From Nookipedia, the Animal Crossing wiki
The Motherly Statue is a sculpture first introduced in Animal Crossing: New Leaf. This piece is based on the Capitoline Wolf, whose age and origin are subjects of controversy. The bronze sculpture is based on the legend of Rome's foundation, and features Romulus and Remus, and the she-wolf who cared for them as infants. The name Capitoline comes from the fact that the statue has resided in Capitoline Hill since 1471.
According to legend, a prophecy foretold that the twins Romulus and Remus would overthrow their great-uncle Amulius. Upon discovering the prophecy, Amulius overthrew his brother Numitor, who was the grandfather of the twins, and had the twins cast into the Tiber River. However, they were rescued by a she-wolf who cared for them until a herdsman named Faustulus found and raised them. When Romulus and Remus matured, they decided to create a city together, Rome, but as a result of a conflict between them, Romulus killed his brother Remus.
In New Leaf, the statue is displayed in the first Artwork room, in the northeast quadrant.
In Animal Crossing: New Leaf, if only one of the twins are featured in the statue, then it is a forgery.