National Geographic asked Dr Thomas Holtz, a dinosaur paleontologist at the University of Maryland’s Department of Geology, to give a professional's reaction to Will Ferrell's new film Land of the Lost.
It includes this explanation as to why you could not douse yourself in dinosaur urine, even if that was your thing:
[He] assumes that if he douses himself in hadrosaur urine …
And a hadrosaur is?
A duck-billed, plant-eating dinosaur.
Now, back to the urine.
He assumes that dousing himself will keep the predators from going after him. Everyone else would think the urine would attract the predators, which it does. They sniff him out easily. It’s a good gag, but the premise isn’t based on biology.
Dinosaurs wouldn’t pee lots and lots and lots of urine. They’re part of this group of reptiles called diapsids. Today’s diapsids are lizards, snakes, crocodiles, and birds. The way they get rid of nitrogenous wastes from their kidneys is not by peeing lots of liquid. It’s by excreting this white sticky paste. So when you find the white paste on your car, the bird hasn’t pooped on it; it’s peed on it. That way they conserve a lot more liquid than mammals or amphibians.
The pee mistake has been made before?
Even Walking with Dinosaurs got this infamously wrong. In one scene in this 1999 BBC documentary, a big predator marked its territory by peeing all over it. Mammals do that because we pee a lot. Reptiles wouldn’t.