Managing Mole Problems

Moles are remarkable animals known for how they are specialized for life underground. They are seldom seen by humans and are often mistaken for pocket gophers, mice or shrews. In fact, the mole is not closely related to any small mammal except the shrew, both belonging to the mammalian order Insectivora. Moles often come into conflict with homeowners when they burrow in yards.

Identification
Moles are not rodents and do not have characteristic rodent features like large, sharp front teeth. Rather, they have sharp, pointed teeth (like a cat) used for catching and eating grubs and earthworms.

The mole's most remarkable features are its adaptations for life underground. It has greatly enlarged "paddle like" front feet and enlarged toenails uniquely adapted for digging. Male fur is short, soft and velvety and when brushed, offers no resistance in either direction. These two adaptations let moles literally "swim" forward and backward through the soil.

Other adaptations for this life include a cylindrical-shaped body; a long, tapered snout; and eyes so tiny they almost appear to be missing. The hind legs are very small enabling the mole to turn with ease in a narrow passage. Fully grown moles measure 4 to 7-1/2 inches long complete with a very short tail. Fur color varies from black, to brownish, to grayish with silver highlights.

Mole Facts and Biology
The two species commonly encountered in New York State are the eastern mole (Scalopus aquaticus) and the star-nosed mole (Condylura cristata). The star-nosed mole has 22 pink finger-like projections around its nose, which readily; distinguishes it from the eastern mole, whose nose is pointed and lacks the numerous projections. Moles can be found in a variety of habitats dominated by loose, well-drained soil. Moles are found in suburban lawns, cemeteries, golf courses, pastures, meadows, woodlands, sandy soils near streams, and light, loamy soils. Since they are adapted for life underground, they construct extensive underground tunnels, using two types: shallow surface ones in the spring, summer and fall and deep permanent ones used year around as the main avenues of travel. Nest cavities and "home" areas, six inches in diameter and lined with vegetation, can be found 12 to 18 inches beneath the soil surface and connect deep tunnels.

Moles are antisocial, solitary animals (they live alone except to breed). Males and females only come together for a brief encounter during February to mate. In April, after a 45-day gestation period, two to five large, hairless, helpless young are born in the underground nest chamber. They are about half grown at five weeks and leave the nest the next week to fend for themselves. They become sexually mature in one year.

Researchers at the University of Kentucky studied me eastern mole and found they are active any time of the day, but are most active from 4 to 7 AM and 6 to 9 PM, all year. Moles must be very active to meet high energy requirements. In fact, they can burrow as fast as one foot/minute. High energy mole food comes as grubs, earthworms, beetles, beetle larvae, insects and insect larvae, snails and spiders. Moles eat small amounts of plants parts only occasionally. Their appetite is almost insatiable and captive moles eat constantly as long as food to put in the cage. If captive moles do not get suitable nourishment, they die within several hours. Thus, one mole can be responsible for considerable damage to a lawn or garden.

A mole typically travels one-fifth acre. No more than three to five moles live on each acre and two to three is a more common number. Thus one mole will usually use more than one person's yard and, for effective control, several neighbors may need to cooperate.

Moles live for three to four years in the wild. Predators like fox, skunk, owl and even dogs and cats kill and eat moles. One method of control may be to get a good dog.

Burrowing and Tunnels
As mentioned previously, moles create shallow and deep tunnels. The mole is the only animal which will create a surface tunnel. These tunnels are usually temporary feeding burrows. Some may be used as travel lanes while others may be traveled infrequently or abandoned immediately after being dug. Surface tunnels are most abundant after a warm rain or during the spring and fall when moles are actively searching for insects or earthworms. Underground tunnels are often very deep and the only evidence that they exist may be mounds of soil (molehills) pushed up to the surface. They are used as highways leading from cavities to feeding areas and are used most during hot, dry or very cold weather when earthworms and insects move deeper into the soil.

Controlling Mole Damage
The first step in controlling moles is to actually determine if the mole is the culprit. Because moles are insectivores, they do not routinely eat garden seeds and bulbs, although they are often blamed. The real culprits are probably voles, white-footed mice or house mice. If your garden has runways in it, the moles are looking for insects and earthworms.

Moles play a beneficial role in the management of soil and control of undesirable grubs and insects. Moles are one of nature's small mammals that have worked for a long time in moving soil around. By tunneling and shifting soil particles, moles permit better aeration of the soil and allow humus (organic matter) to travel deeper into the soil This tunneling also allows subsoil material to be moved closer to the surface where nutrients may be more available to plant roots.

Perhaps the mole's greatest crime is the nuisance it creates in lawns or gardens. If you have this problem, then take control measures.

Trapping
The most effective way to control males is trapping. Why is trapping so effective and why is it the recommended control option? The answer lies in the mole's unique biological attributes.

As mentioned previously, moles are solitary and have a high energy requirement which dictates a large feeding territory. Thus mole densities are not as great as you might imagine. A single lawn may have only one or two moles which means the offending animals can be removed and the problem solved. In addition, mole reproduction is so low that areas are not repopulated quickly.

The habit of moles to quickly open and repair damaged runways provides another advantage in trapping. A mole becomes suspicious when it encounters anything unusual in its burrow (steel leg hold traps), but is not suspicious of soil blocking the runway. When it encounters a blockage, the mole immediately pushes its way into the blocked area, reopens it and continues on its merry way. Specially designed mole naps take advantage of this habit and moles do not suspect a trap is hidden there.

When preparing to trap moles, be aware that moles are sensitive to anything unnatural in their environment. Be careful not to tear up large amounts of soil or many sections of burrows when setting a trap. Also be aware that a poorly set or incorrectly placed trap is an immediate danger signal to the mole and will act as a detour for every mole. Trapping moles takes patience and persistence. If you have an on-going problem, you may need to set traps during most of the summer.

Types of Mole Traps
Three types of mole traps are currently available and all work equally well if used properly (Figures 1 and 2). The brand names of these traps are Victor Harpoon Trap® Out O'Sight Scissor-jaw Trap® and Nash Choker-loop Trap®. The harpoon trap has sharp spikes which spear the mole as it passes. The scissor-jaw trap kills by grabbing the animal, while the choker-type trap has a loop that tightens around the mole's body. You can buy traps at local hardware, ag supply, or feed and seed stores or from the following manufacturers:

When and Where to Trap
Trap site selection and timing are critically important if trapping is to be successful. Because of the difficulty in placing a trap in a deep burrow, most trapping is done on surface burrows. Remember surface runways are used most actively during the spring and fall and immediately after a warm rain. So, trap during these periods because the likelihood of catching the animal is increased.

To be successful, you must also find an active burrow. Active burrows are relatively straight runways that may connect two systems of foraging activity. A burrow system that ends abruptly has probably bean abandoned and a burrow system that is highly branched, tunneling back on itself is probably a foraging burrow and may be abandoned. In addition, burrows that have numerous mouse holes or breaks are probably not being used. To find a frequently used burrow, tramp down with your foot on each runway. Within 12 to 24 hours active runways will be repaired. Then you can put a trap in this location. If the trap has not captured a mole in three days (1) the trap was placed in the wrong location, (2) the runway was disturbed too much, (3) the trap was improperly set and the mole detected it, (4) the mole changed its habits and was not actively using the burrow, or (5) you captured all the moles in the general area.

Traps are generally more effective if set in the late afternoon or early evening (4 to 6 PM) coinciding with the activity period mentioned earlier. Be sure to check the spring mechanism several times to ensure the trap is working adequately prior to placement in the burrow system. If traps need m be relocated wait until after the morning activity period. Be sure to handle the traps safely, keep them away from children, and follow the manufacturer's directions. Put a small bucket over them if children or pets are present.

The following instructions show the proper use of each type of trap.

Setting a Harpoon-Type Level and lightly pack down the runway ridge with your foot. Set the trap (with the safety catch in place) so that it straddles the active runway and is inserted deeply enough to prevent recoil when the trap is sprung (Figure 3); The trigger pan should touch the flattened ridge. Release the safety catch allowing the spikes to be forced into the runway (or raise and release the spikes several times to make holes in the soil for the spikes to enter). Set the trap and leave it alone. Do not disturb any other part of the mole's runway system.

Setting the Scissor-Jaw Trap Dig out a section of a straight runway with a garden trowel across the runway a little deeper than the burrow and as wide as the trap, Figure 4 (a). Note the exact direction of the tunnel indicated by the open ends. Replace and repack the loose soil as shown in Figure 4 (b). Set the trap (be sure to secure the safety catch). Place the trap in the runway so that it straddles the open runway, Figure 4 (c). Be sure the trigger mechanism touches the packed soil between the jaws. Place the trap so that the ends of the jaws are set about one inch below the runway so the mole has to pass between the jaws. Set the trigger mechanism so that it will spring easily. Release the safety catch and be extremely careful when handling these traps. Control Recommendations Not Recommended No known "short cuts" or "magic potions" are useful in controlling moles. One of the most common of these surefire remedies has been to place chewing gum in the burrow. Research has shown that doing so has no effect on moles even if they eat it. Do not place broken glass, razor blades, rose branches, bleaches, diesel fuel, lye, sheep dip, or human hair down the burrow system to drive the mole away. Do not use poison peanuts. Remember, moles eat insects and earthworms, not nuts. Poisons are also a danger to family pets or other wildlife.

The use of insecticides to destroy the mole's food source is also not recommended. If you have a grub problem, contact Cornell Cooperative Extension of Suffolk County for information on treating the problem. Therefore, treat your lawn for a grub problem, not a mole problem.

Some people think that the mole plant, Euphorbia lathyris, or castor bean plants repel moles. However, these plants' repellent properties are doubtful. In addition, they are poisonous to humans. Also, because they easily escape cultivation they may become a problem weed

For More Information
The Mammals of Kentucky. R.W. Barbour and W.H. Davis. 1974. The University of Kentucky Press, Lexington.

Home Range, Movements, and Diet Activity of the Eastern Mole, Scalopus aquaticus. M.J. Harvey. 1967. Ph.D. Thesis, University of Kentucky, Lexington. This very technical research article contains superb information on moles in central Kentucky.

"Moles." F.R. Henderson. 1984. in Prevention and Control of Wildlife Damage (R.M. Timm, editor). Great Plains Agricultural Council and Nebraska Cooperative Extension Service, University of Nebraska, Lincoln.

Information obtained from: Managing Mole Problems in Kentucky, University of Kentucky - Cooperative Extension Service, by Thomas G. Barnes, FOR-42, issued
10-89.

For more information contact: Tom Kowalsick, Extension Educator - Horticulture, CCE - Suffolk County

Horticulture Leaflets Online

4/03