Like their bison cousins, aurochs stood their ground to defend against threats rather than fleeing, making them risky to approach. Aurochs were not only massive, but massively successful as a species.

Big herbivores such as bison or aurochs-proxies are one example but the rewilders’ real poster boy is the beaver. Gow likens this semi-aquatic rodent to a pilot light in a boiler. He says ...