Black-tailed prairie dogs at Roberts Prairie Dog Town, Badlands National Park, South Dakota, USA (© Greg Vaughn/Getty Images)

If you think small creatures can't make a big impact, you clearly haven't met the residents of Roberts Prairie Dog Town in Badlands National Park, in South Dakota, United States. These black-tailed prairie dogs are tiny, furry and endlessly entertaining. The town is one of the park's largest prairie dog colonies, where hundreds of these social rodents scurry, dig and 'bark' at passing visitors. Each prairie dog has a role—lookouts scan for predators while others maintain intricate burrow systems that can stretch up to 10 metres in length.