Finding animal droppings in your attic, basement, or garage is a stomach-turning discovery. However, before you sweep it up in disgust, take a closer look. Those droppings are the most reliable evidence you have to identify the intruder.

Different animals leave very distinct signs. Knowing whether you are dealing with a mouse, a rat, a raccoon, or a bat is critical because the removal strategy—and the health risks—vary significantly for each.

Here is your guide to becoming a scat detective.

Safety First: The Golden Rule

STOP. Do not touch, sweep, or vacuum animal droppings without protection.

Dried animal waste can release microscopic spores, viruses, and parasite eggs into the air when disturbed.

• Hantavirus: Carried by deer mice, this respiratory disease can be fatal.
• Histoplasmosis: A fungal infection of the lungs caused by spores in bat and bird guano.
• Raccoon Roundworm: A parasite that can cause blindness and brain damage in humans.

Before inspecting:

1. Wear an N95 respirator or better. A simple dust mask is not enough.
2. Wear rubber or latex gloves.
3. Do not use a standard household vacuum; it will blow pathogens into the air.

1. Mice Droppings

This is the most common find.

• Size: Small, about 1/8 to 1/4 inch long.
• Shape: Pointed at both ends. They look like grains of black rice.
• Quantity: Mice are prolific poopers. One mouse can leave 50-75 pellets a day. You will find them scattered everywhere—along walls, in cupboards, and near food sources.
• Freshness: Fresh droppings are dark and soft. Old ones are grey and crumbly.

2. Rat Droppings

Rats are larger, and so is their waste.

• Size: Larger and thicker, about 1/2 to 3/4 inch long.
• Shape: Norway Rats: Capsule-shaped with blunt ends. Roof Rats: Slightly more spindle-shaped with pointed ends. Think the size of a raisin or an olive pit.
• Location: Rats tend to leave droppings in groups along their travel paths (runways) or near feeding areas.

3. Bat Guano

Bat droppings are often mistaken for mouse droppings because they are similar in size and color (dark brown/black). However, there are two key differences:

• Texture: Bat guano is made of insect parts. If you shine a light on it, it will often sparkle or glitter due to the insect wings.
• The Crush Test: (Do this with a stick, not your hand). Mouse poop is hard and putty-like. Bat guano is dry and will crumble instantly into a fine dust.
• Location: You will find guano in piles directly underneath where the bats are roosting (usually near the peak of the attic or under a vent). It won’t be scattered along baseboards like mouse poop.

4. Raccoon Droppings

This is a serious biohazard.

• Size: Large, 2-3 inches long. Roughly the size of a small dog’s droppings.
• Shape: Tubular with blunt ends.
• Content: Because raccoons are omnivores, you will often see undigested seeds, berries, or corn in the scat.
• Location: Raccoons use communal toilets called “latrines.” They will pile their waste in one specific spot—often on top of insulation, on a flat roof, or at the base of a tree.
• Warning: Raccoon latrines often contain roundworm eggs. Professional remediation is strongly recommended.

5. Opossum Droppings

• Size: Similar to raccoons but often more curled or segmented.
• Shape: Can be irregular.
• Smell: Opossum waste is notoriously foul-smelling compared to other wildlife.

6. Squirrel Droppings

• Size: Similar to rats but slightly shorter and rounder.
• Shape: Often described as “bean-shaped” or rounded.
• Color: Can vary from brown to tan to red depending on what they are eating.
• Location: Squirrels often defecate randomly, but you may find concentrations near the entry point.

What To Do Next

Once you have identified the animal, you can formulate a plan.

• Mice/Rats: Snap traps and sealing small holes.
• Raccoons/Opossums: Live cage traps and heavy-duty exclusion.
• Bats: One-way exclusion devices (no traps!).

If you are unsure, or if the mess is extensive, call Critter Removal of Louisville. We can identify the species, remove the animals, and perform a full attic decontamination to remove the hazardous waste and restore your home’s safety.