Physiology and endocrinology have big roles in regulating behavior. Hello, hormones, take me to prom? We’ll get to that in a minute. Hormones and physiology make animals do things. They make us hungry, thirsty, tired, alert, and ready to mate, just as part of their daily job.
Animal physiology varies greatly and this affects behavior. Warm-blooded mammals can do things very differently than cold-blooded reptiles. Warm-blooded animals can afford to exert more energy on hunting than cold-blooded animals. Cold-blooded animals cannot expend energy chasing prey for hours. Reptiles spend a lot of time basking in the sun because they can’t regulate their own body temperatures as well as warm-blooded animals can.
The time of day an animal is active depends on its physiology too. Nocturnal animals have special features that make them good at navigating the night—for example, cats can see well in the dark, allowing them to hunt at night. Cat physiology allows them to see in the dark—like many nocturnal animals, they have large eyes, large pupils, and protect their eyes from bright light during the day by having a slit pupil. Look at a cat’s eye. See how the pupil (the dark part) is a slit?
Now go look at your eye in the mirror. Your pupils are round, or if they aren’t you better go see a doctor. Image from here.
In the desert, daytime temperatures are oppressively hot, so animal behavior and physiology are tightly linked. Most desert animals are nocturnal, sleeping during the hottest part of the day and foraging at night. However, if everyone is awake at night, that means predation risk is high at night. In the Sahara desert, one the most heat tolerant animals on the planet can be active during the day. It is the Sahara desert ant and it can survive in temperatures up to 122º Fahrenheit. And we thought 80º was hot. Desert ants have a few physiological adaptations that allow them to deal with this heat. They have longer legs than other ants, which hold their bodies away from the hot ground. Their bodies produce heat shock proteins before leaving the nest to protect cellular function in extreme heat. And of course, they work in groups to drag food back to the nest.
The thing is, even this little heat tolerant ant can only spend 3-5 minutes in the extreme heat before getting fried. So everyday when the sun is highest and all the other animals hide in cooler spots, Sahara desert ants leave the nest to forage. These ants monitor their location in relation to the sun’s position in the sky, always knowing the shortest route back to the nest. Check out the BBC’s video clip of these ants foraging.