Bison once dominated the Great Plains but were nearly wiped out by hunters in the 1800s. Now scientists are learning that bison's presence improves plant and wildlife diversity on the prairies.
We can't return degraded landscapes to their original state but we can change the way people relate to their local environments.
DNA analysis suggests that a newly discovered species of bison roamed Europe some 17,000 years ago - as prehistoric cave artists were trying to tell us all along.
The case for why this dog-sized rather laid-back herbivore should be reintroduced to the UK.