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The 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 gopher" on its own may be used to refer to any of a number of subspecies of the family.

Distribution

Pocket gophers are widely distributed in North America, extending into Central America.

Appearance

Gophers are heavily built, and most are 12 to 30 cm (4.7 to 12 in) long, weighing a few hundred grams. A few species reach weights approaching 1 kg (2.2 lb). Within any species, the males are larger than the females and can be nearly double their weight.^[1] Most gophers have brown fur that often closely matches the color of the soil in which they live. Their most characteristic features are 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.

Behavior

All pocket gophers are burrowers. They are larder 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 20 cm (7.9 in) in diameter. These mounds will often appear in vegetable gardens, lawns, or farms, as gophers like moist soil (see Soil biomantle). They also enjoy feeding on vegetables. For this reason, some species are considered agricultural pests. They may also damage trees in forests. Although they 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.

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.^[2]

Classification

There has been much debate among taxonomists about which races of pocket gopher should be recognised as full species, and the following list cannot be regarded as definitive.

• Family Geomyidae
  • Genus Cratogeomys; some authors treat this genus as a subgenus of Pappogeomys.
    • Yellow-faced Pocket Gopher (Cratogeomys castanops)
    • Oriental Basin Pocket Gopher (C. fulvescens)
    • Smoky Pocket Gopher (C. fumosus)
    • Llano Pocket Gopher (C. gymnurus)
    • Merriam´s Pocket Gopher (C. merriami)
  • Genus Geomys - eastern pocket gophers; principally found in the south-western United States, east of the Sierra Nevada mountains.
    • Geomys arenarius; two subspecies, the Desert and White Sands Pocket Gophers
    • Attwater's Pocket Gopher (G. attwateri)
    • Plains Pocket Gopher (G. bursarius); two subspecies
    • Jones' Pocket Gopher (G. knoxjonesi)
    • Geomys personatus; 5 subspecies including the Texas, Davis, Maritime and Carrizo Springs Pocket Gophers
    • Geomys pinetis; 4 subspecies, the Southeastern, Cumberland Island, Sherman's and Goff's Pocket Gophers
    • Geomys texensis; 2 subspecies, including the LLano Pocket Gopher
  • Genus Orthogeomys - giant pocket gophers or taltuzas; found in Mexico, Central America and Colombia.
    • Chiriqui Pocket Gopher (Orthogeomys cavator)
    • Cherrie´s Pocket Gopher (O. cherriei)
    • Oaxacan Pocket Gopher (O. cuniculus)
    • Darien Pocket Gopher (O. dariensis)
    • Giant Pocket Gopher (O. grandis)
    • Variable Pocket Gopher (O. heterodus)
    • Hispid Pocket Gopher (O. hispidus)
    • Big Pocket Gopher (O. lanius)
    • Nicaraguan Pocket Gopher (O. matagalpae)
    • Thaeler´s Pocket Gopher (O. thaeleri)
    • Underwood´s Pocket Gopher (O. underwoodi)
  • Genus Pappogeomys; found in Mexico.
    • Alcorn´s Pocket Gopher (Pappogeomys alcorni)
    • Buller´s Pocket Gopher (P. bulleri)
  • Genus Thomomys - western pocket gophers; widely distributed in North America, extending into the northwestern US, Canada and the southeastern US.
    • Thomomys bottae; many subspecies, including the Botta's, Fish Spring, Bonneville, Clear Lake, San Antonio, Pistol River, Mount Ellen, Guadalupe, Limpia, Mearns', Stansbury Island, Antelope Island, Cebolleta, Salinas, Skull Valley, Swasey Springs, Harquahala and Limpia Greek Pocket Gophers.
    • Camas Pocket Gopher (T. bulbivorus)
    • Wyoming Pocket Gopher (T. clusius)
    • Idaho Pocket Gopher (T. idahoensis)
    • Mazama Pocket Gopher (T. mazama); several subspecies including the Western, Gold Beach, Olympic, and Tacoma Pocket Gophers.
    • Mountain Pocket Gopher (T. monticola)
    • Northern Pocket Gopher (T. talpoides); very widely distributed; several subspecies including the Cheyenne Northern Pocket Gopher
    • Townsend´s Pocket Gopher (T. townsendii)
    • Southern Pocket Gopher (T. umbrinus)
  • Genus Zygogeomys
    • Michoacan Pocket Gopher or Tuza (Zygogeomys trichopus)

Some sources also list a genus Hypogeomys, with one species, but this genus name is normally used for the Malagasy Giant Rat, which belongs to the family Nesomyidae.

Control

Geomys spp and Thomomys spp are classed as "prohibited new organisms" under New Zealand's Hazardous Substances and New Organisms Act 1996 preventing it from being imported into the country.^[3]

References