Moles

Moles are creatures of darkness. They almost never leave their tunnels. Often falsely blamed for plant damage, moles are primarily insect eaters.

Closeup of a mole (Michael David Hill) CC BY-SA 3.0

Mole description

Moles are rather funny looking. They have stubby, hairless tails, cylindrical bodies (usually 5 to 7 inches long), pointed snouts, and short, webbed hands and feet. They don’t see very well because their eyes are covered with skin, and you can’t see their ears. Mole fur, however, is quite thick and velvety, and moleskin is the stuff of hiking blister legends. There are 42 mole species worldwide, 7 of which live in North America, and 4 species found in California:

• Shrew-mole (Neurotrichus gibbsii)
• Broad-footed mole (Scapanus latimanus)
  
• Alameda Island mole (S. latimanus parvus) - CDFW special concern; endemic
• Coast mole (S. orarius)
• Townsend's mole (S. townsendii)

Moles like their privacy. Unless it’s the breeding season, you will only find one mole per tunnel system. Moles have one litter each year, usually with 3 or 4 young, in spring.

​Differences between moles and pocket gophers

Many people assume that moles and voles (also known as pocket gophers) are related. They are not. Voles are plant eating rodents, while moles are primarily insect-eating members of the Scapanus species, more closely related to shrews. Crescent-shaped mounds with closed holes indicate the presence of pocket gophers.

​Pocket gopher populations can lead to girdled trees, slope erosion, and dead plants. Moles, on the other hand, have round mounds which may have open or closed holes, and long surface ridges from their shallow tunnels are often visible. Moles normally feed on worms, grubs, insects, and other invertebrates. Moles will occasionally eat mice, shrews, and nuts. Your average mole will eat 40 pounds of insects each year.

Shrew-mole (US NPS) Public Domain

Broad-footed mole (Sarah Murray) CC BY-SA 2.0

Mole tunnels

Moles create an extensive system of both deep and shallow tunnels. The deeper tunnels are their permanent housing, with separate rooms for food storage, sleeping, and rearing young. Tunnels are usually 2 inches in diameter and found 8 to 12 inches below the soil surface. The shallow tunnels are for hunting out grubs, worms, centipedes, and other soil dwelling creatures. It is the shallow tunnels that cause most of the problems associated with moles. As they burrow under the surface of the soil, looking for their supper, moles often dislodge smaller plants and expose root systems to the air, drying them out. If you want a lawn that looks like a putting green, moles are not your friends.

​Mole management

If you cannot tolerate moles in your garden or landscape, trapping will be necessary. While there are dozens of repellants, scaring devices, home remedies, and plants that claim to offend moles, research has not shown that any of these methods actually work. The only exception is castor oil solutions, which have been shown effective on eastern moles. Flooding tunnels wastes water and does not rid an area of moles. [They’ve dealt with floods for far longer than we have been gardening.]

Trapping always works. Underground harpoon traps and scissor-jaw traps are the most effective methods. Of course, this means dealing with a dead mole and a messy trap. Some new mole baits are showing limited effectiveness, but then you have to worry about children, pets, and local wildlife also suffering a horrible death. Plus, if your landscape was appealing to a mole before, it probably will be again, to a different mole. If you have valuable plants that need protection against moles, you can install a hardware cloth barrier 2-feet into the ground, with a 6-inch lip bent at a 90° angle away from the plant to thwart mole digging.

Mole trivia

Moles are fascinating creatures. Some of the more interesting mole facts include:

• A mole placed on the ground can burrow out of sight in 10 seconds.
• Moles have a special type of blood that allows them to breath in low oxygen environments.
• Moles have an extra thumb, called a prepollex.
• Female moles have a set of male genitals.
• Moles squeeze the dirt out of earthworms before eating them.
• Star-nosed moles can find, catch, and eat food faster than the human eye can see.
• Moles are the only animal known to smell things in stereo.

If you can tolerate moles, they actually provide many benefits to the garden and landscape.

Did you know that mole saliva contains toxins that paralyze earthworms? Researchers have found underground storage spaces filled with thousands of paralyzed earthworms, for later eating.

Now you know.