Sexier Posterior Evolves Almost Overnight

Male barn swallows attract females with long tail feathers, and European researchers have observed that over the last 20 years those feathers have become much longer.

"We've demonstrated quite a dramatic change in a short period of time," said Dr. Anders Pape Moller, an evolutionary biologist at Pierre and Marie Curie University in Paris, who conducted the research with Dr. Tibor Szep of the College of Nyiregyhaza in Hungary. The findings are to be published in The Journal of Evolutionary Biology.

Experiments suggest that the males' tails act as advertising for good genes because males must be in good health to spend the energy growing them. The females, the researchers say, are particularly attracted by the tail's two outer feathers.

Dr. Moller, who has been documenting this preference for more than two decades, found that the outer feathers had lengthened by almost half an inch (11.4 millimeters), an increase of 10 percent, one of the biggest evolutionary shifts ever documented in a living population of wild animals. By contrast, the central tail feathers, which don't produce a reaction in females, haven't changed.

Over the last 30 years, researchers have made more than 1,500 measurements of natural selection in wild populations of animals and plants. Droughts on the Galápagos Islands, for example, have favored larger beaks in finches, because the surviving seeds are harder to crack. But the shift measured by Dr. Moller and Dr. Szep is greater.

Dr. Moller and Dr. Szep suspect that the agent for this is the long-term spread of the Sahara. The barn swallows they are examining migrate from Denmark to South Africa for the winter, then return by way of Algeria in the spring. The reduction of vegetation there around the desert may mean fewer insects for the hungry swallows.

"If they get across the Sahara and there's nothing to eat, it's tough," Dr. Moller said. Weaker male swallows starve; stronger ones reach Denmark. There they pass on their genes to the next generation - including genes for longer tails.

"I am prepared to believe that the birds are probably evolving, but not that climate change is the cause, simply because there can be so much else going on," said Dr. David Reznick, an evolutionary biologist at the University of California at Riverside.

Oh, my, god. Becky, look at her butt.
It is so big. *scoff* She looks like,
one of those rap guys' girlfriends.
But, y'know, who understands those rap guys? *scoff*
They only talk to her, because,
she looks like a total prostitute, 'kay?
I mean, her butt, is just so big. *scoff*
I can't believe it's just so round, it's like,
out there, I mean - gross. Look!
She's just so ... black!

[Sir Mix-a-Lot]
I like big butts and I can not lie
You other brothers can't deny
That when a girl walks in with an itty bitty waste
And a round thing in your face
You get sprung, wanna pull up tough
'Cause you notice that butt was stuffed
Deep in the jeans she's wearing
I'm hooked and I can't stop staring
Oh baby, I wanna get wit'cha
And take your picture
My homeboys tried to warn me
But with that butt you got makes
Ooh, Rump-o'-smooth-skin
You say you wanna get in my Benz?
Well, use me, use me
'Cause you ain't that average groupy
I've seen them dancin'
The hell with romancin'
She's wet, wet,
Got it goin' like a turbo 'Vette
I'm tired of magazines
Sayin' flat butts are the thing
Take the average black man and ask him that
She gotta pack much back
So, fellas! (Yeah!) Fellas! (Yeah!)
Has your girlfriend got the butt? (Hell yeah!)
Tell 'em to shake it! (Shake it!) Shake it! (Shake it!)
Shake that healthy butt!
Baby got back!

(LA face with Oakland booty)
Baby got back!

[Sir Mix-a-Lot]
I like 'em round, and big
And when I'm throwin' a gig
I just can't help myself, I'm actin' like an animal
Now here's my scandal
I wanna get you home
And ugh, double-up, ugh, ugh
I ain't talkin' bout Playboy
'Cause silicone parts are made for toys
I want 'em real thick and juicy
So find that juicy double
Mix-a-Lot's in trouble
Beggin' for a piece of that bubble
So I'm lookin' at rock videos
Watchin' these bimbos walkin' like hoes
You can have them bimbos
I'll keep my women like Flo Jo
A word to the thick soul sistas, I wanna get with ya
I won't cuss or hit ya
But I gotta be straight when I say I wanna *fuck*
Til the break of dawn
Baby got it goin' on
A lot of simps won't like this song
'Cause them punks like to hit it and quit it
And I'd rather stay and play
'Cause I'm long, and I'm strong
And I'm down to get the friction on
So, ladies! {Yeah!} Ladies! {Yeah}
If you wanna role in my Mercedes {Yeah!}
Then turn around! Stick it out!
Even white boys got to shout
Baby got back!

Baby got back!
Yeah, baby ... when it comes to females, Cosmo ain't got nothin'
to do with my selection. 36-24-36? Ha ha, only if she's 5'3".

[Sir Mix-a-Lot]
So your girlfriend rolls a Honda, playin' workout tapes by Fonda
But Fonda ain't got a motor in the back of her Honda
My anaconda don't want none
Unless you've got buns, hon
You can do side bends or sit-ups,
But please don't lose that butt
Some brothers wanna play that "hard" role
And tell you that the butt ain't go
So they toss it and leave it
And I pull up quick to retrieve it
So Cosmo says you're fat
Well I ain't down with that!
'Cause your waste is small and your curves are kickin'
And I'm thinkin' bout stickin'
To the beanpole dames in the magazines:
You ain't it, Miss Thing!
Give me a sista, I can't resist her
Red beans and rice didn't miss her
Some knucklehead tried to dis
'Cause his girls are on my list
He had game but he chose to hit 'em
And I pull up quick to get wit 'em
So ladies, if the butt is round,
And you want a triple X throw down,
Dial 1-900-MIXALOT
And kick them nasty thoughts
Baby got back!

(Little in the middle but she got much back) [4x]

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