House mice are gray or brown rodents with relatively large ears and small eyes. An adult weighs about 1/2 ounce and is about 5 1/2 to 7 1/2 inches long, including the 3 to 4 inch tail. Although house mice usually feed on cereal grains, they will eat many kinds of food. They eat often, nibbling bits of food here and there. Mice have keen senses of taste, hearing, smell and touch. They are excellent climbers and can run up any rough vertical surface. They will run horizontally along wire cables or ropes and can jump up 13 inches from the floor onto a flat surface. They can slip through a crack that a pencil will fit into slightly larger than 1/4 inch in diameter. In a single year, a female may have five to 10 litters of usually five or six young each. Young are born 19 to 21 days after mating, and they are mature in six to 10 weeks. The life span of a mouse is about nine to 12 months. 

Damage

House Mice are carriers of Salmonella. Salmonella can be transferred in food preparation and food storage areas. Salmonella lives in the intestinal tracts of humans and other animals, including birds. Salmonella is usually transmitted to humans by eating foods contaminated with animal feces. House Mice are also due to their gnawing of electrical wires & such. 

Deer mice are named so because of their color pattern resembling that of a deer. They have a brown body with a white underbelly and feet. They also are very fast runners and agile jumpers which gives them very “deer” like characteristics. Deer mice range in length from 5-8 inches including the tail. They have large dark eyes, ears, and a bi-colored tail.

 Only some kinds of mice and rats can give people hantaviruses that can cause HPS. In North America, they are the deer mouse, the white-footed mouse, the rice rat, and the cotton rat. However, not every deer mouse, white-footed mouse, rice rat, or cotton rat carries a hantavirus. Other rodents, such as house mice, roof rats ,and Norway rats, have never been known to give people HPS. Since it is hard to tell if a mouse or a rat carries a hantavirus, it is best to avoid all wild mice and rats and to safely clean up any rodent urine, droppings, or nests in your home. Dogs and cats cannot give people hantavirus infections.

There are 22 species of Wood rats more often called Packrats or Trading Rats, in North and Central America. They are found from deserts and forests to high, rocky mountainsides. There are 7 species Wood rats of the North American deserts. Wood rats are pale buff, gray or reddish brown, usually with white undersides and feet. They have relatively large ears and, normally, hairy tails. They range in length from 8 to 20 inches, including their 3- to 9-inch tail.

Wood rats can cause extensive damage to your property. Not only do Wood Rats damage and destroy landscaping, they can also chew through wiring and spoil food. Wood rats may also shred upholstered furniture and mattresses for lining nests. Pack rats seek opportunities to nest in cars, A/C units and pool equipment and will chew through wiring creating thousands of dollars of damage. They may take up residence in parked vehicles, gnawing on wires and other mechanical components.

The roof rat is dark brown to black in color and measures 13 to 18 inches in length including tail. They weigh 5-9 ounces, are slender, and their ears are large and nearly hairless. Their droppings are long and cylindrical.

Rats can spread disease. Sometimes they transmit disease directly by contaminating food with their urine or feces or by biting people. Indirectly, they transmit by infecting as when fleas bite a disease-infected rat, then a person or other animal. Rat burrows can cause structural damage by undermining the foundations of buildings, roads and walkways, can cause damage by gnawing, damaging plastic and lead pipes, door frames, upholstery, and electric wires, and can cause damage through the destruction and contamination of stored foods.

The Norway rat is a stocky burrowing rodent, unintentionally introduced into North America by settlers who arrived on ships from Europe. Also called the brown rat, house rat, barn rat, sewer rat, gray rat, or wharf rat, it is a slightly larger animal than the roof rat.  Adult Norway rats weigh an average of 1 pound. Their fur is coarse and usually brownish or reddish gray above and whitish gray on the belly. Blackish individuals occur in some locations.

Damage

 Norway rats consume and contaminate foodstuffs and animal feed. They may damage crops in fields prior to and during harvest, and during processing and storage. Rats also damage containers and packaging materials in which foods and feed are stored. Rats cause structural damage to buildings by burrowing and gnawing. They undermine building foundations and slabs, cause settling in roads and railroad track beds, and damage the banks of irrigation canals and levees. Rats also may gnaw on electrical wires or water pipes, either in structures or below ground. They damage structures further by gnawing openings through doors, window sills, walls, ceilings, and floors. Considerable damage to insulated structures can occur as a result of rat burrowing and nesting in walls and attics. Among the diseases rats may transmit to humans or livestock are murine typhus, leptospirosis, trichinosis, salmonellosis (food poisoning), and ratbite fever. Plague is a disease that can be carried by a variety of rodents, but it is more commonly associated with roof rats than with Norway rats.

It is easy to identify ground squirrels, since they forage aboveground near their burrows. Their body measures 9 to 11 inches, while their semi-bushy tail adds another 5 to 9 inches in length. Their fur is brownish gray and speckled with off white along the back; the sides of the head and shoulders are light gray to whitish. One subspecies that inhabits most of Northern California has a dark, triangular-shaped patch on its back between the shoulders; this patch is missing from other species.

Damage

Ground squirrels damage many food-bearing and ornamental plants. Particularly vulnerable are grains as well as nut and fruit trees such as almond, apple, apricot, orange, peach, pistachio, prune, and walnut. Ground squirrels will enter gardens and devour vegetables in the seedling stage. They can damage young shrubs, vines, and trees by gnawing bark, girdling trunks (the process of completely removing a strip of bark from a tree's outer circumference), eating twigs and leaves, and burrowing around roots. Ground squirrels will gnaw on plastic sprinkler heads and irrigation lines. They also eat the eggs of ground-nesting birds and can limit attempts to attract quail to the yard.

Gophers have small external ears and small eyes. As sight and sound are severely limited, gophers are highly dependent on the sense of touch. The vibrissae (whiskers) on their face are very sensitive to touch and assist pocket gophers while traveling about in their dark tunnels. The tail is sparsely haired and also serves as a sensory mechanism guiding gophers’ backward movements. The tail is also important in thermoregulation, acting as a radiator. Pocket gophers are medium-sized rodents ranging from about 5 to nearly 14 inches long. Adult males are larger than adult females. Their fur is very fine, soft, and highly variable in color. Colors range from nearly black, to pale brown, to almost white. The great variability in size and color of pocket gophers is attributed to their low dispersal rate and thus limited gene flow, resulting in adaptation to local conditions.

Damage

It is relatively easy to determine the value of the forage lost to pocket gophers. Pocket gophers at a density of 32 per acre decreased the forage yield by 25% on foothill rangelands in California, where the plants were nearly all annuals. Plains pocket gophers reduced forage yield on rangelands in western Nebraska by 21% to 49% on different range sites. Alfalfa yields in eastern Nebraska were reduced as much as 46% in dry land and 35% in irrigated alfalfa. Losses of 30% have been reported for hay meadows.