What is the typical diameter of a Norway rat burrow opening?

What is the typical diameter of a Norway rat burrow opening?

• A. 1-2 inches
• B. 2-4 inches
• C. 3-5 inches
• D. 4-6 inches

Answer: (B)

A Norway rat burrow opening is typically two to four inches in diameter. This size matches the body dimensions of an adult rat big enough for the head and shoulders to pass through while keeping the tunnel practical and structurally stable. In the field, you’ll often see circular entrances with surrounding dirt mounds and multiple linked openings, reflecting the network of tunnels used for travel, nesting, and escaping threats. Smaller openings are more characteristic of other species like house mice or roof rats, while openings much larger than four inches are unusual for Norway rat burrows.

A Norway rat burrow opening is typically two to four inches in diameter. This size matches the body dimensions of an adult rat big enough for the head and shoulders to pass through while keeping the tunnel practical and structurally stable. In the field, you’ll often see circular entrances with surrounding dirt mounds and multiple linked openings, reflecting the network of tunnels used for travel, nesting, and escaping threats. Smaller openings are more characteristic of other species like house mice or roof rats, while openings much larger than four inches are unusual for Norway rat burrows.