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Eggs come in a variety of colours -- white, brown, blue, green, and speckled.
鸡蛋有很多种颜色--白色、棕色、蓝色、绿色，还有有斑点的鸡蛋。
The difference in shell pigmentation is superficial,
蛋壳颜色的差异只是一种表面现象，
but the reasons are genetic and evolutionary, dating all the way back to dinosaurs.
其原因则跟遗传和进化有关，甚至可以一直追溯到恐龙时代。
Let’s start with the familiar white and brown chicken eggs.
我们先来说说大家熟悉的白鸡蛋和棕色鸡蛋。
You might have a preference, but one doesn’t have more protein or a better taste than the other,
你可能更喜欢两种鸡蛋中的某一种，但说到蛋白质含量和口感，它们谁也不比谁更好，
though brown eggs tend to have slightly more Omega-3 fatty acids.
尽管棕色鸡蛋的欧米茄-3脂肪酸含量通常会稍微高那么一点点。
Brown eggs also come from larger chickens that cost more to maintain,
另外，产棕色鸡蛋的鸡的体型也比产白色鸡蛋的鸡的体型更大一些，所以饲养成本也更高一些，leghorn chickens
which is why those eggs are a little more expensive.
这就是为什么这种鸡蛋会贵那么一点点的原因。
It’s not because they’re way better.
可见，它们贵并不是因为它们比白鸡蛋好。
Brown eggs get their color from a biochemical pigment called protoporphyrin formed by blood cells breaking down.
棕色鸡蛋的颜色来源于一种由血细胞分解形成的，名为“原卟啉”的生化色素。
And of course biochemical pigments are due to genetics.
当然了，生化色素是由遗传决定的。
White-feathered chickens with white earlobes called Leghorn chickens lay white eggs
产白色蛋的是白色耳垂的白羽鸡，又名“来航鸡”，
while one type of red or brown chickens with red earlobes called Orpingtons lay brown eggs.
产棕色蛋的是一种红色或棕色耳垂的“奥平顿鸡”。
But, it gets weirder.
接下来要介绍的鸡蛋（颜色）一个比一个奇怪。
The Ameraucana breed lays blue eggs, giving it the nickname of the Easter egg chicken.
Ameraucana鸡产的是蓝色的鸡蛋，这种鸡也因此得了个绰号：“复活节蛋鸡”。
Olive Eggers, a cross between a hen and rooster that are from a brown egg and a blue egg laying breed, lays olive green eggs.
产棕色鸡蛋的（奥平顿）母鸡和Ameraucana公鸡杂交诞下的橄榄蛋鸡产的则是橄榄绿色的鸡蛋。
In each case, the pigment is deposited on the egg as it moves through the hen’s oviduct, fairly late in the shell-forming process --
以上每种鸡蛋的色素都是它们在母鸡的输卵管中移动时转移到鸡蛋上的，这个过程具体发生在蛋壳形成晚期——
the last 3 to 6 hours of a 20 to 26 hour process -- so the color doesn’t actually pass all the way through the shell.
鸡蛋成形需要20~26个小时，色素则是在最后3~6个小时转移到鸡蛋上的——所以，蛋壳的颜色并不会穿透整个蛋壳。
If you look at the inside of the shell of a brown egg after you crack it, the inside is white, not brown like the outside.
如果你打开一个棕色的鸡蛋看蛋壳的内侧，你会发现内侧是白色，并不是蛋壳外面那种棕色。
But aside from genetics, there are other factors that can influence an individual egg’s pigment.
不过，除了遗传，还有其他影响单个鸡蛋颜色的因素。
A bigger egg would need more pigment to cover it,
个头大的鸡蛋需要的色素就多，
so if the hen only releases a set amount, that egg can be lighter.
所以，如果一只母鸡释放的色素的量恒定，那蛋壳的颜色就会相对浅一些。
An older hen will generally lay lighter eggs.
年龄较大的母鸡产的蛋颜色往往都比较浅。
The egg can rotate as it moves through the hen, too, meaning pigment can be unevenly distributed.
鸡蛋在母鸡体内移动时也会发生旋转，这就意味着蛋壳颜色的分布可能会不均匀。
Stress on the hen can lead to less pigment and a lighter egg as well.
压力也会导致母鸡释放的色素减少，继而产下颜色较浅的鸡蛋。
As for the more interesting colors we see, such as the blue eggs,
而我们看到的颜色比较有意思的鸡蛋，比如蓝色的鸡蛋，
the color comes from a pigment called oocyanin, a by-product of bile production.
它们的颜色则是来自一种名为“卵蓝蛋白”的色素，这种色素又是胆汁分泌的一种副产品。
But there's an evolutionary advantage to blue eggs,
不过，蓝色鸡蛋在进化方面有一定的优势，
since birds like robins and emus lay their eggs in an open nest.
因为知更鸟，鸸鹋之类的鸟都是在在开放的巢中产蛋。
The blue pigment filters out UV light, protecting the egg from sunlight and stopping it from overheating.
蓝色色素可以过滤紫外线，保护鸡蛋不受阳光的伤害，还能防止其被烤熟。
The darker blue eggs are generally found in environments where there’s less direct sunlight;
深蓝色的蛋通常会出现在阳光直射较少的地方；
the darker pigment absorbs more sunlight to warm the egg.
这样较深的色素就能吸收更多的阳光给蛋保温。
Speckled eggs, meanwhile, have inherent protection from predators, offering a bit of camouflage while they sit in a nest.
与此同时，有斑点的蛋等于天然拥有了一层保护伞，因为在巢中的时候，那些斑点能够发挥一定的伪装作用。
This explains why other egg-laying animals lay unpigmented eggs, like turtles.
其他产卵动物，比如海龟，之所以要产无颜色的蛋也是这个原因。
Turtles bury their eggs in a protected nest so don’t need the UV protection or camouflage.
因为海龟会将它们的蛋埋起来，所以不需要紫外线保护或伪装。
This all has led scientist to conclude that egg colours came about
因为上述种种现象，科学家们得出了一个结论，蛋的颜色是在鸟类
around the time that species starting laying eggs in uncovered nests rather than bury them,
开始在非封闭巢穴中产蛋，而不再像恐龙一样产完蛋之后便将它们埋起来——
something dinosaurs species like these were known to do.
在这方面，这些恐龙都是出了名的——之后开始出现的。
So which ever eggs you choose to buy, you’re making an egg-cellent choice.
综上所述，无论你买的是那种鸡蛋，你做的都是“鸡佳的”选择。
For more science content be sure to subscribe to seeker!
想了解更多科学内容，就赶紧订阅我们的栏目吧！
Speaking of dinosaur eggs, Trace can tell you what we can learn from them in this video right here.
说到恐龙蛋，Trace在这个视频里分享了我们能从它们身上学到什么。
Thanks for sticking around till the end!
感谢大家收看到最后！
And speaking of sticking and egg colours, fish eggs are coloured depending on the female, not the species!
而说到蛋的颜色，鱼蛋的颜色其实取决于雌鱼，而非鱼的种类！
