Discovered by 16th century sailors, the news of Galapagos tortoises soon brought ships crossing the southern Pacific Ocean to the Galapagos Islands where the crews gathered tortoises for their journey. Tortoises were stored alive in the ships' holds for up to a year as a valuable source of fresh meat. Along with harvesting thousands of the creatures, the ships left behind black rats that sought out and ate tortoise eggs and infants. Eventually a colony of island settlers provided additional dangers to the tortoises in the form of imported domestic animals that also ate eggs and young, as well as grazing on plants the tortoises needed and trampling their nests. Although recent intervention has saved most of the Galapagos tortoise species from disappearing, extinctions of many species, including mammoths, passenger pigeons, bisons, and dodo birds, are directly linked to a human cause. Explanations for other extinctions, such as that of the dinosaurs, provoke speculation. Currently, many people and organizations are working to preserve threatened animals, but the rate of disappearance due to oil spills, nuclear wastes, pesticide use, rain forest and wetland destructions, and acid rain continues to escalate. (Ages 8-11)