Identifying and Responding to Wildlife Odors

Is the odor coming from the wall? Use of a fiber optic scope allows you to see inside the wall without making large holes to investigate.

Some Causes of Odors:

1. Feces/Urine of the animal

Some animals like bats, raccoons, and flying squirrels urinate and defecate in buildings. If these nuisance animals are not removed, the fecal/urine material can build up and cause a stench. Realize, however, that you can have feces/urine in your home and without any noticeable smell. Odors can be dissipated by attic vents and shielded by thick insulation.

Before removing any animal feces, urine, or contaminated material, be sure you understand the potential biohazards associated with removal. Protect yourself by wearing appropriate gloves and respiratory protection. For more information, see diseases.

2. The animal

Other times, the odors are caused by the animals themselves. Animals like raccoons and squirrels have their own odors that, over time, can become more noticeable in a home. Other times, these animals smell after they die in the wall or attic. Often, animals die because of the use of toxicants.

Signs that the smell emanated from a dead animal:

  • flies.
  • smell is faint and gets progressively stronger and lingers for days to weeks. This is especially true of skunks that have died under decks and sheds.
  • putrid odor.

Don’t be surprised at the amount of odor caused by an animal as small as a mouse.

3. Wastewater pipes

Broken or cracked wastewater pipes have been known to cause persistent or intermittent odors over long periods of time. While not a common source of odor, it must be considered if other options are ruled out.

4. Stinkhorn

Stinkhorn is a fungus that gives off a powerful odor. Learn more about them here.


Strategies for responding to and even preventing these odors:

  • Try to find the cause/source. Use caution when looking as other living animals may be around. Also, you should wear appropriate protective equipment in case you find a carcass. Protective clothing should include, but not be limited, to 1. rubber gloves inside leather gloves; 2. old clothes; 3. Properly fitted HEPA filter face mask.
  • Increase air flow. Air flow dissipates the smell.
  • Spray deodorant. This doesn’t have to be anything special. What you like to smell is the most important factor. Be careful about what surfaces you spray the deodorant on as it may cause discoloration.
  • Epoleon Corporation makes a number of deodorizing products that have a following in the Wildlife Control Community, with good reports.
  • We don’t recommend tearing a hole in the wall. It is easy to be fooled and be one stud away from the source of the problem, requiring you to make two holes instead of one. Avoid using poisons to control mice as the odor problem can happen again, although it is rare.
  • Remember that the odor will go away eventually. As soon as the carcass dries out the odor will disappear, so the need to dry out the carcass is critical. Larger carcasses will take more time to dry out. Of course, if you can remove the carcass (using proper protective equipment and recognizing that there may be infectious agents in the carcass), then the odor will go away even faster.
  • We have heard of ozone-type deodorizing and/or ionizing devices to dissipate odors, but have not been able to  get a firm scientific handle on the validity of their claims. Be cautious about such claims from those who sell these machines. Ask for references.
  • For skunk odor questions, see the University of Nebraska publication on removing skunk odors.