Livestock production is one of many demands placed on today’s arid rangelands. Therefore, understanding plant and animal biology and their effects on biotic and abiotic landscape components is fundamental if rangelands are to remain ecologically sustainable. One limiting factor to accomplishing positive change on animal dominated landscapes is an incomplete understanding of animal behavior needed to efficiently manipulate and achieve management goals. Livestock differ anatomically and physiologically in their ability to utilize heterogeneous landscapes. The proper stocking of arid landscapes simultaneously with cattle, sheep and goats allows maximum plant biomass to be converted into food and fiber. However, this species mix is not always practical due to predation losses that can occur with small ruminants. Research has clearly demonstrated that by modifying innate animal behaviors, mixed-species groups can be managed successfully using flerds (flocks + herds). Furthermore, today’s technology based on systems such as the global positioning system (GPS) offers exciting mechanisms to tie the spatial and temporal dynamics of plants and animals together to foster proactive management of livestock distribution and animal control in real time. Gene pools within livestock species that have had little influence from human selection such as Criollo cattle offer further exciting possibilities for creating designer animals that match the conditions of arid rangeland landscapes. These and other studies have characterized the Jornada’s animal based research over the past 100 years.