Rodentia Part I R.O.U.S.

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RodentiaPart IR.O.U.S.s

• Lab 3

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Order Rodentia

• Large chisel-like incisors
• No canines, forming a diastema between incisors
  and cheek teeth.
• Two main suborders
• Hystricognathi
• Sciurognathi
• We will cover the Hystricognathi and some of the
  larger Sciurognathi this week. Little
  Sciurognathians are to follow next week.

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Hystricognathi

• Enlarged infraorbital canal compared to
  Sciurognathi.
• Molariform teeth NOT 4 above and 4 below.
• Long gestation period and few young.
• Two North American Families
• Erethizontidae North American porcupine
• Myocastoridae - nutria

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Erethizon dorsatum

• North American porcupine
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat Deciduous, coniferous, and mixed
  forests in the northern parts of the united
  States into Canada
• Food strict vegetarian eating leaves, twigs,
  clover, and skunk cabbage in summer. In winter,
  it chews through the tough outer bark of trees
  like pine, fir, cedar, and hemlock to eat the
  inner cambium
• Reproduction mate October thru November, one
  young born in May-June after 7 month gestation.
  Young are precocial an with spines.
• Trivia Can girdle trees, causing serious
  economic damage. Also, defends itself by
  striking enemy with tail, not shooting any of its
  30,000 quills.

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Myocastor coypus

• Nutria
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat - live in freshwater and brackish marshes
  in many parts of the US and Canada, particularly
  in the south.
• Food Strict vegetarian eating aquatic
  vegetation like rushes, spike rush, pickeral
  week, cattail, and arrowhead.
• Reproduction Breed year round, gestating for
  130 days to produce 3-7 young. Can have up to
  three litters a year, although high miscarriages
  help to reduce this reproductive output.
• Trivia originally introduced as a fur crop in
  the early 1940s, this animal has become a pest
  species to commercial crops, particularly to
  sugarcane and rice fields, as well as damage to
  crawfish ponds from draining.

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Suborder Sciurognathi

• Castoridae
• Dipodidae
• Geomyidae
• Heteromyidae
• Muridae
• Sciuridae

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Family Sciuridae

• Ammospermophilus
• Cynomys
• Glaucomys
• Spermophilus
• Sciurus
• Tamias
• Tamiasciurus

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Cynomys ludovicianus

• Black-tailed Prairie Dog
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Make underground burrow systems in
  hardpan flats and the edges of shallow valleys
  from N. Mex and TP Texas N to North Dakota and
  Montana.
• Food Eat low growing weeds and grasses.
  Burrograss and purple needle grass are local
  favorites.
• Reproduction produce one litter of 4-5 young in
  March or April.
• Trivia Voracious eaters. Has been estimated
  that 256 eat as much as a cow. Currently
  declining in numbers due to varmint removal.

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Tamias (Eutamias) canipes

• Gray-footed chipmunk
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Downed logs along edges, mixed timber
  and brushy hillsides.
• Food Acorns, Douglas fir seeds, currants,
  gooseberries, mushrooms, green vegetation, and
  insects.
• Reproduction Mate within 10-20 after leaving
  hibernation, gestate for 31 days, and have one
  litter of 2-7 young. Rarely have 2nd litter.
• Trivia Found here in the Guadalupe Mountains
  National Park.

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Tamias striatus

• Eastern chipmunk
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat Open deciduous woodlands, forest edges,
  bushes and stone walls are common homes for this
  chipmunk found throughout most of the eastern
  United States
• Food nuts, seeds, slugs, snails, small inverts
  and vertebrates. Often attracted to feeders.
• Reproduction mate in early spring, gestate 31
  days, and have 1 litter of 3-5 young a year.
  Wean after a month, and begin to venture from the
  nest.
• Trivia Both species of chipmunk make large
  caches of food to hibernate with, as they do not
  put on fat like mainly other hibernating rodents.

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Ammospermophilus interpres

• Texas Antelope Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Found in desert regions of the SW,
  along edges of lower valleys and low hills.
  Commonly associated with creosote and juniper
  vegetation.
• Food eat variety of plants, including yucca,
  juniper, prickly pear, and cholla. Occasional
  insects
• Reproduction Breed in February, having one
  litter of 5-14 young. Some evidence of second
  litters in Texas.
• Trivia Active during the heat of the day. Will
  go to burrows and lie spread eagle on the bellies
  to cool down before darting out again..

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Spermophilus tridecemliniatus

• Thirteen-lined Ground Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Originally short grass prairies and
  dunelands, now found along roadsides, yards,
  cemeteries, and gold courses from Alberta south
  to Utah and Texas and east to Ohio.
• Food grass and forb seeds, caterpillars, and
  grasshoppers, will take birds, mice and shrews
• Reproduction Mates in April, gestate 27-28
  days, and have one litter of 8-10 young.
• Trivia These squirrels are actually solitary,
  only appearing in groups due to limitations of
  available habitat.

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Spermophilus spilosoma

• Spotted Ground Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Neb S thru W TX and into Central
  Mexico, W to Ariz. Dry sandy areas and disturbed
  habitats (roads, arroyos, and overgrazed areas.
• Food green veg (mesquite beans, sandbur,
  sunflower, iris), grasshoppers and beetles. Seen
  eating lizards and k-rats
• Reproduction Mate from Feb to July, gestate 30
  days, and have around 5-7 young. Two litters
  common.
• Trivia These squirrels are actually solitary,
  only appearing in groups due to limitations of
  available habitat.

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Spermophilus mexicanus

• Mexican Ground Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat West Texas S of the caprock and N Mex,
  Edwards plateau S into N Mexico.
• Food green veg (mesquite leaves and beans,
  agarita leaves, Shasta lily, Johnsongrass, pin
  clover, and grains. Also eat insects when
  available, and commonly take carrion.
• Reproduction Breed in March-Apr, gestate 30
  days, giving birth to 2-10 young.
• Trivia Will hibernate near Midland, but remain
  active year round farther south (Del Rio).

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Spermophilus variegatus

• Rock squirrel (paper)
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat semiarid cliffs, canyons, arroyos, and
  slopes throughout much of the desert southwestern
  United States and Mexico.
• Food nuts, seeds, grain, roots, berries,
  cactus, inverts, and fresh and dried meat.
• Reproduction Bred in March-April with an
  assumed month gestation, giving birth to 3-9
  young.
• Trivia These squirrels tend to be colonial with
  maternal groups. They have been studied by ISU
  affiliates such as W. Shriner (range and
  movement), and C. M. Ritzi D. W. Sparks
  (ectoparasites).

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Sciurus aberti

• Aberts squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Ponderosa pine forests in Colorado, New
  Mexico, Arizona, Mexico.
• Food ponderosa pine bark, seeds, buds, and
  flowers, as well as fungi, carrion, and antlers.
• Reproduction First litter born in April-May
  with 3-4 young after a gestation of 40 days.
  Generally have two or more litters per year.
• Trivia cool looking ear tufts, nuf said.

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Sciurus carolinensis

• Eastern Gray Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Mature high mast producing woodlands
  from the east coast of the US and Canada west to
  Saskatchewan and Texas
• Food Mast, bird nestlings, bark, fruits, buds.
• Reproduction Mates January-February, and in
  May-July, gestation 44 days, 2 Litters of 1-6
  young born in March, July, and August
• Trivia Zollner and Lima demonstrated that this
  and other sciurids scale, or differ, in their
  abilities to perceive cover at a distance. This
  scaling is also reflected in the ability of these
  squirrels to inhabit isolated woodlots

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Sciurus niger

• Fox Squirrel
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat More open woodlots, including small,
  isolated, and disturbed woodlots, occurring
  throughout much of the south and midwest.
• Food Mast, fruit, buds, flowers, bark, maple
  sap, and meat.
• Reproduction Mate December-January and
  May-June, gestate 45 days, have two litters of
  2-4 young each.
• Trivia Named after a melonistic specimen, these
  squirrels are considered to cohabitate well with
  humans. It is also a popular game animal.

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Tamiasciurus hudsonicus

• Red squirrel
• Dental formula 1/1 0/0 2-1/1 3/3 20-22
• Habitat originally evergreen forests, now in
  coniferous, hardwood, and mixed stands throughout
  the southwestern 2/3 of Canada and extending
  south along the Appalachians to Georgia.
• Food acorns, hickory nuts, beech nuts, hemlock
  cones, terminal buds and bark of conifers.
• Reproduction One or two litters per year of 3-7
  young after a 35 day gestation period.
• Trivia Form large middens or caches for the
  winter unlike most other scurids.

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Glaucomys volans

• Southern Flying Squirrel
• Dental formula 1/1 0/0 2/1 3/3 22
• Habitat Various deciduous forests with hollows
  and woodpecker holes throughout the eastern half
  of the United States
• Food nuts, seeds, berries, invertebrates, bird
  nestlings, and mammal flesh
• Reproduction Mate in early spring, gestate 41
  days, and have two litters of 2-7 young.
• Trivia Glaucomys are only nocturnal tree
  squirrels. Can glide through the air from tree
  to tree, or mistnet poles. Also run about on the
  ground, making them easy prey for snap-traps.
  Hurt if they bite ya.

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Key characters(Tree sciurids)

• Skins
• T. can grey, with 4 white and 3-5 brownish
  strips on upperparts
• T. hud Reddish color, length242, white ventor.
• S. niger Yellowish or Maroonish hairs (mutants
  common), Ttl534
• S. car White-tipped hairs, Ttl469
• S. abert Dark Gray with Maroon patch on back,
  Ear Tufts
• G. vol Hflt33, Ttllt250, Throat white at base

• Skulls
• T. can Skull lt 39mm
• T. hud Skulllt55mm, 3 septa visible in Bulla
• S. nig Skullgt55mm,1 lg U premolar
• S. car Skullgt55mm, 1 reduced U premolar1Lg.
• S. abert Skullgt55mm, 2 Lg U Premolars
• G. vol Cheek Teeth Parallel, Skulllt36mm, rounded
  skull

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Key characters(Ground sciurids)

• Skins
• S. tri 13 lines tail with hair, but not bushy
  scrawny
• S. fra Bushy Tail, Speckled appearance
• S. var Bushy tail, fur with wavy lines
• T. stri 5 black stripes and 2 light stripes on
  back, body rusty

• Skulls
• S. tri Very small premolar,Skulllt41mm
• S. fra Very small premolar, Skull 50-57 mm,
• S. var Very small premolar, Skullgt 57mm
• T. stri No infraorbital canal, No P3

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Key characters(Ground sciurids cont.)

• Skins
• A. inter small squirrel with one narrow white
  line on each side from shoulder to rump
• C. lud large and chunky, underparts pinkish
  cinnamon, tail tipped black
• S. spilo scattered white spots on back (not in
  rows)
• S. mex 9 rows of squarish white spots on back

• Skulls
• A. inter Aud bul large (1 ½ length molar row),
  1st premolar (P3) minute or absent
• C. lud Maxillary toothrow gt 14 mm, 1st upper
  premolar (P3) much broader than upper incisor
• S. spilo skull 34-42 mm length, Aud bul larger
  than S. tri.
• S. mex skull 41-52 mm length, zygomata larger
  than S. tri

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Family Geomyidae

• Four genera make up this group of fossorial
  rodents. This family, along with the
  heteromyids, are limited to the New World.
• Geomys
• Cratogeomys
• Pappogeomys
• Thomomys

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Geomys arenarius

• Desert Pocket Gopher
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat El Paso County TX, and adjacent
  counties in N Mex and Mexico in sandy river
  bottom areas
• Food Composite flowers and stems and cultivated
  alfalfa
• Reproduction Mate in March-May, producing 2 or
  3 litters of 4-6 young per litter after a 51 day
  gestation period.
• Trivia The mounds of this species, combined
  with their feces, is know to promote bunchgrass
  development in N Mex..

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Geomys bursarius

• Plains Pocket Gopher
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat sandy loam or prairie loam in the
  central United States
• Food fleshy roots, bulbs, and tender green
  plants, as well as shrub and tree roots
• Reproduction Mate in March-May, producing 2 or
  3 litters of 2-4 young per litter after a 51 day
  gestation period.
• Trivia These burrowing mammals are responsible
  for serious agriculturial damage, and have
  sparked the creation of many unique and
  interesting traps to kill them.

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Geomys personatus

• Texas Pocket Gopher
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat Disjunct populations in Del Rio, Dimmit
  Co., Karnes Co. south thru Rio Grande Plains in
  deep sandy soil. Absent from silty floodplain of
  Rio Grande River
• Food Roots of composites and grasses.
• Reproduction Breed year round? producing 2
  litters of 1-5 young per litter after a 50 day
  gestation period.
• Trivia Commonly undermine shoulders of highways
  in South TX, and promote erosion.

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Cratogeomys castanops

• Yellow-faced pocket gopher
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat deep sandy or silty soils lacking
  rocks, or displaced by G. bursarius into rockier
  terrain from Southern Kansas and Colorado,
  through West Texas and New Mexico into Mexico.
• Food fleshy roots and leaves from desert
  shrubs, as well as lechugilla (Agave lechugilla)
• Reproduction Bred in late fall/early spring and
  produce 2 litters of 1-5 young per litter.
• Trivia Water maybe an effective barrier to
  these gophers, as they have a reduced swimming
  ability to the other genera.

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Thomomys talpoides

• Northern pocket gopher
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat loose soils throughout the western half
  of the United States and southern Canada.
• Food Roots, tubers, bulbs, and succulents
• Reproduction Bred March-June, gestate about 28
  days, having 3-5 young in a litter.
• Trivia Although a better disperser that the
  other genera, this species tends to be displaced
  by the other genera.

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Key characters (Gophers)

• Skulls
• G. 2 grooves in incisor
• G. aren squmosal arm of zygoma ending in knob
  over jugal
• G. bur posterior end of zygomatic arch
  V-shaped w/ jugal
• G. per - posterior end of zygomatic arch
  U-shaped w/ jugal
• C. cast (also Papogeomys) 1 groove
• T. tal No grooves

• Skin
• All gophers can be readily recognized by their
  fusiform bodies, external cheek pouches, and
  digging claws.
• Unfortunately, they also rapidly evolve new skin
  colors to match their environments. Thus skins
  are virtually useless.
• Thomomys tends to be smaller, but not always

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Castor canadensis

• American Beaver
• Dental formula 1/1 0/0 1/1 3/3 20
• Habitat Any source of flowing water that can be
  dammed in eastern North America.
• Food bark from aspen, willows, maples, alders,
  apple, birth and others.
• Reproduction Mate in Jan-Feb with kits (4-5)
  born after 4 months of gestation. Two sets of
  young live with parents in lodge, with oldest
  set driven out before birth of newest young.
• Trivia Family Castoridae, this is one of two
  species, the other European. Nearly extirpated
  by 1900, reintroductions have been very
  successful, to the point of making this a pest
  animal in some cities.

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Family Muridae

• Around 20 genera
• Only introducing three this week in the genera
  Ondatra, Neotoma, and Rattus.
• The rest, along with the Dipodidae and the
  Heteromyidae, will be next week.
• HAHAHAHAHA

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Ondatra zibethicus

• Common muskrat
• Dental formula 1/1 0/0 0/0 3/3 16
• Habitat Prefer shallow watered marshes
  throughout much of Canada and the United States,
  with the exception of some southern states.
• Food roots and stalks of cattails, three-square
  grass, and Sagittaria, as well as leaves, stems,
  and fleshy roots of other aquatic plants. Will
  also take freshwater clams, fish, and crustacea.
• Reproduction Mate in winter, gestate 25-30
  days, and have litters of 3-8 young beginning in
  April. Young can swim in two weeks, weaned in a
  month, and independent after 3 months. Can have
  several litters a year.
• Trivia Can close their lips and cut with their
  incisors underwater. Also, an important fur crop.

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Neotoma cinerea

• Bushy-tailed woodrat
• Dental formula 1/1 0/0 0/0 3/3 16
• Habitat N. N Mex. and Ariz N to Mackenzie and
  Brit Columbia.
• Food green vegetation, fungi, moss, ferns,
  nuts, and acorns.
• Reproduction 1-4 young per litter, gestate
  33-42 days, having 1-2 litter per year
• Trivia This is the only species in the genus
  with a bushy squirrel-like tail.

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Neotoma mexicana

• Mexican woodrat
• Dental formula 1/1 0/0 0/0 3/3 16
• Habitat N cen CO and 4 corners S to Guatemala
  in rocky and mid-high elevations.
• Food green vegetation, fungi, moss, ferns,
  nuts, and acorns.
• Reproduction 2-5 young per litter, gestate
  33-42 days, and breed year round in the south.
  Females will produce litters within birth year,
  becoming sexually active within a month of birth.
• Trivia Builds extensive middens of food and
  water. This species also has a strong dislike of
  cactus, go figure.

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Neotoma micropus

• Southern Plains woodrat
• Dental formula 1/1 0/0 0/0 3/3 16
• Habitat Kansas and Colo S thru TX and N Mex to
  Mexico in brushlands of semiarid timberlands and
  deserts.
• Food prickly pear, sotol, agave, mesquite
  leaves and beans, and acorns. Get water from its
  food.
• Reproduction 1-2 litters per year, with 1-4
  young per litter, gestate about 30 days, and
  breed year round in the south. Mature after 300
  days.
• Trivia This species readily hybridizes with N.
  floridanus in OK and N. albigula along its
  eastern border.

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Rattus rattus

• Roof rat
• Dental formula 1/1 0/0 0/0 3/3 16
• Habitat Anywhere that food and shelter is
  abundant from fields, dumps, or homes throughout
  the world
• Food grain, fruits, human foods, anything
  edible
• Reproduction Bred year round, and gestate about
  21 days, having 2-14 young. Wean at 3 weeks, and
  can become reproductive at 3 months.
• Trivia More common that the larger and more
  aggressive Norway rat in the southern US, but R.
  norvegicus is on the move.

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Key characters (Big uns)

• Skins
• C. can Webbed feet, Dorso-ventrally Flat tail
• E. dor OUCH, spiny
• M. corp Laterally flat tail, coarse fur, Lg
  Sizegt500mm
• O. zib rounded tail, soft underfur with long
  gaurdhairs, Ttl 537
• R. rat Coarse fur, scaly tail, Small eyes,
  ventor similar to dorsum

• Skulls
• C. can Flask-shaped bulla point outup,
  Basioccipital pit
• E. dor Huge Infraorbital foramen. First cheek
  tooth is largest. Short Paraoccipital process.
• M. corp Huge infraorbital foramen, Paraoccipital
  process long, and well developed. Largest cheek
  tooth is last molar,
• O. zib Skull gt 52mm length, width of upper
  incisor gt 3mm
• R. rat Cheek teeth with 3 rows of cusps, skull
  gt 20mm

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Key characters (Big uns cont.)

• Skins
• N. cin Bushy tail
• N. mex tail brown above, white below underparts
  of fur buffy basally
• N. micro tail black above, gray below
  underparts white

• Skulls
• N. cin M1 w/ deep anterio-internal angle, M3
  with closed triangle and 2 loops
• N. mex M1 w/ a deep anterio-internal angle
• N. micro M1 w/ a shallow anterio-internal angle