Explanation:

- The passage describes characteristics of the Small Indian Mongoose.

- The context of blank no. 5 is key. It addresses a surprising fact about the mongoose.

- Option 1: "Instead" - This implies a replacement or alternative, which doesn't fit the context.

- Option 2: "Apart" - This suggests a separation or difference, not well-suited to the context here.

- Option 3: "Often" - This suggests frequency, which doesn't fit since the sentence does not focus on a frequent event.

- Option 4: "Despite" - This shows contrast and highlights that mongooses, although similar looking, are not rodents.