JavaScript for PHP Developers

Colophon

The animal on the cover of JavaScript for PHP Developers is an eastern gray squirrel (Sciurus carolinensis), which is a tree squirrel native to the eastern and midwestern United States, and to the southern portions of the eastern provinces of Canada. The genus, Sciurus, is derived from two Greek words: skia, meaning shadow, and oura, meaning tail.

As the name suggests, the eastern gray squirrel has predominantly gray fur, but it can also have a brownish color. It has a white underside and a large bushy tail. It is one of very few mammalian species that can descend a tree head-first; it does this by turning its feet so the claws of its hind paws point backward and can grip the tree bark.

Like many members of the Sciuridae family, the eastern gray squirrel is a scatter-hoarder: it hoards food in numerous small caches for later recovery. Some caches are quite temporary, especially those made near the site of a sudden abundance of food that can be retrieved within hours or days for reburial in a more secure site. Others are more permanent and are not retrieved until months later. Each squirrel is estimated to make several thousand caches each season. The squirrels have very accurate spatial memory for the locations of these caches, and use distant and nearby landmarks to retrieve them.

As in most other mammals, communication among eastern gray squirrel individuals involves both vocalizations and posturing. The species has a quite varied repertoire of vocalizations, including a ...