The researchers concluded that the ancestors of living crocodilians had fully 4-chambered hearts, and were therefore warm-blooded, before they reverted to a cold-blooded or ectothermic metabolism.
42.
Ectothermic ( i . e . cold-blooded ) animals have to ensure that their internal chemistry stays in balance over the whole range of temperatures that the animal is expected to tolerate.
43.
Perhaps owing to the greater presence of cold-blooded ( ectothermic ) reptiles in warmer climates, the states in the southern half of the United States have more commonly designated a state reptile.
44.
Because they are nearly transparent, their internal organs are easy to study in live specimens ( e . g . to study the effect of temperature on the heart rate of these ectothermic organisms ).
45.
It is no coincidence that all of these states are in the southern part of the country; reptiles and amphibians are ectothermic ( cold blooded ) and thus are typically more abundant in warmer climates.
46.
The idea of dinosaurs as ectothermic and sluggish remained a prevalent view until Robert T . " Bob " Bakker, an early proponent of dinosaur endothermy, published an influential paper on the topic in 1968.
47.
Most bony fishes are ectothermic, or cold-blooded, but this species, much like the related tunas, is endothermic and is able to raise its body temperature to achieve a degree of thermoregulation.
48.
Rattlesnakes are found in almost every type of habitat capable of supporting terrestrial ectothermic vertebrates, but individual species can have extremely specific habitat requirements, only able to live within certain plant associations in a narrow range of altitudes.
49.
J . S . Alho and colleagues argued that tibia and femur lengths are highest in populations of the Common Frog that are indigenous to the middle latitudes, consistent with the predictions of Allen's rule for ectothermic organisms.
50.
Most fish are ectothermic ( " cold-blooded " ), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature.
