While my focus these days has narrowed substantially from the original book concept–how the world’s apex predators went from T. rex to cats–news this week about finding the biggest dinosaur tracks ever caught my eye.

It was sauropods walking in Jurassic mud that is now stone in Scotland. Trackways like this are the only tangible evidence we have of long-extinct animals as they existed as living beings at a precise moment in geologic time.

Looking at tracks is a really exciting visceral experience, though scientists generally don’t get this wonderfully enthusiastic:

Environments often change dramatically down through time, but Utah back in the day actually was a desert, though perhaps dinos left these tracks during one of the high-sea-level times.

Things were a lot wetter in Middle Jurassic Britain.

Those huge tracks that recently made headlines came from sauropods wading in one of the many lagoons that pooled together on a Mid-Jurassic British coast where shallow seas and river deltas came together.

Tyrannosaurs were theropods. Sauropods were veggie dinosaurs–the biggest ones of all.

Can you imagine how much vegetation a herd of those giants went through in one day? Scientists are working on it.