| Species (N=918) | GC (%) | AT (%) | G (bases) | C (bases) | A (bases) | T (bases) | Maximum lifespan (yrs) | 
|---|---|---|---|---|---|---|---|
| Coregonus clupeaformis | 51.3 | 48.7 | 186 | 82 | 66 | 188 | 50.0 | 
| Coregonus nasus | 51.0 | 49.0 | 185 | 81 | 66 | 190 | 15.0 | 
| Corvus brachyrhynchos | 46.9 | 53.1 | 178 | 67 | 84 | 193 | 20.0 | 
| Corvus cornix | 47.5 | 52.5 | 183 | 65 | 80 | 194 | 16.8 | 
| Corvus frugilegus | 45.6 | 54.4 | 173 | 65 | 87 | 197 | 22.9 | 
| Corvus hawaiiensis | 45.6 | 54.4 | 173 | 65 | 88 | 196 | 25.0 | 
| Cottus poecilopus | 49.6 | 50.4 | 175 | 84 | 76 | 187 | 8.0 | 
| Coturnix chinensis | 44.8 | 55.2 | 192 | 42 | 59 | 229 | 5.0 | 
| Coturnix japonica | 45.8 | 54.2 | 197 | 42 | 63 | 220 | 6.0 | 
| Crax rubra | 49.8 | 50.2 | 209 | 51 | 51 | 211 | 24.0 | 
| Crocidura russula | 34.3 | 65.7 | 136 | 47 | 141 | 210 | 4.0 | 
| Crocodylus acutus | 43.9 | 56.1 | 180 | 52 | 82 | 214 | 32.9 | 
| Crocodylus intermedius | 44.5 | 55.5 | 180 | 55 | 82 | 211 | 21.8 | 
| Crocodylus moreletii | 45.5 | 54.5 | 180 | 60 | 84 | 204 | 25.4 | 
| Crocodylus niloticus | 44.3 | 55.7 | 178 | 56 | 85 | 209 | 43.8 | 
| Crocodylus novaeguineae | 44.4 | 55.6 | 182 | 51 | 82 | 210 | 24.6 | 
| Crocodylus palustris | 44.9 | 55.1 | 176 | 61 | 87 | 204 | 31.5 | 
| Crocodylus porosus | 43.8 | 56.3 | 181 | 50 | 85 | 212 | 41.7 | 
| Crocodylus rhombifer | 43.9 | 56.1 | 174 | 58 | 88 | 208 | 38.2 | 
| Crocodylus siamensis | 43.2 | 56.8 | 183 | 45 | 83 | 217 | 21.9 | 
| Crocuta crocuta | 40.5 | 59.5 | 159 | 55 | 100 | 214 | 41.1 | 
| Crotalus horridus | 44.1 | 55.9 | 191 | 39 | 69 | 223 | 30.2 | 
| Ctenopharyngodon idella | 42.1 | 57.9 | 161 | 59 | 78 | 224 | 21.0 | 
| Culaea inconstans | 44.1 | 55.9 | 161 | 69 | 78 | 214 | 2.0 | 
| Cuon alpinus | 37.5 | 62.5 | 144 | 54 | 118 | 212 | 16.1 | 
| Cuora amboinensis | 37.7 | 62.3 | 156 | 42 | 79 | 248 | 38.2 | 
| Cuora flavomarginata | 39.6 | 60.4 | 165 | 43 | 73 | 244 | 19.1 | 
| Cuora trifasciata | 39.6 | 60.4 | 162 | 46 | 73 | 244 | 31.8 | 
| Cyclemys dentata | 38.3 | 61.7 | 159 | 42 | 79 | 245 | 14.7 | 
| Cycleptus elongatus | 46.9 | 53.1 | 163 | 82 | 75 | 202 | 13.0 | 
| Cygnus columbianus | 49.0 | 51.0 | 198 | 58 | 57 | 209 | 24.1 | 
| Cygnus cygnus | 49.8 | 50.2 | 198 | 62 | 58 | 204 | 26.5 | 
| Cygnus olor | 51.5 | 48.5 | 206 | 63 | 52 | 201 | 70.0 | 
| Cymatogaster aggregata | 45.0 | 55.0 | 167 | 68 | 93 | 194 | 8.0 | 
| Cynomys ludovicianus | 36.2 | 63.8 | 154 | 36 | 122 | 213 | 11.0 | 
| Cynopterus brachyotis | 39.8 | 60.2 | 169 | 41 | 105 | 213 | 10.1 | 
| Cyprinella lutrensis | 46.4 | 53.6 | 156 | 86 | 97 | 183 | 2.0 | 
| Cyprinella spiloptera | 48.3 | 51.7 | 163 | 89 | 99 | 171 | 5.0 | 
| Cyprinus carpio | 43.7 | 56.3 | 164 | 63 | 73 | 219 | 47.0 | 
| Daboia russellii | 37.8 | 62.2 | 169 | 27 | 93 | 230 | 15.0 |