Why is it that we never pause in our day to enjoy the song of the mouse, but we stop to listen to the song of a meadowlark? No one writes poems about the serenade of a ground squirrel or the vocal talents of a raccoon as they do of nightingales and thrushes.
Instead we speak of squeaks, chatter, grunts and hisses when referring to the sounds of mammals, hardly vocalizations that inspire. In our region I can think of only the howling of coyotes as a mammalian sound to be enjoyed, although some people have a very different reaction. The bugling of an elk is another mammalian sound that causes some to pause, but to wax poetic?
It doesn't get much prettier when we consider other vertebrates. When is the last time you heard a snake or turtle sing? We have to turn to amphibians to find other vertebrates that use sound to communicate, and even then it is only the frogs and toads. Salamanders are nearly silent. The chorus of tree frogs in a cool April night is as enjoyable to me as the twilight serenade of a robin that precedes it.
I understand some fish vocalize on coral reefs, but I'm not sure this qualifies as singing. I'm still waiting to hear my first salmon aria.
Crickets and cicadas try to uphold the honor of insects in the realm of sounds, but they are very much in the minority. Butterflies, dragonflies, ants and beetles are largely silent, at least to our ears. What a select and diverse group of singers: birds, frogs and crickets! I suppose we should add humans to the list.
Returning to mammals and birds, why the difference in use of voice? I don't have a good answer.
Being diurnal animals and active when the world is bathed in light, birds rely on vision as their dominant sense to find food and navigate. However, when it comes time to advertise for a mate or claim a territory, a great many turn to sound. Why? Logically, I say go with your strength — stay with those beautiful feathers and dazzle and intimidate visually. Song seems like an unnecessary extravagance for a stunning robin, tanager or bunting, not that I'm complaining.
Mammals on the other hand are largely nocturnal and reasonably rely on other senses in a dark world, especially their sense of smell. Odors help them find meals and mates, as well as mark territories. However, the sense of smell has limitations. First, it is directional. If you are up wind, you miss the message. Second, it takes time for scents to move about on the wind, unlike light and sound, which arrive almost immediately.
Sound is an excellent way to communicate in the dark, so I say mammals should sing. They have excellent ears to hear lyrics and riffs. The hearing of dogs and bats is legendary. So why not sing away the night the way birds fill a spring morning? I don't get it. No, mammals leave it to wolves and humpback whales to add their voices to the chorus of life.
You can already hear the first songs of spring, though it will be awhile before it is in full voice. Take a walk and enjoy. And while you are there, give a few words of encouragement to the neighborhood squirrel and opossum.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached at firstname.lastname@example.org.