Note: The following article was written around 2001 and was updated for the 2011 edition of ISO’s HO-3 policy form, so the information in this article is largely up to date, though it is provided primarily as an historical analysis of the subject matter and an exercise in determining the meaning of words when there is semantic ambiguity in insurance contract language.


What is a “Vermin”?

Mice, roaches, snakes, turtles, bats, pigeons, raccoons, skunks, carpet beetles, squirrels. What do these critters have in common? They have all been cited as “vermin” in claim denials. In this article, we’ll look at these varmints, examining a number of court cases, in an effort to determine what’s a “vermin.”


Here’s a question received by the Big “I” Virtual University’s “Ask an Expert” service from a state insurance department investigator:

“The wind blew out a ‘plug’ at the end a roof vent and bats got inside causing considerable damage to the insulation. The insureds did not hear or see anything, however, eventually noticed a smell and finally found the cause. No one has a clue as to why the ‘plug’ blew out and the insurance company is not disputing that part of the claim.

“The insuring policy has an exclusion for losses caused by birds, vermin, rodents, insects or domestic animals. The company has made the determination that bats fall under the definition of vermin.

“In checking with a standard dictionary, vermin is defined as: ‘(1) any of various small animals or insects that are destructive, annoying, or injurious to health, such as cockroaches or rats. (2) Any of various animals that prey on game, as the fox or weasel.’

“Additionally, the same dictionary defines a bat as an animal. We think the company has made the right call, but were wondering if your experts could offer more to go on, either in support of claim payment or the denial. Thanks for your time.”

Thanks for the question, it’s a good one…and one we’ve all heard dozens of times. Our “Ask an Expert” service must get a vermin question at least once a month, like this one just received after the initial publication of this article:

“Most policies exclude damage caused by ‘vermin’ but I haven’t found a policy that contains a definition of ‘vermin.’ One of my companies takes the position that the definition of ‘vermin’ would include, amongst other things, rats, foxes, otters, badgers, weasels, minks, ferrets, muskrats, and skunks. Is there any place I can go to get a scientific, or at least informed, definition of the word ‘vermin’? Something better than a dictionary definition.”

To make a long story short, the unanimous (which is somewhat unusual) opinion of the VU faculty is that a bat is NOT a vermin. We’ve had this question come up many times in claims denied due to damage by raccoons, skunks, snakes, turtles, and other critters…each time on the basis of the exclusion for “vermin.” We’ve yet to find a court case (with one minor exception discussed below) that sided with the insurer.

Not all animals are vermin. In fact, since the policy excludes “domestic animals,” damage caused by any non-domestic animal is covered…unless that animal is a bird, rodent, insect, or “vermin.” [Note: Unlike this older or proprietary HO policy, the current ISO HO-3 policy excludes “animals owned or kept by an ‘insured’,” not “domestic animals.”] So, the issue is, what is a “vermin?” Since the term is not defined in the policy, we must look to other sources such as dictionary definitions and court cases.

Of all the court cases I’ve seen, with one exception (Christ Episcopol Church of Bastrop, LA v. Church Insurance Company, 731 So. 2d 1071, Louisiana Court of Appeals, 1999), EVERY court that has reviewed this term has found it to be ambiguous. In the one case cited above (and below) where the exclusion was permitted, the damage was caused by mice and rats, which are conceded to be “vermin” by just about any accepted dictionary definition (in addition, the policy expressly excludes rodents). The same can’t be said for other animals such as bats.

Here are some dictionary definitions that demonstrate the diversity of what “vermin” means:

The American Heritage® Dictionary of the English Language, Fourth Edition, 2000:

Vermin…Various small animals or insects, such as rats or cockroaches, that are destructive, annoying, or injurious to health.

In the case of Sincoff v Liberty Mut. Fire Ins. Co., 11 NY2d 386, 390 (NY Court of Appeals, 1962), the court cites the following definitions:

Webster’s New International Dictionary (2d ed., Unabridged, 1956) defines the word vermin as “[noun]…1. Any noxious, mischievous, or disgusting animal…2. Specif.: Such an animal, or esp. such animals collectively, when of small size, of common occurrence, and difficult to control. Various insects as flies, lice, bedbugs, fleas, etc., various mammals, as rats, mice, weasels, etc., and sometimes such birds as hawks and owls, are classed as vermin.”

Funk and Wagnall’s New Standard Dictionary, at page 2644, defines vermin as “(1) Obnoxious insects, especially parasitic ones, as lice, fleas, or bedbugs. (2) [Eng.] Animals destructive to game, as weasels, polecats, badgers, otters, hawks, or owls. (3) [Austral.] Animals injurious to vegetation or to domestic animals.”

In England, the word “vermin” has been defined by statute as follows: “‘vermin’ includes bugs [bedbugs], fleas, lice and itch mites and their eggs, larvae and pupae”. (Public Health [London] Act, 1936, 26 Geo. 5 & 1 Edw. 8, ch. 50, § 304, subd. [1]; 15 Halsbury’s Statutes of England [2d ed.], p. 1034). These creatures, constituting “vermin” under the English definition, all are parasitic in nature.

The Encyclopedia Americana (Vol. 28 [1955 ed.], pp. 16-17) defines “vermin” as: “A term comparable to ‘weed’ signifying small animals obnoxious in some way to human plans and operations. It has been applied to rats, mice, gophers, weasels, and other mammals; such insects as fleas and lice and at times to hawks, owls and other birds.”

In the case of North British & Mercantile Insurance Company v. Mercer, 211 Ga. 161; 84 S.E.2d 570; (Georgia Supreme Court 1954), the court says:

The smaller dictionaries define vermin to mean “noxious, mischievous or mean animals or insects.” The larger New International Webster’s Dictionary (2d ed.), after giving in substance the above meaning, proceeds to specify or particularize by naming the class of animals and insects to which it refers “as flies, lice, bedbugs, fleas, etc., various mammals, as rats, mice, weasels, etc.”

In the case of Stafford L. & Doris Jones v. American Economy Insurance Co., 672 S.W.2d 879; (Texas Court of Appeals, 1984), the court cites the following definition:

Webster’s New Collegiate Dictionary, 1301 (1974) defines “vermin” as “small common harmful or objectional animals (as lice or fleas) that are difficult to control…birds and mammals that prey on game…an offensive person.”

In the case of Christ Episcopol Church of Bastrop, LA v. Church Insurance Company, 731 So. 2d 1071; (Louisiana Court of Appeals, 1999), the court cites these definitions:

Webster’s Revised Unabridged Dictionary (G. & C. Merriam Co., 1913) defines vermin as: “[Pg 5] 2. A noxious or mischievous animal; especially, noxious little animals or insects, collectively, as squirrels, rats, mice, flies, lice, bugs, etc.”

The American Dictionary of the English Language (Webster, 1828) also listed rats and mice as being “vermin.”

American Heritage Dictionary of the English Language (Houghton Mifflin Co., 2d college ed. 1976), defines vermin as: “1. Any of various small animals or insects that are destructive, annoying, or injurious to health, cockroaches or rats.”

The Random House Dictionary of the English Language, Unabridged (Random House, 2d ed. 1987), defines vermin as: “1. Noxious, objectionable or disgusting animals collectively, esp. those of small size that appear commonly and are difficult to control, as flies, lice, bedbugs, cockroaches, mice, and rats.”

So, as you can see, the dictionary definitions vary widely, depending on what dictionary you’re looking at. For that reason, most courts have found that there is no universally accepted definition of “vermin,” so, therefore, the term is ambiguous.

The only common definition we can find is that vermin are, primarily and collectively, very small, noxious creatures such as bugs, lice, etc. or mice, rats and similar rodents. Oxford English Dictionary (Oxford Univ. Press, 2d ed. 1991) shows that the term “vermin” as it has been used regularly over the centuries, starting at least in 1513, has been accepted to include rats and mice.

The word “vermin” comes from the Latin vermis, which means “worm.” That would imply that the origins of the word “vermin,” dating to at least the early 16th century principally involve small, insect-like animals. Over the centuries, with scourges of mice and rats in Europe, that class of animals has been added to the definition.

In addition to the dictionary definitions above, below is a real quick analysis of the logic used in several court cases, including links to more detailed versions:

North British & Mercantile Insurance Company v. Mercer, 211 Ga. 161, 84 S.E.2d 570 (Georgia Supreme Court 1954):

In this case, damage was caused by squirrels. Although squirrels, like rats and mice, are in the order of rodentia, the court felt, citing a dictionary definition, that not all rodents are “vermin,” implying that, while rats and mice probably are, a squirrel is not. [Note: Under the current HO policy exclusion, since a squirrel IS a rodent, that portion of the exclusion would preclude coverage. – Ed.]

Sincoff v Liberty Mut. Fire Ins. Co., 11 N.Y.2d 386, 183 N.E.2d 899, 230 N.Y.S.2d 13 (NY Court of Appeals, 1962):

This case involved damage caused by carpet beetles. The court held that because the parties’ experts disagreed over the meaning of the term vermin, and because the dictionaries had varying meanings, the term was capable of more than one meaning and the doubt was therefore resolved in favor of plaintiffs. One of the experts acknowledged that “vermin” is not a scientific term, but rather that it is a popular colloquial expression with loose and varied popular and dictionary definitions.

In this case, as it is in any case involving “all risk” coverage, the court put the burden of proof on the defendant to conclusively demonstrate that a carpet beetle was a vermin. The court said, “It was not sufficient for the defendant to demonstrate that a purchaser of the policy involved herein might have construed ‘vermin’ to include carpet beetles. Defendant, to derive any benefit from the exclusory clause, was obliged to show: (1) that it would be unreasonable for the average man reading the policy to conclude that nonparasitic carpet beetles were not vermin, and (2) that its own construction was the only one that fairly could be placed on the policy. This the defendant was unable to do.”

Umanoff v. Nationwide Mutual Fire Insurance, 110 Misc. 2d 474, 442 N.Y.S.2d 892 (NY Civil Court, 1981):

This case involved damage by raccoons where the court opined that, “A claim for damage to the structure of plaintiff’s home following an invasion of raccoons is not barred by the exclusionary clause of the insurance policy, which specifically omits coverage for ‘vermin’, but does not define the term; the term “vermin” is capable of more than one meaning and, since ambiguities are construed against the insurer, the burden was on the insurer to establish that the term not only was susceptible of being defined by the average man so as to include raccoons, but that such definition was the only one that could fairly be placed thereon; moreover, including domestic animals as one of the excluded perils implies that nondomestic animals such as raccoons are covered.”

Jones v. American Economy Insurance Co., 672 S.W.2d 879 (Texas Court of Appeals, 1984):

This case, like Mercer above, involved damage by squirrels and the court opined, “‘Vermin’ is not a particular class of animals, such as rodents, to which squirrels belong. It is apparent that the definition of ‘vermin’ is very broad, covering entities as diverse as insects, animals, and persons. The few cases we have found in other jurisdictions are divided on this question. We conclude that the term does not have a simple, plain, and generally accepted meaning and that it is susceptible of more than one reasonable interpretation; therefore, we hold that the term is ambiguous.”

Marks v. Trinity Universal Insurance Company and Hardy & Murray, Inc., 531 So. 2d 516 (Louisiana Court of Appeals, 1988):

This case, like Umanoff above, involved raccoons and the court cited the logic of Jones v. American Economy above to find that “vermin” was ambiguous.

Christ Episcopol Church of Bastrop, LA v. Church Insurance Company, 731 So. 2d 1071 (Louisiana Court of Appeals, 1999):

This is the one case we know of where the court upheld the “vermin” exclusion. The case involved damage to the church organ caused by mice and rats. In citing various dictionary definitions and other sources, the court concluded that, despite varying definitions of “vermin,” the common feature in each was that the term includes mice and rats. [Note: Again, this point is moot since the current ISO HO-3 policy expressly excludes rodents. – Ed.]

So, based on the above, in our opinion the insurer would be hard pressed to demonstrate, as required by them when denying a claim under an “all risk” policy, that the term “vermin” includes bats. I’ve personally been involved in claim denials based on the “vermin” exclusion that involved raccoons, skunks, turtles, and snakes. In each claim, after looking at the case law, the insurers reversed their denials and paid the claims.



We have been told that some courts (mostly lower level courts where decisions are usually not precedent setting nor governing as a matter of law) in a few states have found bats to be vermin because of the noxious fumes and residue from their urine and droppings.

So, there could be a case for an animal being a vermin in one circumstance and maybe not another, just as a normally harmless substance has been alleged to be a pollutant under certain circumstances. Bats are, for the most part, very beneficial creatures because they keep the mosquito (and other parasitic insect) populations down…one of those rascals can devour thousands of real vermin in a night! However, I wouldn’t think kindly to them living in my attic…at THAT point, there’s probably an equitable argument for it being a vermin, but the courts don’t seem to support that situational position, just as relatively few courts have upheld the pollution exclusion for “harmless” substances.

IF the homeowners exclusion was written more like the commercial lines exclusion without the use of the term “vermin” (e.g., “Nesting or infestation, or discharge or release of waste products or secretions, by insects, birds, rodents or other animals.” in the ISO CP 10 30), it would probably be more likely that a claim such as this could be reliably denied. The more specific exclusion is probably more enforceable. I’ve gotten a couple of skunk claims paid for agents (believe it or not, one adjuster cited the pollution exclusion as part of the denial!), but pointed out that there wouldn’t have been coverage under the CP form.


October 2002 Update:

A reader sent us another court case reference, though we do not have access to the actual transcript. According to him, in the case of Ben Har Holding Corp. v. Fox, 263 N.Y.S. 695 (1933), the court found that bedbugs, cockroaches, water bugs, and red ants, along with noxious little animals or insects, collectively, as squirrels, rats, mice, worms, flies, bugs, etc. were vermin. The subject of this case, crickets, were found not to be vermin.


2011 Update:

The 2011 ISO Homeowners filing that is effective in May 2011 in most states has now adopted the commercial lines exclusion and removed the specific exclusionary reference to “vermin.”


Copyright 2001-2011 by the Independent Insurance Agents of America. All rights reserved.

Reprinted with permission.

The following two tabs change content below.

Bill Wilson

Founder at
One of the premier insurance educators in America on form, coverage, and technical issues; Founder and director of the Big “I” Virtual University; Retired Assoc. VP of Education and Research from Independent Insurance Agents & Brokers of America. Reprint Request Information