In her News Focus story “Predators in the ‘hood” (20 September, p. [1332][1]), V. Morell reported that top predator populations are coming back across much of North America. Meanwhile, predators in Brazil continue to decline. A recent meeting of wildlife experts indicated that the Atlantic rainforest that once stretched along the coast of Brazil and parts of Argentina and Paraguay may soon be the first tropical biome to lose its largest top predator, the jaguar ( Panthera onca ). Researchers estimated fewer than 250 mature jaguars alive in the entire biome, distributed in eight isolated populations ([ 1 ][2]). Even worse, molecular analyses demonstrate that local effective population size (a critical parameter for the maintenance of genetic diversity) is below 50 animals ([ 2 ][3]). ![Figure][4]</img> CREDIT: SANDRA CAVALCANTI Jaguars are persecuted for their potential impact on livestock, and their prey have been overhunted even in large protected areas ([ 3 ][5]). Jaguars provide a crucial service in controlling herbivores (capybaras, deer, and peccaries) and smaller predators (pumas, ocelots, foxes, and racoons), and their overall extinction will likely disrupt predator-prey interactions with unpredictable effects on ecosystem function ([ 4 ][6]). The Atlantic rainforest is a highly fragmented biodiversity hotspot, with less than 12% of the original area left ([ 5 ][7]). Although 24% of the remaining areas are large enough to support jaguars, jaguar populations can be found in only 7% of the rainforest ([ 4 ][6]). Population supplementation and reintroduction programs may provide new hope for jaguars, but uncontrolled hunting of jaguars and their prey is still widespread in most protected areas, threatening the persistence of this important top predator. In the absence of effective protection and management, the fate of the largest predator of the Atlantic forests is bleak. 1. [↵][8] 1. B. M. Beisiegel, 2. D. A. Sana, 3. E. Moraes Jr. , CatNews Special Issue 7, 14 (2012).