Scientists in China have discovered two fossil mammals from the age of dinosaurs. One still had in its stomach the remains of its last meal--a baby dinosaur. The other mammal, the size of a modern dog, is by far the largest mammal known from this period.

These fossils are cool for a bunch of reasons. Complete skeletons are rare, and skeletons with stomach contents preserved are extremely valuable: they tell us who ate who, and how animals related to each other and to their environment.

And that's what's really interesting. We've known for a long time that
mammals and dinosaurs lived side-by-side. But before this all the
mammals we'd found were tiny, the size of chipmunks or shrews. They hid
during the day and came out at night to eat insects and seeds. The common
thinking was that primitive mammals couldn't compete with dinosaurs, and it
wasn't until the dinos went extinct that mammals could come out of the shadows
and grow large.

But now we have large mammals from dinosaur days. And they weren't timid
shrews--they were active hunters. Not only that, they hunted for
dinosaurs! Some scientists think these new predators may have influenced
dinosaur evolution.

What do YOU think?

  • What do the fossils tell us about the relationship between animals?
  • What do the fossils tell us about evolution, both of mammals and of dinosaurs?
  • Is it time to abandon our old assumptions? What new explanation should take its place?
  • Should the Science Museum do an exhibit on this?

Your Comments, Thoughts, Questions, Ideas

Christopher P.'s picture
Christopher P. says:

It is a very exciting time, China has been a hot bed of paleontology for the last 15+ years. I really dont think that finding a large mammal from the time of dinosaurs is all that unexpected, however it gives an interesting window on animal behavior. The first mammmals were rather large. Definately the animals that mammals evolved from were large carnivors (look at dimetrodon), evidense until now was just lacking for such a relationship.

posted on Thu, 02/10/2005 - 2:42pm
Anonymous's picture
Anonymous says:

right.... sure they were meat eaters but a dinosaur (a baby)!

posted on Wed, 12/05/2007 - 2:13pm

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