Which physical characteristic helps to identify a roof rat?

The long, thin tail is a distinctive physical characteristic that helps identify a roof rat. Roof rats, also known as black rats, have tails that are typically longer than their bodies, which gives them a sleek and agile appearance. This length is not only an identification feature, but it also aids their climbing ability, allowing them to navigate trees, rooftops, and other elevated structures effectively.

In contrast, the other characteristics provided do not specifically identify roof rats. For example, short stubby ears are more characteristic of other types of rodents, while a small body size may apply to various rodent species and does not uniquely distinguish roof rats. Grey fur is more associated with other species like Norway rats, which can cause confusion. Each of these other characteristics lacks the specificity needed to accurately identify the roof rat, making the long, thin tail the most reliable distinguishing feature.