Niche construction

In November, a colloquium of the National Academy of Sciences, entitled The Extension of Biology through Culture, celebrated a coming of age of animal social learning research. The meeting, co-organised by ourselves, Marcus Feldman and Francisco Ayala, was a striking testament to how far the study of animal culture has come in recent decades and the truly remarkable set of findings uncovered (footage of several of the talks are available here and here). Speaker after speaker described compelling evidence for social learning being central to the lives of diverse animals, including apes, monkeys, whales and dolphins, birds, fishes, insects and of course, humans. Culture (at least, broadly conceived as the social transmission of learned knowledge) can no longer be construed as the exclusive province of humanity. Social transmission is a major means by which many animals adjust to, and exploit, their environments; a revelation with important implications for evolutionary biology.

As in many reptiles, the sex of leopard geckos is determined not by chromosomes, but by the environment. Hatchlings will develop into either males or females depending on the temperature they experience as incubating eggs. Sex isn’t hard-wired because the key genes involved in gonad differentiation are up- and down-regulated by temperature, so a fairly warm nest will produce mostly males, a cool nest mostly females, and a nest close to the temperature threshold, an evenly mixed brood.