Animals are either homeothermic or poikilothermic (homeo-same, poikilo-varied, thermoc-warm), more commonly known as "warm-blooded" or "cold-blooded", respectively. Homeothermic animals include mammals and birds. Examples of poikilothermic species would include the invertebrates, reptiles, fish, amphibians, etc. Using what you have learned about respiration and enzymes, explain why poikilotherms move more slowly in the winter than the summer.