We humans are endotherms; we create body heat by breaking down food. Our high metabolism keeps our core temperature right around 97.8 degrees. This body temperature is an indication of how fast the molecules in our cells are moving at all times. Although we experience cold and hot seasons, the difference in temperatures doesn’t affect how our bodies work.
To remain active cold blooded creatures such as lizards and snakes must seek sunshine in the morning. Reptiles get their muscle cells working and overcome the sluggishness brought on by cooler night time temperatures by absorbing heat from sunbeams or sun warmed rock. (Some of us endotherms drink coffee to the same effect.) When it gets too hot, cold blooded animals move into the shade or even retreat to burrows, which is why you won’t see reptiles out moving around at midday in the summer. Amphibians such as frogs, toads and salamanders also seek the sun’s warmth to get moving, basking on the sunlit banks of streams. Butterflies and moths are languid on chilly mornings and settle at sunrise with their wings positioned for maximum absorption of the early rays. Honey bees and bumble bees vibrate flight muscles to quickly warm up and fuel their nectar finding expeditions.
Once body temperatures are brought into their sweet spot cold blooded animals enjoy lightning fast reflexes. The attainment of perfect body temperatures also aids digestion, allowing ectotherms to gain the most nutrients from their food. In short, a toasty warm ectotherm is a happy cold blooded animal. We don’t have wood frogs around here, but these amazing amphibian ectotherms freeze solid in the winter. Ice crystals actually form in their body cavities and their hearts stop beating. As the chill of winter sets in, glucose floods their systems keeping the vital organs viable. Come spring wood frogs thaw out good as new. See frogsaregreen.org.
In case you are wondering, the phrase cold blooded murder came about in the 1700’s when it was believed that emotions affected the temperature of a person’s blood. A person who appeared detached and ruthless was considered cold blooded, while a hot blood was ruled by their passions.