Learning PHP, MySQL, JavaScript, and CSS, 2nd Edition

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The animals on the cover of Learning PHP, MySQL, JavaScript, and CSS are sugar gliders (Petaurus breviceps). Sugar gliders are small, gray-furred creatures that grow to an adult length of six to seven-and-a-half inches. Their tails, which are distinguished by a black tip, are usually as long as their bodies. Membranes extend between their wrists and ankles and provide an aerodynamic surface that helps them glide between trees.

Sugar gliders are native to Australia and Tasmania. They prefer to live in the hollow parts of eucalyptus and other types of large trees with several other adult sugar gliders and their own children.

Though sugar gliders reside in groups and defend their territory together, they don’t always live in harmony. One male will assert his dominance by marking the group’s territory with his saliva and then by marking all group members with a distinctive scent produced from his forehead and chest glands. This ensures that members of the group will know when an outsider approaches; group members will fight off any sugar glider not bearing their scent. However, a sugar glider group will welcome and mark an outsider if one of their adult males dies (the group will typically replace a deceased adult female with their one of their own female offspring).

Sugar gliders make popular pets because of their inquisitive, playful natures, and because many think they are cute. But there are disadvantages to keeping sugar gliders as pets: as they are exotic animals, sugar ...