—an group of obscure South American galliforms—have penises unlike their chicken relatives. It might have been easy for them to re-evolve these body parts, since the galliforms still have all the genetic machinery for making a penis.

We now know how chickens lost their penises, but we don’t know why a male animal that needs to put sperm inside a female would lose the organ that makes this possible. Cohn’s study hints at one possibility—it could just be a side effect of other bodily changes. Bmp4 and other related proteins are involved in the evolution of many bird body parts, including the transition from scales to feathers, the loss of teeth, and variations in beak size. Perhaps one of these transformations changed the way Bmp4 is used in the genitals and led to shrinking penises.

There are many other possible explanations. Maybe a penis-less bird finds it easier to fly, runs a smaller risk of passing on sexually-transmitted infections, or is better at avoiding predators because he mates more quickly. Females might even be responsible. Male ducks often force themselves upon their females but birds without an obvious phallus can’t do that. They need the female’s cooperation in order to mate. So perhaps females started preferring males with smaller penises, so that they could exert more choice over whom fathered their chicks. Combinations of these explanations may be right, and different answers may apply to different groups.

Thanks to Dr. Lutter for bringing this to the It’s Interesting community.

http://www.oddly-even.com/2013/06/06/how-chickens-lost-their-penises-and-ducks-kept-theirs_/

http://news.yahoo.com/why-did-chicken-lose-penis-165408163.html

No, it’s not the latest eye-popping item from the always entertaining Weekly World News. Instead, it’s an actual headline from the October 22, 1945, issue of LIFE magazine, above an article about … well, a headless chicken: “Beheaded Chicken Lives Normally After Freak Decapitation by Ax.”

“Ever since Sept. 10,” LIFE informed its readers, “a rangy Wyandotte rooster named Mike has been living a normal chicken’s life though he has no head.” Mike, it seems, “lost his head in the usual rooster way. Mrs. L.A. Olson, wife of a farmer in Fruita, Colo., 200 miles west of Denver, decided to have chicken for dinner. Mrs. Olson took Mike to the chopping block and axed off his head. Thereupon Mike got up and soon began to strut around…. What Mrs. Olson’s ax had done was to clip off most of the skull but leave intact one ear, the jugular vein and the base of the brain, which controls motor function.”

The rest is poultry history. Mike lived for 18 months after losing his head, finally succumbing at a motel in the Arizona desert in 1946 during one of his many appearances as a sideshow attraction in the American southwest.

Here, LIFE.com presents Mike’s unlikely story, as well as the utterly unsettling pictures that ran (and some that never ran) in LIFE.

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Mike the headless chicken “dances” in 1945.

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Mike the headless chicken in his Colorado barnyard, with fellow chickens, 1945.

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A picture of the suitcase containing the tools for feeding Mike the headless chicken, including an eye dropper that was used to provide sustenance through the hole atop his torso where his head used to be.

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Mike the headless chicken is fed through an eye dropper, directly into his esophagus, in 1945.

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Promoter Hope Wade holds Mike the headless chicken’s formerly useful noggin, as if attempting to reintroduce the bird to its lost self, in 1945. (Some reports, however, claim that the Olsons’ cat ate Mike’s head, and that another rooster’s head stood in for Mike’s during his brief brush with fame.)

Thanks to Ray Gaudette for bringing this to the attention of the It’s Interesting community.

Read more: http://life.time.com/curiosities/photos-mike-the-headless-chicken-beyond-belief/#ixzz2OZ1jpmWC

A Wisconsin couple says a pet chicken named Cluck Cluck saved them from a fire. Dennis Murawska, 59, said Cluck Cluck woke his wife with loud clucking from its cage in the basement two floors below about 6:15am yesterday. They got out in time, and firefighters later saved the chicken. “We are used to hearing about a dog or cat or something, but we never heard of a chicken waking up a resident for a fire,” says the fire chief in Alama Center. “That’s pretty amazing.”

Cluck Cluck came from a nearby farm. When the chicken began wandering over to Murawska’s house, his neighbor said he could kill it because it wasn’t producing any eggs. But Murawska felt sorry for Cluck Cluck because she had a mutated foot and decided to keep her. He fed the bird and built a coop, and then his wife let Cluck Cluck into the basement on cold nights. “I spent way more money than I ever should’ve,” Murawska said by telephone. “I guess it paid off.”

http://www.newser.com/story/160053/pet-chicken-saves-couple-from-fire.html?utm_source=syn&utm_medium=goognews&utm_campaign=chan3_feed

 

A Delmar man faces several criminal charges after his alleged actions caused the deaths of almost 70,000 chickens.

Joshua D. Shelton, 21, was charged in connection with the incident. Police said Shelton reportedly shut off the power to three chickenhouses.

“The theory is that he may have been in there looking for a light switch,” said Lt. Tim Robinson of the Wicomico County Sheriff’s Office.

The value of these chickens, belonging to Mark Shockley of the 32000 block of E. Line Road in Delmar, is reported to be about $20,000, and damage also includes an unknown amount of cleanup costs, according to charging documents. After the incident, only about 100 chickens remained, charging documents state.

Shockley found the chickens Saturday morning and the flock, which had been deprived of food, water and cooling fans, was supposed to be delivered on Sunday.

“Shockley advised that without power, the chickens will begin to die within 15 minutes,” according to charging documents.

Shelton was found lying in the power control shed by the circuit breakers, wearing a T-shirt and boxers, the sheriff’s office reported.

He smelled of alcohol and did not know how he got into the shed or remember touching the breakers, according to charging documents.

Shelton is charged with second-and fourth-degree burglary, malicious destruction of property, trespassing on private property and animal cruelty.

Shelton was at a gathering outside the home with a few people — including Shockley’s daughter — according to charging documents. After his daughter told everyone to go home, she thought Shelton had left.

“Instead of leaving, he wandered into the shed where the power controls were and ended up turning off the power,” Robinson said.

Crimes involving the death of a mass number of chickens are not common, Robinson said.

“This is a first for me in my almost 20-year career,” Robinson said.

An incident like this is also surprising to Bill Satterfield, executive director of Delmarva Poultry Industry Inc.

“I have never heard of a drunkard going in and killing chickens,” he said. “This is a new one on me, and it’s unfortunate that it occurred.”

Satterfield said occasionally there will be reminders in a newsletter that goes out about protecting chickens from intrusion, but the problem is more likely to be people bringing in bacteria, or potentially animal rights people.

He recommended growers install locks and gates, lock the doors on chickenhouses and put up “No trespassing” or “No admittance” signs.

While Satterfield wasn’t familiar with this particular case, he said it takes chickens about an average of seven weeks to grow, and a farmer may get five or five-and-a-half flocks per year.

“If he’s losing the entire flock, that would be about one-fifth of his income for the year,” Satterfield said.

http://www.delmarvanow.com/article/20120828/WIC01/208280380/Farmer-finds-nearly-70-000-chickens-dead