 Based on these estimations, the study concluded that large dinosaurs were inertial homeotherms (their temperatures were stabilized by their sheer bulk) and that dinosaurs were ectothermic (in colloquial terms, "cold-blooded", because they did not generate as much heat as mammals when not moving or digesting food).These results are consistent with the relationship between dinosaurs' sizes and growth rates (described above).Studies of the sauropodomorph "Massospondylus" and early theropod "Syntarsus" ("Megapnosaurus") reveal growth rates of 3 kg/year and 17 kg/year, respectively, much slower than those estimated of "Maiasaura" and observed in modern birds.