Why Bird Penises Are So Weird

This video was sponsored by 23adnMe...And
hi, Im Emily from MinuteEarth. The Argentine lake ducks spiraling penis
extends more than 16 inches. The seagull doesnt have a penis at all. For two animals with so much else in common,
this is a pretty big spectrum  in fact, birds exhibit the biggest range in relative
penis size of any class of vertebrates.

And there are a couple key reasons why. For one, male birds are uniquely set up to
pass helpful sexual traits directly to their sons  traits like showy, mate-attracting
tail feathers or genitalia of certain dimensions. Animals generally hand these kinds of traits
down through their sex chromosomes  but the sex chromosomes male mammals pass on to
their sons is pretty tiny and has relatively few genes. Male birds, on the other hand, have way bigger
sex chromosomes with lots of genes, and therefore have higher chances of passing a mutation
like one for extra-sexy tail feathers  directly to their sons, who in turn can
attract more mates and potentially pass a mutation for extra-extra sexy tail feathers
to their sons, and so on down the line.

In short, male birds comparatively huge
sex chromosomes are the reason much more exaggerated male traits have evolved in birds than in
mammals. Like the lake ducks reeeeally long penis. Male ducks often mate with unwilling females
by force, and it happens that the males with the longest and twistiest genitals are the
most successful, which means the longest-and-twistiest-genital genes keep getting passed down from father
to son. On the other hand, in bird species where less
well-endowed males do better - maybe because females prefer them, or because big genitals
make flight tough - males can end up with small nubs, or even no penises at all.

One other reason the bird penis spectrum is
so big is that its really easy to make a bird penis shrink. A single mutation on the birds large sex
chromosome triggers production of a protein that basically erases the developing embyro's
penis. All it then takes to make the entire species
penis-less is for this mutation to get passed down the line from male to male. But given how the chromosomal arrangement
of birds allows more male traits to change more easily, even penis-less-ness isnt
permanent: the chachalaca, a wild cousin of the chicken, went from having a penis, to
not having one, to growing one again.

Speaking of chromosomes, this video was sponsored
by 23andMe, which has a special interest in the chromosomes of our own species. 23AndMe not only lets you learn about your
own DNA story - including ancestry, personal traits and health insights - it can also help
you learn which one of your parents you have to thank for some of your genetic traits. To get testing kits for you and your family
- and to support our channel - go to 23andMe.Com/MinuteEarth..

Where Do Birds Go In Winter

[MUSIC] In 1971, astronaut Alan Shepard hit the first
birdie on the moon. Not literally, of course. Theres no actual birds up there. But thats not what Charles Morton thought.
In 1703 he published a pamphlet claiming that the reason some birds disappeared during winter
was because they were vacationing on the moon.

Really puts the loon in lunar [MUSIC] Throughout history, people were at a loss
as to why some birds appeared out of nowhere in the spring only to disappear again during
winter, and when it came to explaining why, their common sense flew south. Aristotle figured that certain birds didnt
leave at all, they just changed from one type to another. And a medieval scholar said geese
began life as barnacles, while another claimed they blossomed from trees every spring. The poet Homer accepted the fact that cranes
embarked on great journeys, but instead of seeking warmer weather it was to battle tribes
of mythical goat-riding dwarves at the ends of the Earth.

I am NOT making this up. Fittingly, the answer to this avian enigma
was delivered by a stork. Storks were, and still are, a common sight in Europe during
summer, except most dont have spears hanging out of their necks. After this unlucky bird
was shot in Germany, for a second time mind you, the origin of the spear was traced to
sub-Saharan Africa, proving once and for all that birds spent their winters in warmer climates.
And not the moon.

Birds dont use calendars, as far as we
know, so how do they know when to take off? By tallying observations about their environment
like changes in daylight, average temperatures, and the amount of food that there is to eat,
a biological switch is triggered that tells the bird its time to pack its feathery
bags. These days, scientists use technology ranging
from leg bands to GPS to map their incredible journeys. The arctic tern takes the longest trip of
any bird, covering as much as 50,000 miles in a single year between its Arctic and Antarctic
nesting grounds. Bar-headed geese have to cross over the Himalayas
on their annual journey, the highest migration of any bird.

To survive at those extreme altitudes,
theyve evolved specialized hemoglobin, and like other birds, they have a special
one-way respiratory system that keeps fresh air running through their lungs all the time. The great snipe is a migration speedster,
covering more than 4,000 miles at speeds up to 60 mph, while the bar-tailed godwit completes
its 7,000 mile, eight-day journey across the Pacific without stopping once, powering its
trek by packing on more than half its body mass in fat. One of the worlds most amazing bird migrations
is undertaken by one of the smallest: the ruby-throated hummingbird. Before these petite
pilots embark across the Gulf of Mexico, they too add more than half their penny-sized body
weight in fat too, and during their 600 mile trip, they burn off a quarter of their body
mass in just 20 hours! Its hard to keep weight on when you have to flap your wings
50 times a second.

Flying V! The flying V might be hockeys greatest
formation, but its also a trick to fly more efficiently. When a bird flaps its wings,
it creates a rotating vortex off the wingtip. If the bird behind is in the right place,
it can get a free boost from that updraft. Whats crazy is that birds can somehow sense
where that vortex is, and they actively flap their wings to stay in the sweet spot.

Birds are able to navigate the globe with
amazing accuracy, some returning to the same nesting spot year after year. Pigeons taken
far from home, sealed in isolation chambers cut off from light, outside air and magnetic
fields, were still able to find their way back. Its easy to see how birds might draw
a map, but what about a compass? Some birds have been found to use the sun, and others
the stars. But for many birds, they are the compass.

Tiny iron-rich crystals were discovered in
the eyes and beaks of many birds, and scientists now suspect that these allow birds to sense,
or maybe even see Earths magnetic field. We may have had some bird-brained ideas about
where our where birds disappear to, but thanks to science we know the truth is as good as
any myth. Maybe better. Stay curious..

What Happens to Birds During Hurricanes

[  Intro  ] The 2017 hurricane season sure packed a wallop. Three major storms -- Harvey, Irma, and Maria
-- decimated the Caribbean and the southern US. While the focus has rightfully been on the
impacts to those living in the storms path, you might wonder how other creatures fared. Some species seem to be able to sense the
impending danger and flee.

Landlubbers like us that dont get out of
the way just have to hunker down as best they can. But birds and other airborne animals sometimes
do what sounds like the worst idea ever: they ride things out in the eye of the storm. Meteorologists have witnessed this thanks
to something called dual-polarization or dual-pol radar, which uses pulses of electromagnetic
waves to detect the size and shape of objects in two dimensions. Based on the pattern of the waves, they can
see the proportions of whatevers in the storm  including birds and insects, which
stand out because theyre much less spherical than, say, a raindrop.

And when meteorologists map out what theyve
detected with radar, they often find a bunch of animals inside the eyes of big storms. Heading into a hurricane for safety sounds
pretty bold  and ill-advised. But within the eye, the weather is calm. Its a spot of extremely low pressure, which
helps drive the overall storm, but isnt very windy itself.

It doesnt even have clouds, since the air
in the eye is about 5 degrees warmer than the rest of the storm, and it can hold more
water before condensing. So, all things considered, its relatively
safe for birds and bugs. Not that its an intentional strategy on
their partthey probably dont plan this out. Either the eye forms around them, or they
just happen to find the eye and then end up kinda stuck there.

This especially happens with seabirds. The real danger is running into the eyewall,
the vertical wall of clouds that surrounds the eye, which is the most intense part of
the storm. It has the heaviest rainfall and strongest
winds. Sticking to the eye can work, but it can be
tough to make it through if a hurricane is especially long-lived.

Trapped birds dont have much choice but
to keep flappingthey cant really stop to sleep or eatso this kind of travel can
wear them out. Sometimes they die. And since, you know, a hurricane swept through
their habitat, there may not be much left to come home to. Or, if theyre migratory birds, they can
be blown hundreds of kilometers off course.

In 2005, Hurricane Wilma deposited a flock
of North American chimney swifts in Western Europe. More than 700 of the birds died, and ornithologists
found that the following year, the total population had been cut in half. It can be hard to collect good data on what
happens to birds during and after a storm, as each hurricane is different. But birdwatchers can help with that.

Safety first, obviously, but if you ever see
hurricane birdsspecies well outside of their usual homes during or after a stormyou
can report your observations so scientists can learn more about how animals deal with
tropical cyclones. Its one of the more unusual types of citizen
science. Thanks for asking, and thanks as always to
all our patrons on Patreon. Your support helps us weather any storm.

If you want to help us make more episodes
like this, you can go to patreon.Com/scishow. [  Outro  ].