Pocket gophers are burrowing rodents of the family Geomyidae. These are the “true” gophers, though several ground squirrels of the family Sciuridae are often called gophers as well. The name pocket gopheron its own may be used to refer to any of a number of subspecies of the family. Pocket gophers are a symbol of the state of Minnesota, sometimes called the Gopher State.
Gophers are heavily built, and most are moderately large, ranging from 4.7 to 12 inches in length, and weighing a few hundred grams. A few species reach weights approaching 2.2 lb. Males are always larger than the females and can be nearly double their weight. Most gophers have brown fur which often closely matches the color of the soil in which they live. Their most characteristic feature is their large cheek pouches, from which the word pocket in their name derives. These pouches are fur-lined, and can be turned inside out. They extend from the side of the mouth well back onto the shoulders. They have small eyes and a short, hairy tail which they use to feel around tunnels when they walk backwards.
Pocket gophers are solitary outside of the breeding season, aggressively maintaining territories that vary in size depending on the resources available. Males and females may share some burrows and nesting chambers if their territories border each other, but in general, each pocket gopher inhabits its own individual tunnel system.
Depending on the species and local conditions, pocket gophers may have a specific annual breeding season, or may breed repeatedly through the year. Each litter typically consists of two to five young, although this may be much higher in some species. The young are born blind and helpless, and are weaned at around forty days.
All pocket gophers are burrowers. They are hoarders and their cheek pouches are used for transporting food back to their burrows. Gophers can collect large hoards. Their presence is unambiguously announced by the appearance of mounds of fresh dirt about 8 inches in diameter. These mounds will often appear in vegetable gardens, lawns, or farms, as gophers like moist soil. They also enjoy feeding on vegetables. They may also damage trees in forests.
For this reason, some species are considered agricultural pests. There have been many ways devised to exterminate them, and several commercial enterprises have capitalized on methods using ultrasonic units embedded in the ground, poison baits and traps. These methods, however, are largely ineffective since new pocket gophers will return to existing tunnels and easily reinhabit an area.
Carbon monoxide from vehicle exhaust is an effective and inexpensive method that some people use to exterminate gophers. However, poisoning animals with carbon monoxide is illegal in some states, including California. Garden hoses are coupled to the exhaust pipes of vehicles using medium size soda bottles and duct tape, and with one end of the hose connected to the exhaust and the other end in the gopher tunnel, a vehicle is idled until toxic carbon monoxide fills the tunnel network, killing the gophers. This usually takes about 30 minutes.
A concussion method kills gophers instantly with a shock wave. Specialized equipment used by trained operators wearing personal protective equipment injects a mixture of propane and oxygen into the gopher burrow. An igniter on the end of the injection probe explodes the fuel mixture, destroying not only the gophers, but the burrows as well. It sends a fireball and intense shock wave throughout the tunnel network. This method is obviously not suited for urban residential areas. The destruction of the burrows by this method prevents loss of irrigation water, prevents injury from collapse of the burrow underfoot, and may make any reinfestation more quickly noticeable. Killing animals with explosives is illegal in some jurisdictions, although the concussion method is not regulated by US federal law. In Colorado the concussion method was approved for the control of prairie dogs in November of 2007.
Although pocket gophers will attempt to flee when threatened, they may attack other animals, including cats and humans, and can inflict serious bites with their long, sharp teeth.