First appeared in the 1971 children's book The Lorax. The swans are long-tailed and floppy-winged birds with orange bodies and yellow heads and beaks. They fly through the air, swim in the water, sit the Truffula trees, and their calls ring out in space. After the smog from the factories pollutes the air, they are forced to leave in a sad exit flight.
2013, in computer animated Lorax movie produced by Illumination Entertainment, the swomee swans appearance has changed to more yellowish-orange bodied with darker orange heads. Their odd plumed neck rings are more visible.
HistoryWhen The Once-ler arrives in their homeland, he identifies them and notes their song ringing out in space. Later, smog comes out of the Once-ler's factory's chimney, which, according to the Lorax, got into their throats and made them lose their ability to sing, so they flew away.
In the movie, the Once-ler arrives and unpacks his bag while singing a song. However, when he accidentally throws a mallet at one, it gets angry and threatens him with the mallet. When the Once-ler protects himself from Pipsqueak, who was about to hit him, with a bag of marshmallows, Pipsqueak rips open the bag and marshmallows fly out all over the place, and the swomee swans, along with the other forest animals, eat them.
A baby swomee swan (swomee cygnet) plays Go-fish with a Humming Fish but keeps eating the Humming Fish's cards.
After the Lorax attempts to float the Once-ler down the river and then saves his life upon realising there was a waterfall, the animals and the Lorax find one of the Once-ler's socks and come to return it to him, but he's asleep so they watch him as they think he looks cute and then they fall asleep. When they wake up, a swomee swan lays an egg in the Once-ler's bowl, which he finds disgusting.The Once-ler then discusses with the baby swan on whether or not he's bad, then sings How Bad Can I Be?, during which a swan loses its feathers due to the smog.