Question

which factor decide does whether the animal is cold blooded or warm blooded

Answer 1

To generate heat, warm-blooded animals convert the food that they eat into energy. They have to eat a lot of food, compared with cold-blooded animals, to maintain a constant body temperature. ... Cold-blooded creatures take on the temperature of their surroundings

Answer 2

Animals which do not have constant body temperature.

That means there bodies get cooler in night and when the sun is out their bodies get warmer in temp are called cold blooded animals.

Examples are reptiles and amphibians.

Whereas,

Animals which do have constant body temperature are called warm blooded temperatures like mammals.