Archive for the ‘eagle’ Category

For hundreds of years in the skies over Asia, people have used eagles to hunt down prey with deadly results.

That tradition has been in decline for decades, but now the bird’s keen eyesight, powerful talons and lethal hunting instincts are being used to take out a new kind of 21st-century vermin: drones.

The animal-vs.-machine moment is brought to you by Guard From Above, which describes itself as “the world’s first company specialized in training birds of prey to intercept hostile drones.”

The Hague-based company’s latest customers are Dutch police, who have been looking for ways to disable illegally operating drones. A police spokesman told Dutch News.nl that the effort remains in a testing phase, but he called the use of birds to combat drones a “very real possibility.”

“It’s a low-tech solution to a high-tech problem,” national police spokesman Dennis Janus told Reuters.

He added: “People sometimes think it’s a hoax, but it’s proving very effective so far.”

The rise of drone technology has been matched in speed by the rise of anti-drone technology, with companies creating radio jammers and “net-wielding interceptor” drones to disable quadcopters, according to the Verge.

“For years, the government has been looking for ways to counter the undesirable use of drones,” Guard From Above’s founder and chief executive, Sjoerd Hoogendoorn, said in a statement. “Sometimes a low-tech solution for a high-tech problem is more obvious than it seems. This is the case with our specially trained birds of prey. By using these birds’ animal instincts, we can offer an effective solution to a new threat.”

A video released on Sunday by Dutch police shows an eagle swooping in at high speed to pluck a DJI Phantom out of the air using its talons. The drone is immediately disabled as the bird carries it off.

“The bird sees the drone as prey and takes it to a safe place, a place where there are no other birds or people,” project spokesman Marc Wiebes told Dutch News.nl. “That is what we are making use of in this project.”

Said Hoogendoorn, according to Reuters: “These birds are used to meeting resistance from animals they hunt in the wild, and they don’t seem to have much trouble with the drones.”

Janus, the police spokesman, told the Associated Press that the birds get a reward if they snag a drone.

Eagles’ talons, as the New York Daily News points out, are known for their powerful grips; it’s unknown whether they could be damaged by a drone’s carbon-fiber propellers.

HawkQuest, a Colorado nonprofit that educates the public about birds of prey, says eagles have enough power to “crush large mammal bones” in animals such as sloths.

“Scientists have tried to measure the gripping strength of eagles,” HawQuest notes. “A Bald Eagle’s grip is believed to be about 10 times stronger than the grip of an adult human hand and can exert upwards of 400 psi or pounds per square inch.”

According to a study cited by Wired in 2009, raptor talons are not merely powerful, but also finely tuned hunting instruments:

“…accipitrids, which include hawks and eagles, have two giant talons on their first and second toes. These give them a secure grip on struggling game that they like to eat alive, ‘so long as it does not protest too vigorously. In this prolonged and bloody scenario, prey eventually succumb to massive blood loss or organ failure, incurred during dismemberment.’”

A handler in the video, the Daily News notes, claims the birds are adequately protected by scales on their feet and legs, but researchers hope to equip the animals with another layer of defense.

The potential impact on the animals’ welfare is the subject of testing by an external scientific research institute.

“The real problem we have is that they destroy a lot of drones,” Hoogendoorn said, according to Reuters. “It’s a major cost of testing.”

The decision about whether to use the eagles is still several months away.

https://www.washingtonpost.com/news/worldviews/wp/2016/02/01/trained-eagle-destroys-drone-in-dutch-police-video/

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