Red Boned Fossils are fossils that give the player a 25 point bonus if sucessfully cleaned (even if it would result in a score over 100). The only way to find them are to exchange Donation Points for them or to accept a Fossil Battle challenge when the player digs up a Dark Fossil Rock, as they usually contain Red Boned Fossils. Red Boned Fossils may also be found normal Fossil Rocks, though this is rare. An indicator of this would be if the player is challenged by a Fossil Fighter after digging up a normal rock. The chance of this is 50%.
In Fossil Fighters: Champions, the chance of finding a Red-boned Fossil in a fossil rock obtained by fighting a Fossil Fighter has been increased to 100% of the time. These fossils still remain rare, however.
There are several fossils that are only available as Red Boned Fossils.
Fossil Fighters: Champions
These can also be purchased as regular fossils: