Thomomys bottae Eydoux & P. Gervais 1836
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Geomyidae
Thomomys
Thomomys bottae

description: 12.
Botta’s Pocket Gopher
Thomomys bottae
French: Gaufre de Botta / German: Gebirgstaschenratte / Spanish: Tuza de Botta
Other common names: Valley Pocket Gopher
Taxonomy. Oryctomys (Saccophorus) bottae Eydoux & P. Gervais, 1836,
“coast of California.” Restricted by S. F. Baird in 1855 to “Monterey and San Francisco” (Monterey Co., California, USA).
Placed into subgenus Megascapheus. Nearly 200 subspecies were formerly recognized in the literature. One hundred thirtythree subspecies recognized.
Subspecies and Distribution.
T.b.bottaeEydoux&Gervais,1836—PacificcoastofC&SCalifornia,USA.
T.b.abbottiHuey,1928—PacificcoastofCBajaCalifornia,Mexico.T°b.abstrususHall&Davis,1935—NyeCounty,Nevada,USA.
T.b.actuosusKelson,1951—CNewMexico,USA.
T.b.albatusGrinnell,1912—SCCalifornia,USA.
T.b.albicaudatusHall,1930—NUtah,USA.
T.b.alexandraeGoldman,1933—NCArizona,USA.
T.b.alpinusMerriam,1897—SierraNevadaRangeofCCalifornia,USA.
T.b.alticolusJ.A.Allen,1899—SBajaCaliforniaSur,Mexico.
T.b.analogusGoldman,1938—SECoahuila,Mexico.
T.b.angustidensBaker,1953—NWCoahuila,Mexico.
T.b.anitaeJ.A.Allen,1898—SBajaCaliforniaSur,Mexico.
T.b.aphrastusElliot,1903—NWBajaCalifornia,Mexico.
T.b.aurerventrisHall,1930—NWUtah,USA.
T.b.aureusJ.A.Allen,1893—NEArizonaandadjacentpartsofUtah,Colorado,andNewMexico,USA.
T.b.awahneeMerriam,1908—WCCalifornia,USA.
T.b.baileyiMerriam,1901—NWTexas,USA.
T.b.basilicaeBenson&Tillotson,1940—NWSonora,Mexico.
T.b.birdseye:Goldman,1937—SWUtah,USA.
T.b.bonneuvilletDurrant,1946—WCUtah,USA.
T.b.borjasensisHuey,1945—SBajaCalifornia,Mexico.
T.b.brazierhowelliHuey,1960—WCBajaCalifornia,Mexico.
T.b.brevidensHall,1932—CNevada,USA.
T:b.cactophilusHuey,1929—SBajaCalifornia,USA.
T.b.camoaeBurt,1937—PacificcoastofSSonora,Mexico.
T.b.canusBailey,1910—NWNevada,USA.
T.b.catalinaeGoldman,1931—SCArizona,USA.
T.b.catavinensisHuey,1931—SEBajaCalifornia,USA.
T.b.centralisHall,1930—SEUtah,USA.
T.b.cervinusJ.A.Allen,1895—SWArizona,USA.
T:b.chrysonotusGrinnell,1912—SWArizona,USA.
T.b.cinereusHall,1932—WCNevada,USA.
T:b.collisHooper,1940—WCNewMexico,USA.
T.b.concisorHall&Davis,1935—CNevada,USA.
T.b.confinalisGoldman,1936—SWTexas,USA.
T.b.connectensHall,1936—NCNewMexico,USA.
T.b.contractusDurrant,1946—SWUtah,USA.
T.b.convergensNelson&Goldman,1934—WCSonora,Mexico.
T.b.convexusDurrant,1939—WCUtah,USA.
T:b.cultellusKelson,1951—NENewMexicoandSEColorado,USA.
T.b.cuniculariusHuey,1945—NCBajaCalifornia,Mexico.
T.b.curtatusHall,1932—WCNevada,USA.
T.b.depressusHall,1932—WCNevada,USA.
T.b.desertorumMerriam,1901—NWArizona,USA.
T.b.detumidusGrinnell,1935—SWOregon,USA.
T.b.dissimilisGoldman,1931—SEUtah,USA.
T.b.divergensNelson&Goldman,1934—NESonora,Mexico.
T:b.estanciaeBenson&Tillotson,1939—NESonora,Mexico.
T.b.fulvusWoodhouse,1852—NCArizonatoSWNewMexico,USA.
T.b.fumosusHall,1932—CNevada,USA.
T.b.guadalupensisGoldman,1936—WCTexas,USA.
T:b.homorusHuey,1949—NBajaCaliforniaSurintoSBajaCalifornia,Mexico.
T.b.howelliGoldman,1936—ECUtahintoWCColorado,USA.
T.b.humilisBaker,1953—NCoahuila,Mexico.
T:b.imitabilisGoldman,1939—SBajaCaliforniaSur,Mexico.
T.b.incomptusGoldman,1939—-WCBajaCaliforniaSur,Mexico.
T:b.internatusGoldman,1936—SCColorado,USA.
T.b.jojobaeHuey,1945—NCBajaCalifornia,Mexico.
T.b.juarezensisHuey,1945—NCBajaCalifornia,Mexico.
T.b.lachuguillaBailey,1902—WCTexas,USA.
T.b.lacrymalisHall,1932—WCNevada,USA.
T:b.laticepsBaird,1855—NWCaliforniaintoSWOregon,USA.
T.b.latusHall&Davis,1935—WCNevada,USA.
T.b.lenisGoldman,1942—CUtah,USA.
T.b.leucodonMerriam,1897—NCaliforniaintoSWOregon,USA.
T:b.levidensisGoldman,1942—CUtah,USA.
T.b.limitarisGoldman,1936—SWTexas,USA.
T.b.limpiaeBlair,1939—SWTexas,USA.
T.b.litorisBurt,1940—WCBajaCaliforniaSur,Mexico.
T.b.lucidusHall,1932—NCBajaCalifornia,Mexico.
T.b.lucrificusHall&Durham,1938—CNevada,USA.
T.b.magdalenaeNelson&Goldman,1909-WCBajaCaliforniaSur,Mexico.
T.b.martirensisJ.A.Allen,1898—NCBajaCalifornia,Mexico.
T.b.mearnsiBailey,1914—SWNewMexico,USA.
T.b.mewaMerriam,1908—CCalifornia,USA.
T:b.minimusDurrant,1939—NWUtah,USA.
T.b.modicusGoldman,1931—SCArizona,USA,intoNCSonora,Mexico.
T.b.morulusHooper,1940—NCNewMexico,USA.
T.b.nanusHall,1932—SCNevada,USA.
T.b.navusMerriam,1901—NCCalifornia,USA.
T.b.neglectusBailey,1914—SWCalifornia,USA.
T.b.nesophilusDurrant,1936—NWUtah,USA.
T.b.nigricansRhoads,1895—SWCalifornia,USA,intoNWBajaCalifornia,Mexico.
T.b.operariusMerriam,1897—SECalifornia,USA.
T.b.optabilisGoodman,1936—SWColorado,USA.
T.b.opulentusGoldman,1935—C&SCNewMexico,USA.
T:b.osgoodiGoldman,1931—SCUtah,USA.
T.b.paguataeHooper,1940—NWNewMexico,USA.
T:b.pascalisMerriam,1901—CCalifornia,USA.
T:b.pectoralisGoldman,1936—SENewMexico,USA.
T.b.peramplusGoldman,1931—NEArizonaintoNWNewMexico,USA.
T.b.perditusMerriam,1901—CCoahuilaintoNWNuevoLe6n,Mexico.
T.b.perpallidusMerriam,1886—SCCalifornia,USA.
T:b.pervagusMerriam,1901—NCNewMexicointoSCColorado,USA.
T.b.pervariusGoldman,1938—SWTexas,USA.
T:b.phelleoecusBurt,1933—SCNevada,USA.
T.b.pinalensisGoldman,1938—SCArizona,USA.
T:b.planirostrisBurt,1931—SWUtahintoNWArizona,USA.
T.b.planorumHooper,1940—WCNewMexico,USA.
T.b.powellDurrant,1955—SCUtah,USA.
T.b.proximarinusHuey,1945—NWBajaCalifornia,Mexico.
T:b.pusillusGoldman,1931—SCArizona,USA.
T.b.retractusBaker,1953—NCoahuila,Mexico.
T.b.rhizophagusHuey,1949—SWBajaCalifornia,Mexico.
T.b.ripariusGrinnell&Hill,1936—SECalifornia,USA.
T.b.robustusDurrant,1946—NWUtah,USA.
T.b.rubidusYoungman,1958—SCColorado,USA.
T.b.ruidosaeHall,1932—SCNewMexico,USA.
T.b.rupestrisChattin,1941—SCCalifornia,USA.
T.b.ruricolaHuey,1949—SWBajaCalifornia,USA.
T:b.russeolusNelson&Goldman,1909—SWBajaCaliforniatoNWBajaCaliforniaSur,Mexico.
T.b.saxatillisGrinnell,1934—NECalifornia,USA.
T.b.scotophilusDavis,1940—WCTexas,USA.
T.b.sevieriDurrant,1946—WCUtah,USA.
T.b.siccovallisHuey,1945—CBajaCalifornia,Mexico.
T:b.simulusNelson&Goldman,1934—SEIdaho,USA.
T:b.sinaloaeMerriam,1901—NWandWCSinaloa,Mexico.
T.b.solitariusGrinnell,1926—WCNevada,USA.
T:b.spatiosusGoldman,1938—SWTexas,USA.
T.b.stansburyDurrant,1946—NWUtah,USA.
T:b.sturgisiGoldman,1938—NWCoahuilaintoEChihuahua,Mexico.
T.b.subsimilisGoldman,1933—SWArizona,USA.
T.b.texensisBailey,1902—SWTexas,USA.
T.b.tiviusDurrant,1937—CUtah,USA.
T.b.toltecusJ.A.Allen,1893—SWNewMexico,USA,intoNWChihuahua,Mexico.
T.b.tularosaeHall,1932—SCNewMexico,USA.
T.b.vanrosseniHuey,1934—NWSonora,Mexico.
T.b.varusHall&Long,1960—WCSinaloa,Mexico.
T.b.vescusHall&Davis,1935—CNevada,USA.
T.b.villa:Baker,1953—NWCoahuila,Mexico.
T.b.wahwahensisDurrant,1937—WCUtah,USA.
T.b.winthropiNelson&Goldman,1934—WCSonora,Mexico.
T. b. xerophilus Huey, 1945 — NC Baja California, Mexico.
Descriptive notes. Head—body 90-200 mm (males) and 80-175 mm (females), tail 60— 95 mm (males) and 55-75 mm (females); weight 110-250 g (males) and 80-160 g (females). Botta’s Pocket Gopher has a very broad geographical distribution, encompassing the entire southern one-half of western USA into northern Mexico. Extreme variation in body size and pelage color throughoutits distribution explains the large number of described subspecies. Some authors believe that many, if not most, of these subspecies would not stand up to a detailed analysis of taxonomic status using modern systematic tools. Individuals living at higher elevations or in thinnersoils are usually much smaller than individuals living at lower elevations and in deeper soils. Males continue to grow with age, whereas growth in females ceases after they begin to reproduce. As a result, males of smaller subspecies are somewhat larger than females, but males of larger subspecies can be up to ¢.15% larger than females. Color of dorsal pelage can be black in melanistic populations, white in albinistic individuals, dark-to-light brown, reddish brown, yellowish brown, pale gray, yellowish gray, and all shades between these many colors. Some individuals have patches of white fur on throat, chest, or belly, and some populations show subtle changes in hair color seasonally. Botta’s Pocket Gopher has the fusiform body shape typical ofall pocket gophers, and it possesses furlined cheek pouches that open external to the mouth. Extensive cytogenetic studies of Botta’s Pocket Gopher byJ. L. Patton and his colleagues showed that most populations have a chromosomal complement of 2n = 76 and FN = 110-148. Populations extending from northeastern New Mexico into south-eastern Colorado show a cline in diploid number from 76 chromosomes in the south to 100 in the north. Additional chromosomes, above the typical diploid number of 76, are heterochromatic and potentially genetically inactive.
Habitat. Wide variety of habitats with many differentsoil types and depths from below sea level in Death Valley National Park, California, to above timberline in many mountain ranges in western USA. Botta’s Pocket Gophers are common in mountain meadows and tundra, sagebrush (Artemisia, Asteraceae) steppes, grasslands,forests, and suburban lawns and gardens. Similar to other pocket gophers, they appear to prefer deep soils in meadows and along rivers and streams, and they are common invadersof cultivated fields.
Food and Feeding. Diet of Botta’s Pocket Gopher consists of a wide variety of underground roots and tubers and a limited amount of surface vegetation. Nearly all species of plants in the vicinity of a burrow system are consumed, including annual and perennial monocots and dicots, perennial shrubs, cacti, and roots of a variety of tree species. Young shoots and entire seedlings of many plant species are pulled directly downward into a tunnel excavated beneath the plant. In many habitats, diet shifts seasonally, often in response to increased availabilities of forbs and grasses following spring rains. As in all other pocket gophers, the burrow system of Botta’s Pocket Gopher consists of a series of shallow feeding tunnels radiating spoke-like from a deeper, central network that contains one or more nest chambers and several smaller chambers for storage of food or fecal pellets. Many observations of aboveground foraging have been reported, almost always occurring within a few body lengths of a burrow entrance.
Breeding. Breeding season varies greatly across the distribution of Botta’s Pocket Gopher; low-elevation individuals breed in early spring and high-elevation individuals in late spring following snow melt. Most populations are thoughtto breed only once per year, but when breeding season is long (January-April in certain low-elevation habitats in California), females born early in the season will breed later in the same season. Males do not attain reproductive maturity until the year after their birth. Some populations of Botta’s Pocket Gophers may breed in spring and autumn in years when food is abundant. In most years, nearly all adult females breed, but relatively few adult males breed, suggesting that male competition for access to femalesis high. Sex ratio of adults in most populationsis heavily skewed in favor of females, and this is especially true in populations with extreme sexual size dimorphism. Litter sizes of Botta’s Pocket Gophers are 1-10 young, averaging 4-5 young/litter. Nutrition and food abundance affect litter size, and studies by J. L. Patton and his colleagues showed that femalesliving in alfalfa fields in the southern California desert had larger litters than those living in nearby desert scrub habitats. Gestation is 18-21 days, and young are weaned and expelled from burrows at ¢.35 days of age. Young disperse on the surface in search of suitable habitat not already occupied by a competitor.
Activity patterns. Botta’s Pocket Gopheris active at any hour of the day, with periods of peak activity around dawn and dusk. A study in southern California showed six individuals to be active an average of ¢.9 hours/day, with peak activity between 16:00 h and 20:00 h. Botta’s Pocket Gopher digs with its incisors and forelimbs, using hard enamel in the teeth to penetrate compact soils resistant to softer keratin in claws. In one study, growth rate of incisors averaged c.0-6 mm/day for the upper pair and almost 1 mm/day (36 cm/year) in the lower pair. Rate of claw growth varies widely butis usually slower than rate of incisor growth in species that dig with their teeth. Botta’s Pocket Gopher does not hibernate and is active year-round. Burrowing activity is low during hot, dry summers but increases dramatically with cooler temperatures and greater soil moisture in spring, autumn, and winter. Although most burrowing activity takes place in shallow feeding tunnels and is associated with foraging, individuals will also dig deep tunnels to avoid hot surface temperatures.
Movements, Home range and Social organization. A study of Botta’s Pocket Gophers living along the Rio Grande in New Mexico, USA, estimated average dispersal distances of ¢.400 m/year. Another study in California showed average daily movements of ¢.32 m for dispersing adult males, 28 m for adult females, and 21 m for subadult females. As in other pocket gophers, Botta’s Pocket Gopheris solitary and aggressively territorial. Because it rarely leaves its burrow system,its home range is defined by size and extent of its burrow system. Although they vigorously defend their burrow systems against intruders, captures of two or more individuals in the same system are not uncommon during the breeding season and when young are with their mothers. Male Botta’s Pocket Gophers tend to have larger burrow systems than females. Mean home range size was ¢.390 m? for females and ¢.810 m? for males in California. A similar study in New Mexico reported home range sizes of ¢.290 m?* for females and ¢.475 m® for males. Densities of ¢.75 ind/ha have been reported in natural habitats, and as many as 150 ind/ha have been recorded from agricultural lands (e.g. alfalfa fields).
Status and Conservation. Classified as Least Concern on The IUCN Red Last.
Bibliography. Baird (1855), Hafner et al. (1983), Howard & Childs (1959), Jones & Baxter (2004), Linzey, Timm, Alvarez-Castafieda & Lacher (2008b), Nadler etal. (1990), Patton (1999a, 2005b), Patton & Smith (1990), Vleck (1979).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Geomyidae, pp. 234-269 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 240-241, DOI: 10.5281/zenodo.6603807