The Daltons are fictional who regularly appear in the Lucky Luke comic book series. They were created by artist Morris and writer René Goscinny. They are loosely inspired by the real-life Dalton Gang, and billed as their cousins. While the original Dalton brothers are depicted as evil and successful these Daltons are depicted as less skillful and more prone to fighting between the siblings. All four Daltons are depicted as identical except for in height, with the oldest brother Joe being the shortest and the youngest brother Averell being the tallest.
Their storylines often begin with the gang escaping from prison, followed around by prison dog Rantanplan as they try to carry out whatever plans Joe Dalton, or their mother Ma Dalton, has in mind. Usually the gang ends up back in jail at the end of the story as Lucky Luke rides off into the sunset. The characters have appeared both in the comic book version of Lucky Luke as well as the animated series and were also part of the spinoff series Rantanplan and starred in their own short story animated show that made its debut in 2010.
The "real" Daltons — Bob, Grat, Bill and Emmett — appear in the Lucky Luke adventure "Hors-la-loi" written and drawn by Morris in 1951. Morris drew them absolutely identical in everything but height, which varied from Bob, the shortest and most dangerous, to the tallest Emmett. At the end of the story the Daltons are all killed in a raid in the town of Coffeyville, Kansas where two of the real-life Daltons, Bob and Grat, were also killed (In real life, Emmett was wounded in the Coffeyville shootout and subsequently jailed, while Bill Dalton did not take part in the raid).
In the most recent Lucky Luke story, history is being retold again as Emmett is indeed shown to have survived the Coffeyville shoot out and has since fathered a son which the cousins Daltons are now laying claim to. Just as Averell takes after Emmett (Both being the tallest member of the gang) Emmett Jr. takes after Averell in him being an enormous glutton and drawn to Averell's childish nature.