An example of an endothermic animal would be a dog and an ectothermic animal would be a snake. Endothermic animals must generate their own heat to stay warm and ectothermic animals can warm up using outside sources like the sun.
All mammals are endothermic, or warm-blooded creatures. Endotherms unconsciously use their metabolism as a way of regulating body temperature.
Ectotherms, or cold-blooded animals such as reptiles, most fish and amphibians, must rely on outside sources to warm up or cool down their body temperature. These animals can often be seen hanging out in the shade when it's hot, or sunning themselves on a cool morning.