Sex, Frogs, and Rock & Roll


If frogs were closer to us on the phylogenetic family tree, they might have captured the imagination of evolutionary psychologists and behavioral ecologists more than they have. But the former discipline is still fascinated mostly by chimps and bonobos, apes that differ from us only by about one percent in gene sequences.

In the mid-1990s, researchers in England identified the first gene to be linked to language, strongly suggesting that our linguistic abilities might be at least partially innate—hardwired.

They named this gene FOXP2. For many vertebrates this gene is necessary, during early embryonic development, for the formation of parts of the brain that are associated with language and speech. Across the vertebrate family tree, FOXP2 is highly conserved—it hasn't changed much, albeit it seems to have mutated somewhat among non-human mammals, bats for example.

FOXP2 expression during development has been described in frogs, crocodilians, songbirds, and mice, among others. It is intriguing to contemplate that the development of the Central Nervous System in different vertebrate species is remarkably similar, with conserved expression in the basal ganglia, telencephalon, cerebellum, the hindbrain, tectum, tegmentum, and the thalamus.

In songbirds FoxP2 appears to be essential for learning how to sing. And the basil ganglia, which is necessary for human language, can be traced as far back as amphibians that were similar to frogs.

The basal ganglia works in concert with different regions of the cortex when we walk, talk, or comprehend a sentence. It also provides a foundation for cognitive flexibility and neuroplasticity, allowing a creature to alter their thought process and change plans accordingly when circumstances change suddenly. The study of the FOXP2 regulatory gene, which controls the embryonic development of subcortical systems, should provide keen insights into human evolution.

However far off frogs are to us, there is a connection. So, can the study of frog behavior give us some clues to the evolution of human behavior? In a way, anurans (frogs and toads) may be the first in a long line of rock stars—animals trying to attract a mate by showing off their musical talents. But does a frog really have anything in common with Steven Tyler? Maybe.

Read more »