Bird Belly Buttons is a fanfic dedicated to the fandom, the title pretty much says it all.
While the penguins were surveying before opening time Skipper caught sight of Mort probing his fingers into his belly, "uh Mort how long have you been messing with your bellybutton?" Maurice asked, slightly grossed out, "cause it's fun, and I keep finding these hairballs in it" Mort answers holding up some lint, Maurice recoils from it, "wait our bellybuttons can cough up hairballs?" Julien asks suddenly interested, "I wouldn't say cough up, it just grows in them" Maurice explains looking at his own mid section disgusted, and was even more disgusted that Julien was doing it too, Maurice walks away cringing.
"That was disturbing" Skipper agreed as he and the other penguins witnessed it, Private looked just as grossed out, Kowalski actually looked curious and Rico was smiling at it, "ah the mammalian navels make the perfect home for dusty materials" Kowalski explains, "wait you mean if we had bellybuttons, there would be dust in them?" Private wonders, "well...yes" Kowalski answers, Private grimaces and looks at his own belly, Rico was skimming his belly with his hands for anything that felt like a navel, "will you two cut it out," Skipper orders, Private and Rico did, "us birds are bellybuttonless, if that's a word, but anyway you don't have to worry about having hairballs coming out of your stomach", Private relaxes, but Rico looked a bit disappointed, as if he was hoping to have a bellybutton.
Then Alice came by with some school kids over to the lemurs, "hey are those two lemurs playing with their bellybuttons?" one boy asks, and everyone else noticed it too, some were laughing, others were grossed out, Alice was unsure of how to make it, but the same kid asked if the penguins had any bellybuttons, which Alice was unsure of how to answer but decides to move on to the next exhibit, the penguins had mixed expressions, Private was cringing, Rico laughed a little, Skipper and Kowalski just looked on with weird faces.
Alice was getting nagged by the question all day though, until she couldn't take it anymore and decides to ask the other zoo employees, but all of them were just as answerless, so Alice decided to bring the penguins to the vet.
Meanwhile the penguins were enjoying their time after opening hours when cages were dropped on them again, "aw not again" Skipper complained, eventually they were placed on a table, "well dock here they are" Alice states, the doctor had what looked like a razor in his hand, "well I have found a book about birds, here look" the doctor says opening a book about birds, to the penguin's surprise they heard that birds do have bellybuttons, "it says here: In the egg there is a cord that attaches the developing embryo to the yolk sac. When the bird hatches, there is a residual scar where the cord used to be. While the bird is a nestling, you can still see what would be the avian equivalent of a belly button." the doctor read then added, "but why don't we find out for ourselves".
He then scoops up Private and places him on a separate table, none of the penguins resisted but they still think what the humans think is wrong, that is until Private's belly was shaved of it's feathers from the crotch to the chest, the doctor and Private look at the now exposed skin and to both surprises, there was a dot on Private's belly, "well, well, well, looks like birds do have bellybuttons after all" the doctor guessed, "finally" Alice cheers, Private couldn't believe it though and neither could the other penguins, they all thought for sure birds lacked bellybuttons, the doctor wasn't done yet though as he returned Private back and took Kowalski, Private hid his mid-section with his flippers as Skipper was too shocked to move and Rico was resisting laughter that was building up.
Eventually all four penguins had their tummies shaved which revealed that they each had bellybuttons, they couldn't believe that they were proven wrong and embarrassed that now the whole world could see it, "oh the inhumanity" Skipper complains looking at his newly discovered navel, Private wrapped a towel around himself to hide his own, Kowalski was studying his navel, taking some lint samples too, and Rico was playing with his, he was possibly the only one who wasn't ashamed or embarrassed to have his belly's skin visible, and would often show off with it too.
Just then Marlene came over, "hey guys how-holy moly!" she exclaims when she caught sight of Rico's featherless belly, Skipper and Kowalski were obscuring theirs with their arms but it was no use, she could see their bare bellies too, she had a good guess though, "wait did they actually take you to the vet to find out you have bellybuttons?" she asks, "you know about that?" Private asks back, "well the whole zoo heard that Mort and Julien were playing with theirs, and we heard the same school kid asking if you had any, and it looks like I was right" she finishes, staring at Rico who was showing off his belly goofily, then added, "and I thought birds didn't have bellybuttons".
"So did we" Kowalski remarked, then to the penguin's further embarrassment the lemurs arrive, "aha so it is true, told you Maurice" Julien cheers, "Ringtail do you mind?" Skipper growled, "yes I am to be minding" Julien retorted and began to poke Rico's navel who blushes laughing in the process, then did Kowalski and Private and was down to Skipper, "oh what's the use, the whole world is bound to know anyway" Skipper complains again and removes his arms, letting Julien poke his bellybutton despite not enjoying it.
The next day when the penguins were doing training all other zoo animals were aware about the 'penguin navels', the chimps, and gorillas were showing off their own bellybuttons to Rico in a 'best bellybutton' contest, Roger, Shelly, Leonard, Burt and Barry were creeped out, at the same time agreed that they thought it was all false too, Joey, Roy, Pinky, Bitsy and Ted were grossed out and kept trying to avoid looking, the penguin's embarrassment grew more when Alice began to take advantage of it and let people see, again Rico was the only one not ashamed or embarrassed and continues to show off, earning laughter and disgust, Private was the complete opposite as his face was as red as an apple, Kowalski and Skipper decide to just go with the flow.
By the end of the day the penguins could relax, Kowalski became obsessed with studying his navel and Rico still doesn't show signs of getting tired of his, Skipper eventually succumbed to the fun of navels as he was playing with his own, "aw come on Private it isn't all bad" Skipper offered to Private, who was the only one not interested in navels, "as if" Private objected, Skipper gave up but Rico decides to try to change his mind, "if you're going to say the same thing the answer is still no" Private accused, Rico shook his head innocently, "than what is it?" Private demanded facing Rico fully, that was a mistake though as Rico lunged at Private's bellybutton with his beak and began spitting in it, Skipper giggled when he notices, Kowalski too, Private struggled at first but succumbed to the tickle, "okay okay you win Rico" Private wheezed through, Rico lets him recover and said "told ya it is fun".
"Well better enjoy it while it lasts cause our feathers will grow back and hide it all" Skipper states, Private couldn't deny it anymore as he was probing his bellybutton with his flipper, he had to admit despite the grossness bellybuttons can give, playing with them was fun.