What we ve covered so far:

Transcription

1 What we ve covered so far: Didelphimorphia Didelphidae opossums (1 B.C. species) Soricomorpha Soricidae shrews (9 B.C. species) Talpidae moles (3 B.C. species)

2 What s next: Rodentia Sciuridae squirrels (16) Muridae mice, rats, lemmings, voles (16) Aplodontidae mountain beaver (1) Castoridae beaver (1) Dipodidae jumping mice (2) Erethizontidae N. American porcupines (1) Geomyidae pocket gophers (1) Heteromyidae kangaroo rats, pocket mice (1)

3 Rodent diversity

4 Order Rodentia Dentition highly specialized for gnawing Incisors: o o o single pair of upper, single pair of lower grow continuously (rootless) enamel on anterior surface, not posterior surface

5 Order Rodentia Dentition highly specialized for gnawing Incisors Diastema No canines

6 Family Sciuridae

7 Family Sciuridae Postorbital process well-developed Rostrum short, arched Infraorbital canal reduced relative to many other rodents 1/1 0/0 1-2/1 3/3, anterior premolar sometimes small and peg-like

8 Glaucomys sabrinus northern flying squirrel Can glide 5-25 meters Strictly nocturnal Share nests, reduce activity in winter because of cold

9 Glaucomys sabrinus northern flying squirrel Conspicuous notch anterior to postorbital process 5 upper cheekteeth

10 Marmota spp. marmots and woodchuck

11 Marmota spp. marmots and woodchuck Rows of cheek teeth parallel, or nearly so Postorbital processes protrude at 90

12 Marmota spp. marmots and woodchuck M. monax M. vancouverensis M. caligata M. flaviventris

13 Marmota monax - woodchuck Posterior border of nasals forms a V Maxillary row < 21 mm

14 Marmota vancouverensis Vancouver Island marmot Posterior border of nasals forms a V Maxillary row > 21 mm

15 Marmota caligata hoary marmot Posterior border of nasals forms an arch Maxillary row > 21 mm

16 Marmota flaviventris yellow-bellied marmot Posterior border of nasals forms an arch Maxillary row < 21 mm

17 Sciurus carolinensis eastern gray squirrel Dorsal pelage variable (often gray, but can be light-colored or even black) Long bushy tail (>50% body length)

18 Sciurus carolinensis eastern gray squirrel 5 upper cheekteeth; P1 small and peg-like Infraorbital foramen a canal on the side of the rostrum 2 transbullar septae

19 Spermophilus spp. ground squirrels, rock squirrels 5 cheekteeth per side no peg-like cheekteeth Flattened zygomatic plate

20 Spermophilus spp. ground squirrels, rock squirrels Maxillary toothrow > 10 mm S. columbianus S. parryii Maxillary toothrow < 10 mm S. lateralis S. saturatus

21 Spermophilus columbianus Columbian ground squirrel Range: southern BC interior east of Rockies Concerns about poisoning by ranchers worried about competition with livestock Side of neck grayish

22 Spermophilus parryii Arctic ground squirrel Range: northwest BC Highly colonial, with hundreds of animals per colony and a few dominant males Eat carcasses of animals Side of neck reddish Ventral side of tail reddish with black tip

23 Spermophilus lateralis golden-mantled ground squirrel Range: Rocky Mountains Prominent black stripes bordering light stripes on back and mantle Unlike chipmunks, no stripes on face

24 Spermophilus saturatus Cascade mantled ground squirrel Range: southern Cascades (limited range could pose conservation risk) Black stripes on back; mantle inconspicuous Unlike chipmunks, no stripes on face

25 Tamias spp. - chipmunks

26 Tamias spp. - chipmunks 5 upper cheekteeth; P1 small and peg-like Infraorbital canal pierces zygomatic plate

27 Tamias townsendii Townsend s chipmunk Skull length > 37 mm Maxillary toothrow length > 6 mm Pale, indistinct stripes on back and head

28 Tamias minimus least chipmunk Skull length < 33 mm, toothrow < 6 mm Total length < 195 mm Distinct stripes on back and head Range: northern half of BC

29 Tamias amoenus yellow-pine chipmunk Skull length mm, toothrow < 6 mm Total length > 195 mm Distinct stripes on back and head Range: southern half of BC

30 Tamias ruficaudus red-tailed chipmunk Skull length mm, toothrow < 6 mm Total length > 195 mm Distinct stripes on back and head Range: extreme southeastern BC

31 Tamiasciurus spp. American red squirrels 4 upper cheekteeth Zygomatic arches parallel or nearly so 3 transbullar septae

32 Tamiasciurus douglasii Douglas squirrel Ventral pelage yellow or orange Range: southwestern BC

33 Tamiasciurus hudsonicus North American red squirrel Ventral pelage white or gray Range: most of BC including Vancouver Island

34 Red squirrel midden