(children please read under guidance)

Duck Tintin is very impressive.

first of all, as a bird, having Tintin may be impressive in itself-because most birds don't. Ninety-seven percent of birds do not have Tintin, they just use cloacal contact to reproduce, a form of mating that scientists call a cloacal kiss.

("cloacal Kiss," birds without Tintin, such as chickens)

and ducks not only have considerable length of Tintin, but also have a very rugged shape-yes, you may already know, it's like a natural wine bottle opener, it's spiral.

unlike the mammals we are familiar with, the duck's Tintin is usually hidden. The dynamic picture below shows the Tintin of a Muscovy duck, which takes only 0.35 seconds to show its fullness, which is 20 centimeters long. And this is not the longest, the South American hard-tailed duck even has a record of 42.5 centimeters in length, which is also a world record.

(1.6 meters per second). (this is high-speed photography)

Are you looking for a perfect light pink bridesmaid dresses to shine like a star? Buy now at prices that will amaze you!

at this point, this is also a yellow violent and interesting animal story. But the whole story is much more than that. In fact, the reproduction of ducks reflects an extremely rugged "war between the sexes".

many ducks mate during the breeding season, but violent mating still occurs from time to time: other males choose to mate forcibly with females. In order to gain an advantage in conflict, male ducks have evolved long and rugged Tintin so that they can better pass their sperm to the female.

at the same time, seemingly aggrieved female ducks have evolved corresponding antagonistic structures. Their reproductive tract is as long and rugged as males, and they have a blind end and a spiral structure in the opposite direction.

(rugged duel: on the right is a counterclockwise spiral Tintin of a male mallard, and on the left is a female with a clockwise spiral)

female ducks may not be able to escape forced mating, but they can still choose whose genes they transmit. In mallard ducks, forced mating can account for 35%, but only 35% of males succeed in leaving offspring, and the rugged structure of the reproductive tract plays an important role in fending off uninvited sperm. Only when the female cooperates, the male sperm can fully get close to the egg.

(a schematic diagram of stopping males. I just want to say that this is the legendary spiral of contradiction. You will probably be killed by fans of the empty realm _ (: empty) ∠) _)

actually posted a moving picture of the duck before, but I still want to explain it more clearly. I said I would like to buy this bottle opener.

reference: http://www.the-scientist.com/?articles.view/articleNo/40321/title/The-Hidden-Side-of-Sex/