“I love frogs because they’re just so freakin’ cute.” This Awesome Statement of Awesomeness was uttered by my boss’s 8-year-old daughter. Then, I’m afraid I undermined my boss’s authority by cracking up. I have to agree with her, frogs (and salamanders and snakes and lizards and iguanas all) are really, really cute. I want to study them and have them as pets and hug them and hold them and feed them and ……. I just really think they’re awesome, ok?!
However, I don’t think they (the frogs, salamanders, snakes and lizards, hereafter referred to as herpetofauna) have what it takes to be intelligent. One of the major differences between us and them is that we produce internal heat by metabolism, which we call endothermy. Birds and the other mammals share this trait with us. Herpetofauna and just about every other creature on earth do not.
Why is this important? Our brain operates in a very narrow range of temperatures (95-100 degrees Farhenheit). If we get too hot our brain cells do funny things like die. Hypothermia, the other end of the spectrum, results in low oxygen in the brain, which is also bad for you. In order to operate our brain at maximum efficiency, we need to keep it in the ideal range. Herpetofauna on the other hand cannot produce their own heat in most cases, nor do they have effective mechanisms for dealing with too much heat. Their means of gaining and/or losing heat are all behavioral (sitting in the shade or sun, going swimming, etc.). As such they cannot maintain a constant temperature most of the time and their brains do not operate at maximum efficiency.
Most of the animals displaying characteristics approaching intelligence, elephants, primates, dolphins, whales and crows, are endothermic. There is one big exception to this statement. Octopi are the major invertebrate “smart” animal. They are not endothermic and yet they are smart enough to outplan two graduate students. However, they live in an environment with a relatively stable temperature. They don’t need to produce heat to maintain a stable temperature because the unique chemical nature of water does that for them.
What does this mean for extra-terrestrials? On a stable planet, with a (relatively) stable temperature, intelligent life forms would not need to produce their own heat, which is metabolically expensive. Intelligent life forms from that planet could be lizard/frog-like. Which would be so COOL!! On a variable planet like ours, however, intelligent life would probably be more like mammals or birds.