The plot is set in motion when a man named Mr. Morehouse goes to a parcel office at a train station to collect two guinea pigs. He expects to pay twenty-five cents, the rate for sending domestic pets by rail, for each animal. Mike Flannery, who runs the parcel office, insists that the rate for sending domestic pets does not apply to guinea pigs. He believes that guinea pigs are a kind of pig and that Morehouse should pay sixty cents, the charge for transporting two pigs, for the animals. Morehouse refuses to pay the higher charge and complains to the railroad company. While Morehouse waits for the matter to be resolved, the guinea pigs are left in Flannery's care. The two guinea pigs soon have six children. After a few months, Flannery finds himself having to take care of thousands of the little animals.
"Pigs Is Pigs" has been adapted as a 1914 American silent film and as a 1954 short animated cartoon from Walt Disney. The 1937 Warner Bros. short animated cartoon Pigs Is Pigs is not an adaptation of the story.
Readers should be aware that there are a number of ethnic slurs in "Pigs Is Pigs". The character of Mike Flannery is a stereotypical foolish Irishman. His heavily and exaggeratedly accented speech is written phonetically (for example, "twenty-five cents" is written as "twinty-foive cents"). Many readers, especially those unfamiliar with an Irish accent, are likely to find Flannery's speech difficult to understand.
Mr. Morehouse arrives at the office of the Interurban Express Company at the train station in the village of Westcote. He has come to collect two guinea pigs. The guinea pigs are a present for his son which have been sent by rail from the city of Franklin. The charge for sending domestic pets from Franklin to Westcote is twenty-five cents for each animal. Mike Flannery, who runs the office, believes that guinea pigs are Italian pigs. He therefore insists that the higher rate charged for sending pigs from Franklin to Westcote, thirty cents for each animal, applies. The company's rule book states that if there is any doubt regarding which of two rates applies, the higher rate is to be charged. Mr. Morehouse refuses to pay the sixty cents. He leaves the two guinea pigs with Flannery and goes home to write a letter of complaint to the president of the Interurban Express Company.
A few weeks later, Mr. Morehouse receives a reply, telling him to write to the Tariff Department. Mr. Morehouse does so. Mr. Morgan, the head of the Tariff Department, finds out about the problem. Mr. Morgan believes that the guinea pigs have probably died of starvation by this time. He writes to Flannery, asking about their current condition. Flannery replies that the guinea pigs seem to be healthy. There are now eight of them, the original two having had six children, and they eat a lot. Flannery has spent $2.25 on cabbages to feed them. Flannery is told to go to Mr. Morehouse's home to claim the $2.25 from him. Flannery is not surprised when Morehouse refuses to pay and slams the door in his face.
Mr. Morgan asks the president of the Interurban Express Company if he thinks guinea pigs are pigs. At first, hoping to charge the higher rate for transporting them, he says that they are pigs. When Morgan says that he thinks guinea pigs are more like rabbits, the president has to agree with him. He writes a letter to the eminent zoologist Professor Gordon, asking for his opinion. Unfortunately, Professor Gordon is away on an expedition to the Andes and it is a long time before the letter is forwarded on to him. By that time, the president, Mr. Morgan and Mr. Morehouse have forgotten all about the guinea pigs.
The number of guinea pigs which Flannery has to take care of has increased to thirty-two. He spends half of his working hours looking after them. He contacts head office, asking for permission to sell some of them. He receives a reply, telling him that he cannot sell any of the guinea pigs because they are not the property of the Interurban Express Company. He asks again when the number of guinea pigs has increased to one hundred and sixty. Again, he is told that he cannot sell any of the animals.
The president of the Interurban Express Company receives a reply from Professor Gordon. The professor's letter clearly states that guinea pigs are not a kind of pig. It also says that guinea pigs multiply rapidly. A letter is sent to Flannery from the Audit Department. it tells him to take the one hundred and sixty guinea pigs to Mr. Morehouse and charge him twenty-five cents for the delivery of each animal. By this time, the number of guinea pigs that Flannery has to care for has increased to eight hundred. The animals take up most of his office. He has employed six boys to help look after them and spent sixty-four dollars on cabbages. After Flannery informs the Audit Department about the situation, he is at first sent a letter telling him to take all eight hundred guinea pigs to Morehouse, although by the time that Flannery receives the letter, the number of guinea pigs in his care has increased to four thousand and sixty-four. He later receives a telegram which tells him to take just two guinea pigs to Mr. Morehouse.
When Flannery arrives at Mr. Morehouses's home, he finds it empty. Mr. Morehouse has moved away and nobody in the village knows where he has gone. Flannery writes to the Audit Department, asking what to do. He is advised to send the consignment to head office. Flannery begins the process of sending thousands of guinea pigs to head office. He continues to do so, even after he has been told to stop.
An inspector from head office arrives in Westcote with orders to make Flannery stop sending more guinea pigs. He finds Flannery and the six boys loading a train full of the little creatures. Flannery is relieved that the guinea pigs are now almost all gone. He says that, in future, he will always charge twenty-five cents for the transportation of all animals.
- Sound files of public domain audiobooks of "Pigs Is Pigs" from LibriVox: