Scientists have been trying to explain exactly how some soft tissue on a 68 million year old T Rex skeleton could have survived millions of years without rotting away. The question has been burning in the minds of researchers since 2005 when an adolescent T Rex skeleton was discovered in Montana that had soft tissue preserved inside the leg. At first, scientists believed that the soft tissue had to be caused by some sort of later bacterial infection.
Researcher Mary Schweitzer said:
What we found was unusual, because it was still soft and still transparent and still flexible.
When the soft tissue was discovered, scientists believed that proteins that make up soft tissues would degrade in less than 1 million years under even the best conditions. In many instances, those soft tissues would be destroyed within weeks thanks to microbes. The soft tissue discovered inside the leg bone of the T Rex was collagen and the scientists think they have finally discovered what allowed the tissue to survive millions of years.
The reason the tissue remained soft is believed to be iron, which is an element that is abundant inside the body of animals of all sorts. When the dinosaur died, the iron was released from molecules that it was bound to while the dinosaur was living, generating free radicals.
The free radicals cause proteins and cell membranes to tie in knots. They basically act like formaldehyde.
The scientist said that dinosaur soft tissue was found to be closely associated with iron nanoparticles in the T Rex and another dinosaur called a Brachylophosaurus canadensis discovered with soft tissue intact. The team tested the theory that iron was responsible in the lab using modern ostrich blood vessels. One group of blood vessels was soaked in water and another in an iron rich liquid made of red blood cells. The water group was a mushy mess in days, but the iron soaked blood vessels were recognizable after two years at room temperature.