Traces of dino blood, soft tissue found even in junk bones
Discovery gives scientists new places to search for clues to when warm-bloodedness evolved
![traces of dino blood](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/06/ay_dinobloodhero_free.jpg?fit=860%2C460&ssl=1)
DRIED BLOOD A scanning electron micrograph of a sliver of a theropod’s toe claw reveals oval-like structures that resemble the red blood cells seen in living birds. The colors correlate to density: less dense, carbon-based material appears red and denser mineralized material appears green.
S. Bertazzo et al/Nature Communications 2015