T. rex sleeping and Didelphodon hunting

Tyrannosaurus rex Sleeping

This is a sub-adult T. rex sleeping.  You could add stars and a moon in the sky if you want.  The T. rex pictured is a sub-adult, not quite a full grown adult.  It laid down on some ferns for a comfortable sleep.  Yesterday I drew a Triceratops calf and mother sleeping.  I decided to do a sleeping T. rex today.  The picture at the bottom of today's post is more complete. . . I explain why below.

I thought about it and decided to add a couple of things to the above drawing and scan and post the update.   .   .  .   .  OK, I just did so.  I added a moon and a few stars and 2 small mammals.  There WERE mammals living with the dinosaurs, but they stayed small to avoid being killed and eaten. . . or to avoid being stomped on.  The mammals of the Mesozoic were all fairly small and could burrow into the ground for safety. 

Still, Didelphodon vorax, a marsupial mammal from T. rex's time, was no cowering coward.  It had very robust canine teeth.  A new study indicates that it had a bite force stronger than even the hyena.  In fact, Didelphodon's bite force was the strongest of any known mammal.  It was about the size of a modern Virginia opussum.  Yet it had a very robust skull and a terribly powerful bite and clearly was a predator.  Even some small dinosaurs would have been at risk.  It was probably active at night. . . it was nocturnal.  This would give it some safety from larger dinosaurs.

Didelphodon vorax Skull photo

In the past some paleontologists have speculated that perhaps the growing mammal population was eating dinosaur eggs at the end of the Cretaceous Period.   Now it appears that perhaps some mammals could have preyed on dinosaur young as well as their eggs.   There was a marked decline in the number of dinosaur species in Montana over the last several million years in the late Cretaceous Period.  Maybe Didelphodon was preying on the young of the dinosaurs.  Of course, the Meteorite is what finished off the large dinos.   Both Didelphodon vorax and Tyrannosaurus rex lived in what is now Montana during the late Cretaceous.

The new study about Didelphodon vorax was by the Burke Museum and the University of Washington paleontologists.  They also found that marsupials appear to have evolved in North America and moved south.

T. rex sleeping and Didelphodon hunting

Didelphodon is on the right and its prey is hiding under a fern on the left.   If you take the two pictures together, the first is a couple of hours earlier in the night and the second is later when Didelphodon comes along hunting for small prey.  Didelphodon would have to be careful to not wake up the nearby T. rex when it caught the prey mammal.