Page "Singing" Paragraph 85

Joseph Jordania has suggested that singing behavior is very unevenly distributed among animal species, living in different environments ( on the ground, in the water, in trees ).

Most of the singing species live on the trees ( like many bird species, or gibbons ), some live in the water ( whales, dolphins, seals, sea lions ), and there are no animal species who live on the ground and sing except for humans.

This uneven distribution of singing can be crucial for our understanding of the origins of the singing behavior in animals and humans.

Jordania explains this fact as the result of the pressure from natural selection.

Singing is a very costly behavior, not only because of the energy to produce sounds, but primarily for the security reasons, as all the possible predators can easily learn the whereabouts of a singing animal.

Singing species that live on the trees are in a much more favourable situation, as trees allow different species to live according to their body weight.

So different animals with different body weight live on different " levels " of the tree branches.

For example, a 50 kilo leopard can see and hear the sounds produced by a 15 kilo monkey, but as a lighter monkey can live much higher on the tree branches, it is out of reach of a heavier leopard.

Therefore tree living ( or arboreal ) species feel quite secure to sing or to communicate with a wide range of vocal signals.

On the other hand, all the ground living ( or terrestrial ) animal species, despite the huge weight differences between them ( ranging from rabbits to lions and elephants ) live on the same " ground level ", and maintaining silence is crucially important for them.

Even most of the birds, the most ardent singers, stop singing and producing other sounds when they sit on the ground.

Therefore, predator threat might be a primary reason why tree living species are generally much noisier than ground living species.