While walking on the pavements during the early morning sun, have you spotted some lizards sunning themselves in the open?

OK, for those who have already given back biology to their teachers, lizards are reptiles and reptiles are cold-blooded animals.

Which means they do not have their own “internal combustion engine” inside their bodies to generate heat. They need to “sun” themselves to warm their bodies up. That’s is why on cloudy days, you don’t see reptiles running around…

What’s the benefit in that?

With a lower resting metabolism rate, reptiles need less fuel to sustain their bodily functions. For eg, a crocodile needs only 1/7 of what a lion of the same weight needs for food, and can go half a year without eating.  


Mammals are warm-blooded animals. And yes, that include us. In contrast to reptiles, we have our own “internal combustion engine” inside us. 

We generate our own heat.

It’s an advantage whether we are a predator chasing after our food, or as prey running from our predators.

Can you imagine when you need to act immediately, and you go, “Wait, give me 2 more hours in the sun and I’ll be good to go!”

Either the opportunity has passed you by or you are already dead meat…

The drawback? We mammals “eat fuel heavy heavy”. We are fuel guzzlers compared to reptiles.

Hence the need to constantly look for food and prey every day due to our higher metabolism rate.

The constant hunger…

The allegory

(Please fill in the blanks yourself)

There! You now know whether you are cold-blooded or warm-blooded! Wink.

Singapore Man of Leisure (welcome to my blog; just google it!)