Grandfather Paradox

Marooned in the present, their only hope for the future lay in the past.

But first there was still the small matter of staying alive.  The planet they were marooned on was crawling with bird-beasts, immense parrotlike carnivores that stood two meters tall, weighed upwards of fifty klogs, and had a giant scooped beak like a pelican.  They normally swallowed their prey whole, though not before crushi...