But they're sleeker, with black or brown fur, a pointed nose, big ears, and their signature long, hairless tail ... three main warning signs that you may have a roof rat infestation.

Techniques for blood collection from the rat include puncture of the heart, retro-orbital plexus, jugular vein, saphenous vein, tail blood vessels, carotid artery, abdominal aorta, and vena cava.