| Species (N=919) | GC (%) | AT (%) | G (bases) | C (bases) | A (bases) | T (bases) | Maximum lifespan (yrs) | 
|---|---|---|---|---|---|---|---|
| Martes foina | 45.5 | 54.5 | 238 | 119 | 213 | 214 | 18.2 | 
| Martes martes | 45.4 | 54.6 | 231 | 125 | 218 | 210 | 18.2 | 
| Martes pennanti | 44.1 | 55.9 | 229 | 117 | 221 | 217 | 14.3 | 
| Martes zibellina | 45.8 | 54.2 | 235 | 124 | 214 | 211 | 18.4 | 
| Mauremys japonica | 41.6 | 58.4 | 208 | 118 | 217 | 241 | 16.2 | 
| Mauremys mutica | 42.8 | 57.2 | 215 | 121 | 212 | 237 | 22.1 | 
| Mazama americana | 41.7 | 58.3 | 211 | 116 | 251 | 206 | 17.1 | 
| Mecistops cataphractus | 44.8 | 55.2 | 221 | 130 | 207 | 226 | 56.1 | 
| Megalops atlanticus | 47.0 | 53.0 | 243 | 126 | 203 | 213 | 55.0 | 
| Megalops cyprinoides | 48.4 | 51.6 | 247 | 133 | 193 | 212 | 44.0 | 
| Megaptera novaeangliae | 43.4 | 56.6 | 226 | 115 | 228 | 217 | 95.0 | 
| Melamprosops phaeosoma | 47.4 | 52.6 | 252 | 120 | 196 | 216 | 9.2 | 
| Melanogrammus aeglefinus | 41.1 | 58.9 | 191 | 132 | 260 | 203 | 20.0 | 
| Meleagris gallopavo | 45.1 | 54.9 | 236 | 119 | 213 | 219 | 13.0 | 
| Meles meles | 42.6 | 57.4 | 214 | 120 | 241 | 209 | 18.6 | 
| Melogale moschata | 46.3 | 53.7 | 239 | 124 | 216 | 205 | 19.0 | 
| Melopsittacus undulatus | 46.6 | 53.4 | 256 | 109 | 188 | 231 | 21.0 | 
| Melursus ursinus | 46.3 | 53.7 | 226 | 137 | 221 | 200 | 33.3 | 
| Menidia menidia | 50.4 | 49.6 | 251 | 145 | 216 | 173 | 2.0 | 
| Mephitis mephitis | 41.5 | 58.5 | 203 | 122 | 233 | 226 | 13.9 | 
| Meriones unguiculatus | 40.8 | 59.2 | 201 | 119 | 239 | 225 | 6.3 | 
| Merlangius merlangus | 41.6 | 58.3 | 199 | 128 | 249 | 209 | 20.0 | 
| Merluccius merluccius | 51.0 | 49.0 | 262 | 139 | 192 | 193 | 20.0 | 
| Mesocricetus auratus | 39.5 | 60.5 | 194 | 116 | 258 | 216 | 3.9 | 
| Mesoplodon europaeus | 41.1 | 58.9 | 218 | 105 | 246 | 216 | 48.0 | 
| Metachirus nudicaudatus | 36.6 | 63.4 | 174 | 113 | 269 | 228 | 3.0 | 
| Microhyla ornata | 43.5 | 56.5 | 209 | 132 | 251 | 192 | 5.0 | 
| Micromesistius poutassou | 45.2 | 54.8 | 226 | 129 | 229 | 202 | 20.0 | 
| Micropterus dolomieu | 49.7 | 50.3 | 250 | 140 | 210 | 185 | 26.0 | 
| Micropterus salmoides | 47.7 | 52.3 | 235 | 140 | 226 | 185 | 23.0 | 
| Micrurus fulvius | 45.3 | 54.7 | 227 | 128 | 207 | 222 | 19.0 | 
| Minytrema melanops | 43.8 | 56.2 | 218 | 126 | 222 | 220 | 6.0 | 
| Mogera wogura | 40.2 | 59.8 | 197 | 118 | 234 | 235 | 3.2 | 
| Monodelphis domestica | 38.8 | 61.2 | 188 | 116 | 259 | 221 | 5.1 | 
| Monodon monoceros | 42.9 | 57.1 | 234 | 103 | 229 | 220 | 50.0 | 
| Morone saxatilis | 45.6 | 54.4 | 224 | 134 | 229 | 198 | 30.0 | 
| Mugil cephalus | 46.2 | 53.8 | 237 | 125 | 216 | 206 | 16.0 | 
| Muntiacus muntjak | 42.5 | 57.5 | 217 | 116 | 241 | 210 | 18.8 | 
| Muntiacus reevesi | 42.6 | 57.4 | 220 | 114 | 235 | 215 | 23.2 | 
| Mus musculus | 38.9 | 61.1 | 197 | 108 | 245 | 234 | 4.0 |