Colorado Herpetological Society
Colorado's Amphibians
by Lauren J. Livo
Evaluate the criteria below to identify a species.

1a. Adult with long tail, aquatic larvae with conspicuous gills on sides of head. Ambystoma tigrinum
Tiger salamander
1b. Adult lacking tail. go to 2
2a. Skin warty, prominent parotoid glands behind eyes. go to 3
2b. Skin relatively smooth, no parotoid glands. go to 7
3a. Light mid-dorsal stripe. go to 4
3b. No light mid-dorsal stripe. go to 6
4a. Large symmetrical dark blotches on back. Bufo cognatus
Great Plains toad
4b. Not as above. go to 5
5a. No cranial crests, usually above 8,000'. Anaxyrus boreas boreas
Boreal toad
5b. Cranial crests, usually below 7,000'. Bufo woodhousii
Woodhouse's toad
6a. Parotoid glands nearly circular, body tan or gray with red warts. Bufo punctatus
Red-spotted toad
6b. Body green with scattered dark spots. Bufo debilis
Green toad
7a. Head small with fold of skin behind eyes. Gastrophryne olivacea
Great Plains
narrowmouth toad
7b. Not as above. go to 8
8a. Vertical pupils; rear feet each with single, hard dark 'spade'. go to 9
8b. Pupils and rear feet not as above. go to 12
9a. Boss between eyes. go to 10
9b. No boss between eyes. go to 11
10a. Boss hard, mostly eastern Colorado. Spea bombifrons
Plains spadefoot
10b. Boss pliable, western Colorado. Spea intermontana
Great Basin spadefoot
11a. Body greenish-yellow with dark blotches; snout-vent length may exceed 2.5 inches. Scaphiopus couchii
Couch's spadefoot
11b. Body gray or brown with dark spots; snout-vent length up to 2.5 inches. Spea multiplicata
New Mexico spadefoot
12a. Conspicuous dorsolateral folds. go to 13
12b. No dorsolateral folds. go to 15
13a. Dark mask through eye from snout to angle of jaw, usually light mid-dorsal stripe, north-central Colo. Rana sylvatica
Wood frog
13b. No mid-dorsal stripe, dark spots on body. go to 14
14a. Dorsolateral folds continuous from eye to groin, body green or brown. Rana pipiens
Northern leopard frog
14b. Dorsolateral folds broken and inset near groin, body always brown. Rana blairi
Plains leopard frog
15a. Toepads distinctly enlarged. Hyla arenicolor
Canyon treefrog
15b. Not as above. go to 16
16a. Fold of skin around top of eardrum; body size may exceed 7 inches. Rana catesbeiana
16b. Maximum body size less than 1.5 inches. go to 17
17a. Stripe through eye from snout to groin, usually three stripes on back (may be spotted), little webbing on hind feet. Pseudacris triseriata
Chorus frog
17b. Triangular spot between eyes, extensive webbing on hind feet. Acris crepitans
Northern cricket frog