T. rex tissue preserved

Paleontologists who chipped a 70-million year old Tyrannosaurus rex fossil out of sandstone say they have found soft tissue including what appears to be blood vessels.

The discovery was made when they broke the giant creature's thighbone in order to fit in onto a helicopter to transport it.

Lead researcher Mary Higby Schweitzer of North Carolina State University describes the material inside the fossilized bone as transparent, flexible cell-like structures.

"The vessels and contents are similar in all respects to blood vessels recovered from ... ostrich bone," the team reported in Friday's issue of the journal Science.

Experts believe studying the soft tissue may help answer questions about whether dinosaurs were cold blooded or warm blooded, as well as clarifying their relationship to living animals such as birds.

The fossil was retrieved at a dig in Montana.

It is rare for paleontologists to find soft tissues in fossils.

The team's next step is to see if they can identify DNA in their samples.