biology zoology insects blog

Can the environment affect an animal’s colour? Of course it can!

Of course !Environment can affect animal’s colour

A few days ago there was on item on the BBC news about a new hair-dye for humans; a dye that apparently changed colour depending on ambient temperature. I immediately thought what’s so special about that? I know many examples in which environmental temperature affects the colour of an animal and chameleons and some Australian desert reptiles came to mind, which are quite dark in the cold of the morning and become increasingly pale as the temperature rises towards noon. And there are amphibians too that respond to temperature changes with colour changes. However, I then realized that the changes I was thinking of depended on hormones that controlled the colour change, but which themselves were affected by the temperature they were operating under. What I needed to look in connection with the hair dye were direct effects of temperature on the pigmentation of an organism, but such effects, especially in combination with humidity levels are also common. —>

Rudimentary Behaviours

Biting Birds and Piloerection

Anybody who knows that the kiwi is foremost and for all a bird (and not a fruit) knows that this New Zealander has no wings – only a few rudimentary bones remain of what were once the winsgs of its ancestors. Whales have no hind limbs, so the entire pubic girdle became vestigial. Certain toes are often superfluous and consequently through the process of selection have diminished in size or disappeared completely as in the horse and other hoofed animals. Teeth, too, as with our so-called wisdom teeth can be vestigial and eye rudiments in cave organism are another example. The anatomical concept of rudimentary organs is therefore easily understood, but we could ask ourselves whether there might not also be something like a rudimentary behaviour or functionally useless action steeped in evolutionary history. Continue reading