How to know it is this one
Slim, dark grey to near black, with a tail longer than its head and body combined, large thin ears and a pointed nose. That tail is the quickest identifier. The brown rat, by contrast, is heavier and blunt-nosed with a tail shorter than its body, and stays at ground level.
Where it gets in
High. Black rats are excellent climbers and travel along cable runs, pipework, boundary walls and palm trunks, entering at roof level — through gaps at the roofline, broken vents, spaces where air conditioning pipework passes through a wall, and unsealed service penetrations. Once inside they use false ceilings and voids as runs.
This is why a property can be entirely clean at ground level and still have rats.
The signs
- Droppings about 10mm, spindle-shaped with pointed ends, along runs and in ceiling voids
- Scratching or scurrying overhead, most often shortly after dark
- Gnaw marks on cable insulation, plastic pipe and stored packaging
- Dark smear marks where fur repeatedly brushes a beam or pipe
- A strong ammonia smell in an enclosed void
Why proofing comes first
You can clear every rat from a property and have new ones within a fortnight if the entry points are still open. They arrive from neighbouring plots, construction sites and drainage. So the work is two halves: reduce the population with trapping and tamper-proof bait boxes, and seal what lets them in — gaps at the roofline, damaged vents, service penetrations, door sweeps that no longer meet the floor.
If there is a smell and nothing visible
Something has usually died inside a wall cavity or ceiling void. It needs locating and removing — left alone it becomes a fly and beetle problem within about a week.