| Species (N=919) | GC (%) | AT (%) | G (bases) | C (bases) | A (bases) | T (bases) | Maximum lifespan (yrs) |
|---|---|---|---|---|---|---|---|
| Martes foina | 42.1 | 57.9 | 203 | 84 | 189 | 205 | 18.2 |
| Martes martes | 42.7 | 57.3 | 210 | 81 | 185 | 205 | 18.2 |
| Martes pennanti | 40.7 | 59.3 | 202 | 75 | 194 | 210 | 14.3 |
| Martes zibellina | 43.6 | 56.4 | 210 | 87 | 185 | 199 | 18.4 |
| Mauremys japonica | 39.0 | 61.0 | 201 | 66 | 180 | 237 | 16.2 |
| Mauremys mutica | 38.5 | 61.5 | 192 | 71 | 192 | 229 | 22.1 |
| Mazama americana | 38.5 | 61.5 | 181 | 81 | 207 | 212 | 17.1 |
| Mecistops cataphractus | 39.9 | 60.1 | 210 | 68 | 180 | 238 | 56.1 |
| Megalops atlanticus | 45.2 | 54.8 | 215 | 94 | 175 | 199 | 55.0 |
| Megalops cyprinoides | 45.2 | 54.8 | 217 | 92 | 175 | 199 | 44.0 |
| Megaptera novaeangliae | 40.1 | 59.9 | 206 | 67 | 189 | 219 | 95.0 |
| Melamprosops phaeosoma | 44.6 | 55.4 | 241 | 64 | 166 | 213 | 9.2 |
| Melanogrammus aeglefinus | 37.6 | 62.4 | 175 | 82 | 242 | 185 | 20.0 |
| Meleagris gallopavo | 43.9 | 56.1 | 230 | 70 | 193 | 191 | 13.0 |
| Meles meles | 37.7 | 62.3 | 182 | 75 | 208 | 216 | 18.6 |
| Melogale moschata | 41.7 | 58.3 | 197 | 87 | 197 | 200 | 19.0 |
| Melopsittacus undulatus | 44.7 | 55.3 | 247 | 59 | 168 | 210 | 21.0 |
| Melursus ursinus | 43.0 | 57.0 | 190 | 103 | 206 | 182 | 33.3 |
| Menidia menidia | 48.0 | 52.0 | 233 | 95 | 192 | 164 | 2.0 |
| Mephitis mephitis | 39.4 | 60.6 | 191 | 77 | 203 | 210 | 13.9 |
| Meriones unguiculatus | 36.0 | 64.0 | 172 | 73 | 215 | 221 | 6.3 |
| Merlangius merlangus | 37.3 | 62.6 | 174 | 81 | 239 | 189 | 20.0 |
| Merluccius merluccius | 48.2 | 51.8 | 244 | 86 | 185 | 169 | 20.0 |
| Mesocricetus auratus | 35.7 | 64.3 | 173 | 70 | 218 | 220 | 3.9 |
| Mesoplodon europaeus | 38.5 | 61.5 | 197 | 65 | 199 | 220 | 48.0 |
| Metachirus nudicaudatus | 33.2 | 66.8 | 164 | 62 | 231 | 224 | 3.0 |
| Microhyla ornata | 37.8 | 62.2 | 179 | 79 | 249 | 175 | 5.0 |
| Micromesistius poutassou | 45.7 | 54.3 | 216 | 96 | 193 | 177 | 20.0 |
| Micropterus dolomieu | 47.1 | 52.9 | 223 | 99 | 203 | 158 | 26.0 |
| Micropterus salmoides | 45.5 | 54.5 | 220 | 91 | 208 | 165 | 23.0 |
| Micrurus fulvius | 38.6 | 61.1 | 203 | 59 | 185 | 230 | 19.0 |
| Minytrema melanops | 36.8 | 63.2 | 162 | 90 | 223 | 209 | 6.0 |
| Mogera wogura | 36.3 | 63.7 | 174 | 73 | 211 | 223 | 3.2 |
| Monodelphis domestica | 35.5 | 64.5 | 176 | 66 | 210 | 229 | 5.1 |
| Monodon monoceros | 39.4 | 60.6 | 205 | 63 | 190 | 223 | 50.0 |
| Morone saxatilis | 47.2 | 52.8 | 224 | 99 | 214 | 147 | 30.0 |
| Mugil cephalus | 44.7 | 55.3 | 227 | 78 | 195 | 183 | 16.0 |
| Muntiacus muntjak | 38.6 | 61.4 | 183 | 80 | 206 | 212 | 18.8 |
| Muntiacus reevesi | 39.2 | 60.8 | 185 | 82 | 204 | 210 | 23.2 |
| Mus musculus | 36.0 | 64.0 | 179 | 66 | 204 | 232 | 4.0 |