Given the inaccessibility of much of the species range, particularly the central Amazon, estimating jaguar numbers is difficult. Researchers typically focus on particular bioregions, thus species-wide analysis is scant. In 1991, 600-1,000 (the highest total) were estimated to be living in Belize. A year earlier, 125-180 jaguars were estimated to be living in Mexicos 4,000-km2 (2400-mi2) Calakmul Biosphere Reserve, with another 350 in the state of Chiapas. The adjoining Maya Biosphere Reserve in Guatemala, with an area measuring 15,000 km2 (9,000 mi2), may have 465-550 animals. Work employing Global Positioning System telemetry in 2003 and 2004 found densities of only six to seven jaguars per 100 km2 in the critical Pantanal region, compared with 10 to 11 using traditional methods; this suggests the widely used sampling methods may inflate the actual numbers of cats.. How many more km2 is the Maya Biosphere Reserve in Guatemala than the Mexicos Calakmul Biosphere Reserve?