Treadwell spent the early part of each season camping on the "Big Green", an open area of bear grass in Hallo Bay on the Katmai Coast. He called the area the "Grizzly Sanctuary". Treadwell was known for getting extremely close to the bears he observed, sometimes even touching them and playing with bear cubs. In his book, though, he claimed that he was always careful with the bears and actually developed a sense of mutual trust and respect with the animals. He habitually named the bears he encountered, and consistently saw many of the same bears each summer, so claimed to build a standing relationship with them.