In settler colonialism, “settler” populations arrive and establish themselves in new lands (Barnd, 2017). Simpson (2017) highlights “land” as central to settler colonialism: “colonizers want land” and therefore “everything else, whether it is legal or policy or economic or social,” is part of settler colonialism “machinery” (p.15). Settler populations implement “a fundamental transformation in the demographics, cultures, and physical landscape of colonized lands,” with the aim “to solidify territorial claims” (Barnd, 2017, p.9). This involves “the biopolitical and geopolitical management of people, land, flora and fauna,” using certain “modes of control,” including imprisonment, boundaries, and property regimes (Tuck and Yang, 2012, p.4-5). Borders, walls, and militarization are key components of white settler colonialism.

In the United States, attempts at wildlife eradication – particularly large carnivores and buffalo² – are rooted in historic and contemporary processes of white settler colonialism (Schneider, 2022). In the dispossession of Indigenous lands, particular species have been viewed as obstacles to “civilization” and settler land-uses, including homesteading, agriculture, and livestock rearing (Mamers, 2020). The mass killing of buffalo was a form of colonial control and spiritual genocide for tribal nations (Mamers, 2020; Schneider, 2022). Conservation and creation of “livable” settler conditions meant “extermination” and “control,” both of animals and Indigenous peoples, a process which is ongoing though challenged by Indigenous resistance (Robinson, 2005; Simonian, 1995).

Wolves were a main target of white settler colonialism in the U.S. Predating the Declaration of Independence, the first government-to-citizen subsidies were bounties paid for wolf kills in New England (Robinson, 2005, p.32). In 1869, the Colorado legislature enacted wolf bounties, and other western states soon followed (Robinson, 2005, p.31). Western wolves were swiftly exterminated following these legislative changes and, in 1926, Yellowstone Park rangers killed the last American wolf, save for a small population that traversed the U.S.-Canada border (Ripple and Larsen, 2000). Shortly thereafter, in 1932, the US Senate Committee on Agriculture and Forestry supported additional funding for eliminating predators, saying: “the wolf and the coyote is not satisfied after he gets a living … they kill merely for the love of killing…” (U.S. Senate, 1932, p.25).

Despite near extermination of predators by the early-1900s, settlers continued claims that predator kills of livestock resulted in significant income losses. In 1930 Arizona, income losses by predatory animals were calculated to be $623,500 (U.S. Senate, 1932, p.162), despite that wolves, mountains lions, and coyotes had been largely eradicated (Robinson, 2005). Livestock losses to predators were very likely inflated by settlers (Robinson, 2005).

Recent anti-predator legislation demonstrates the extent to which settler discourses and attitudes are alive and well in wildlife management today (Oppie, 2021; Brasch, 2023). A 2021 law allows Idaho hunters to kill 90% of the state’s wolf population, citing wolves’ impacts on livestock and game species (e.g. deer, elk). ³ However, only 130 cattle and sheep – out of more than 2.7 million in the state – “were confirmed or probable(y)” killed by wolves in 2019-2020, and Idaho’s elk population is at “an all-time high” (Oppie, 2021). Indeed, white settler colonial perceptions of wildlife have long been ingrained in American politics and environmental practice.

The U.S.-Mexico borderlands of Arizona are the ancestral homelands of numerous O’odham, Apache, and Yavapai nations. Starting in the early-1600s, the Spanish utilized violence, missions, and trade to control the region (Austin, 1991; Wright and Hopkins, 2016). After Mexican independence from Spain in the early 19^th century, Indigenous peoples were considered Mexican citizens but were rarely informed of rights. Tribal nations like the Tohono O’odham continued to lose land to cattle ranches despite Mexican citizenship (Austin, 1991, p.99).

The Treaty of Guadalupe (1848) and Gadsden Purchase (1853) created the modern political border through transfer of substantial Mexican territories to the U.S (Austin, 1991; Molina, 2021). This led to increased settlement of land on the U.S. side of the border, and further dispossession from Indigenous nations (Wright and Hopkins, 2016; Human Rights Clinic et al., 2014). The U.S. government waited over a decade after the influx of Anglo settlers to reserve land for Indigenous communities, and reservations excluded core resources and settlements. For instance, in creation of the Gila River Indian Reservation and other O’odham reservations, tribal settlements, pastureland, mesquite grounds, and water sources were excluded (Wright and Hopkins, 2016). Water use by settler towns and farms led to catastrophic impacts for Indigenous communities, including recurring famines and poverty (Wright and Hopkins, 2016).

The modern political border between the U.S. and Mexico also split Indigenous nations’ populations and territories (Austin, 1991). While tribal members in both U.S. and Mexican Tohono O’odham territories have sought to retain identity as a single tribe, it has been increasingly difficult with border militarization in the 20^th century (Molina, 2021). ⁴ Tohono O’odham are also targeted, detained, and deported by Customs and Border Patrol (CBP), even when carrying identification on tribal land (Austin, 1991, p.101; Kowalski, 2017, p.646).

Other borderland tribes have also been impacted. A 1906 U.S.-Mexico treaty prohibits border wall in the Rio Grande River, so wall has been constructed a mile north of the border in Texas, significantly impacting wildlife and peoples, such as Lipan Apache, who can no longer access crucial river landscapes (Kowalski, 2017, 653; Human Rights Clinic et al, 2014).

Scholars have demonstrated how the eradication of wildlife and Indigenous people are co-constituted (Barnd, 2017; Global Federation of Animal Sanctuaries (GFAS), 2018; Mamers, 2020; Schneider, 2022). White settler colonialism has had major impacts for people and animals in the borderlands. These process, moreover, are not rooted in a colonial past, but ongoing, and constituted through current state-society interactions and political economic arrangements (de Leon, 2015; Tuck and Yang, 2012). The review of border and immigration policies below shows the extent to which ecology, race, and politics continue to be important factors that shape and transform the borderlands.

The jaguar has long played major roles in stories of many borderland tribes, including Yaqui, Hualapai, Yavapai, Tohono O’odham, Dine, and Zuni tribes (Molina, 2021; Pavlik, 2003). In February 2009, a male jaguar named Macho B was snared, sedated, and tagged with a radio collar by a jaguar researcher. ⁵ Twelve days later Macho B was euthanized due to injuries sustained in the capture. The Tohono O’odham tribe spoke against the animal’s capture with an elder stating, “Whatever valuable data might be acquired, handling a jaguar in such a manner completely violates the traditional tribal view as to how we should deal with a fellow animal person” (Pavlik, 2003, p.171).

Yet, jaguars, seen as a threat to livestock, have long been a source of intrigue and obsession for white settlers. In 1930, the U.S. Secretary of Agriculture enacted a long-term “cooperative program for the eradication, suppression, or bringing under control of predatory and other wild animals injurious to agriculture” (U.S. Senate, 1932). The program included a provision that was already Arizona policy, “All Lobo wolves and jaguars will be taken as fast as they enter this State from Mexico and New Mexico, as 100 per cent of them live on livestock and game” (U.S. Senate, 1932, p.24). ⁶

Roughly 80 jaguars were recorded in Arizona between 1858 and 2018, at least 57 of which were killed between 1858 and 1986 (Babb et al., 2022). However, this number is surprisingly low compared to other predators exterminated in the region. Jaguars’ relative scarcity in 1800s historical records, particularly compared to wolves or mountain lions, indicates a lower population than expected given habitat conditions (Davis, 1982; Robinson et al., 2005). This is likely because jaguars were targets of colonial policies long before U.S. control of the Southwest (Robinson et al., 2005).

In 1617 – long before 18^th century wolf bounties in New England – Spain’s King Felipe II ordered the killing of predators in “New Spain,” including modern day Arizona and New Mexico (Sundberg, 2011; Simonian, 1995). Large cats were particularly vilified by the Spanish, who introduced the practice of using dogs to chase large cats into trees, where they were shot (Simonian, 1995, p.36). By the time the U.S. gained control of the region in the 1840s, jaguar numbers reflected Spanish bounties and extermination practices (Robinson et al., 2005).

In a government-commissioned 1859 survey of the U.S.-Mexico border, Baird (1859) speculated that while jaguars were still seen in Texas, they had been killed-off in other areas and had “a minor importance when compared with the puma ⁷ “ in terms of threat to livestock (p.7). In northern Mexico he reported:

By the mid -1800s, according to Baird, jaguar extermination was common practice among ranchers in northern Mexico.

White settler colonial attitudes toward jaguars transcended the border, particularly among ranchers who viewed the animals as a major threat to livestock. Today, the most serious threat to jaguars globally is extermination by humans, largely pro-active and retaliatory killing from perceived and actual conflict with humans and livestock (Connolly and Nelson, 2023; Jędrzejewski et al., 2017; Knox et al., 2019). ⁹

While there is recent evidence of Mexican ranchers poisoning jaguars (Arratibel, 2022; Kryt, 2019), it is important not to essentialize ranchers and other rural land-users as anti-predator and anti-jaguar. Several successful conservation collaborations exist wherein environmental organizations, ranchers, and others work to conserve habitat corridors and animals. In Sonora, Mexico, Northern Jaguar Project works with ranchers, rural community members, conservationists, and other stakeholders to conserve jaguar habitat and monitor animals, including through collaborative installation and monitoring of motion-triggered cameras on private land. Connolly and Nelson (2023, p.10) found that while some American ranchers feel jaguars “have not ever and should not now live in the United States,” others value biodiversity and identify a need to collaborate with various stakeholders to maintain open space for both ranching and jaguars.

Between 1996, when Border King was seen in southern Arizona, and 2023, at least seven male jaguars have been captured on camera traps in Arizona, presumably dispersing across the border from northern Mexico (Connolly and Nelson, 2023), where the nearest breeding population exists. Most recently, a previously unidentified jaguar was observed in late-December 2023 in southern Arizona (Center for Biological Diversity, 2024). Jaguars have large ranges and space requirements; home ranges for adult males can exceed 230 km² (Morato et al., 2016; Thornton et al, 2016). ¹⁰ Female jaguars disperse shorter distances than males (Sadowski-Smith, 2013; Povilitis, 2015). Landau et al. (2022) recently used presence-only and occupancy data to estimate that there is approximately 25,463 km² of suitable jaguar habitat in their study area, which included northern Mexico.

Sonora, the Mexican state that borders Arizona, contains an estimated 80-120 jaguars in the northern part of the state (Northern Jaguar Project, 2023). While several female jaguars and cubs have been spotted in northern Sonora, no female jaguar has been identified in the United States since the last female was shot in Arizona’s White Mountains in 1963 (Brown and Lopez, 2000). Population health thus relies on the transnational movement of jaguars in core habitat and corridors (Culver, 2016).

19^th century Mexican laws, along with habitat conditions, could explain why jaguar populations have been more stable in Mexico than the United States (Weber, 1982; Ceballos et al., 2021). In 1824, following Mexico’s independence from Spain and due to increased U.S. settlers in the borderlands, the Mexican government made it illegal for non-Mexicans to hunt or trap “fur-bearing animals,” including jaguars (Simonian, 1995, p.50). Furthermore, while the U.S. was experiencing a sense of “inexhaustible” resources in the 1880s, Mexico – conscious of water catchment and supply – implemented laws to preserve forests, which often coincide with jaguar habitat (Simonian, 1995, p.53). Mexico also has more land suited for jaguar habitat compared to the U.S (Ceballos et al., 2021). Policies to protect jaguars in Mexico have focused on local and regional conservation, along with surveying and monitoring. A recent survey found the Mexican jaguar population increased from 4,000 in 2010 to 4,800 in 2018 (Ceballos et al., 2021; also Rodriguez-Soto et al., 2013). In the borderlands, however, jaguar population health is also tied to U.S. policies and land-use practices.

As previously mentioned, settler colonialism, including the quest to control and militarize land, have long been detrimental to wildlife, particularly apex predators like jaguars. Ecological knowledge of trophic cascades has demonstrated how vital apex predators are to ecological systems. When large predators were removed from the western U.S. in the 1900s, increased prey species damaged plant communities, leading to erosion of riverbanks and floodplains (Beschta and Ripple, 2012; Ripple and Larsen, 2000). Jaguars, with large ranges and apex predator roles, also act as an umbrella species, and help maintain ecological processes such as controlling prey species and carcass provision for scavengers and other organisms (Connolly and Nelson, 2023). Ecologists have recently called for “rewilding” practices vis-à-vis jaguar reintroduction that are “essential to species conservation, ecosystem restoration, and rewilding” (Sanderson et al., 2022, p.2). Conservation and rewilding efforts are particularly complicated in the U.S.-Mexico borderlands which have become increasingly militarized in recent years.

In the mid to late 20^th century, the political division between the U.S. and Mexico “shifted from a border, a zone of gradual transition, to a boundary, a stark line of demarcation” (Nevins, 2010, p.147). Table 1 highlights important U.S. policies on border militarization and barrier construction. Funding for border militarization increased substantially during the 1990s “prevention through deterrence” (PTD) strategies, directed at barrier infrastructure, including fence and vehicle barriers, as well as video surveillance, vehicles, and personnel. A particularly pivotal year in border militarization was 1994, when historic urban crossing points were shut down and the U.S. government intentionally pushed people into harsh environments which resulted in migrant deaths (Andreas, 2000; Nevins, 2010; Sundberg, 2011; de Leon, 2015).

The practice of intentionally driving people into harsh and dangerous environments became known as the “funnel effect” (Rubio-Goldsmith et al., 2006; Soto, 2018). U.S. immigration officials used natural terrain – rivers, desert, mountains – as “deterrents to illegal entry” (U.S. GAO, 2017; U.S. Immigration and Naturalization Service (INS), 1996, p.24). Policy makers, moreover, anticipated Border Patrol agents would achieve a “tactical advantage” in apprehending people who attempted to cross through remote and difficult terrain (Sundberg, 2011, p.323; U.S. INS, 1996, p.3). In the 1990s, migrant deaths began to soar due to PTD interventions and policies (Cornelius, 2001; Michalowski, 2007). Between 1996 and 2000, migrant deaths in the borderlands increased 474%, including a 1,181% increase in deaths for people crossing into Arizona (Cornelius, 2001). de Leon (2015, p.4) argues the Border Patrol “disguises the impact of its current enforcement policy by mobilizing a combination of sterilized discourse, redirected blame, and ‘natural’ environmental processes that erase evidence of what happens in the most remote parts of southern Arizona.” Border policy shifts in the 1990s gave rise to human smuggling networks and reflect ongoing practices of white settler colonialism wherein settlers’ economic interests and control of land trump human life and rights (de Leon, 2015).

Operation Gatekeeper and other “prevention through deterrence” strategies also coincided with the North American Free Trade Agreement (NAFTA) of 1994 and the subsequent flooding of Mexican markets with U.S. corn and other agricultural products, which policy makers knew would hit rural farmers hard and increase undocumented migration (Ackerman, 2011; de Janvry et al., 1995). In other words, while 1990s neoliberal reforms created liberalized environments for the production and movement of commodities and capital, border militarization aimed to restrict the movement of people and labor.

The terrorist attacks of September 11^th (hereafter 9/11) radically transformed border policies. Laws focusing on terrorism and security after 9/11 significantly extended the reach of the U.S. federal government along the southern border, and consolidated power under the U.S. Department of Homeland Security (DHS). In 2005, as part of the Real ID Act, DHS was allowed to “waive all laws as necessary to ensure expeditious construction of certain barriers and roads at the U.S. border” (H.R.418 – 109th Congress, 2005-2006, p.1). A year later, the Secure Fence Act (2006) authorized DHS’s “operational control” of the border through numerous tactics, including building roads (Painter and Singer, 2020, p.3). The waivers allowed for immediate road building, use of off-road vehicles, and setting up camps in wildlife refuges and other state and federal lands (Sundberg, 2011). DHS rapidly utilized these new powers, and in less than a year, waived many long-standing federal regulations (e.g. Endangered Species Act) to build border fence (Nuñez-Neto and Garcia, 2007).

Border barrier expansion continued after 9/11, during both democratic and republican administrations. Under the Obama administration, over 209 km of border barrier was built, almost all during his first year in office (Montoya Bryan, 2019). Funding for this construction was largely approved in the previous administration, and border barrier construction was essentially halted in 2010 (Painter and Singer, 2020).

From 2016-2020 President Trump redefined border security along the U.S.- Mexico border (Painter and Singer, 2020). The DHS under Trump used the Illegal Immigration Reform and Immigrant Responsibility Act of 1996 (IIRIRA) and Real ID Act to waive regulations. ¹¹ As previously mentioned, these actions followed a campaign that vilified Mexican migrants and promised to “build the wall” to curb migration (Finley and Esposito, 2020; Horton, 2021). Trump’s rhetoric framed refugees and immigrants as cop murderers and included an ad so extreme that even Fox News refused to air it (Grynbaum and Chokshi, 2018). The Trump administration oversaw reinforcement of 700 km of existing border fence with taller, thicker barriers, and built an additional 120 km of fence (Giles, 2021). For our study area, we mapped these shifts in border barriers between 2005 and 2021, and examined the relationship between border barrier and suitable jaguar habitat.

Borders and militarized zones can have contradictory implications for wildlife. While border barriers can limit animal movement, they can also limit human movement and development, thereby providing wildlife protection from humans (Trouwborst et al., 2016). Borderlands also serve as refuge for animals hunted and exterminated in interiors of countries, for instance wolves along the U.S.-Canadian border and cranes in the Korean Demilitarized Zone (Ripple and Larsen, 2000; Kim, 2013). In Kashmir, by contrast, fencing and conflict have pushed leopards into urban areas and in direct conflict with humans (Habib et al., 2015).

Trouwborst et al. (2016) note that the type of barrier or militarized zone hugely impacts wildlife. Fences and walls, for instance, are designed to be impenetrable and thus directly curtail animals’ mobility, fragment populations and cause direct mortality (Trouwborst et al., 2016). Fences and walls limit movement and thereby reduce access to water, food, and mates for wide-ranging and migratory species, including those with fragmented habitats (Liu et al., 2020). Large carnivores and herbivores are particularly vulnerable to the deleterious impacts of fences and walls (Linnell et al., 2016).

In the U.S.-Mexico borderlands, wall construction has directly reduced the area, quality, and connectivity of available habitat by physically limiting wildlife movement, and dispersal of species that cannot climb or move through existing walls (Chambers et al., 2022; Flesch et al., 2010; Peters et al., 2018). Wall and fence infrastructure are expected to divert dispersing jaguars and have already been shown to divert movement of other species in the region (e.g. mountain lion and coati) (Chambers et al., 2022; McCallum et al., 2014).

Furthermore, Kamath and Wesner (2020) historicize and contextualize the concept of territoriality in biology, reminding us that animals do not always behave how humans predict. The authors urge scholars to demonstrate the function of animal behaviors and specific relationships among individuals rather than assuming particular responses or dynamics are at play. This is particularly important with respect to our habitat model, and our results on what percentage of potential habitat has been cut off by border barrier.

We mapped jaguar observations for two temporal periods in the American southwest ( Figure 1 ). ¹² Figure 1 maps jaguar observations between 1840-1910, based on historical documents. This is also a time that corresponds with the predator eradication practices described above. Figure 1 also maps jaguar sightings between 1996 and December 2023. While suitable jaguar habitat may include historic ranges into northern areas of the American southwest (e.g. southern Colorado), as indicated in Figure 1 , jaguar observations since 1996 remain within 100 km of the U.S.-Mexico border ( Figure 1 ).

Our study area thus extends from Baboquivari Peak Wilderness in Arizona to the southeast corner of Hidalgo County, New Mexico. This area was selected based on recent documentation of jaguars in the area (Culver, 2016; Hatten et al., 2005) ( Figure 1 ). The North-South dimensions of the project were less important, as this research specifically was meant to measure habitat on the border. ¹³ The selected study area also largely corresponds with other studies that have examined contemporary jaguar habitat in the U.S. (e.g. Chambers et al., 2022; Culver, 2016; USFWS, 2014).

Our study area contains a variety of elevations and vegetation zones, largely due to the Madrean Sky Islands, which are 55 mountains covered with pine and oak trees, at the highest elevations, and separated by desert and/or grassland topographies (Connolly and Nelson, 2023). A sky island often covers six different biomes, from the low elevation scrubland, to oak, and then high elevation fir forests (Connolly and Nelson, 2023). The average annual rainfall for our study area is about 400 mm, the majority occurring from July through September. ¹⁴ The sky islands exist across southern Arizona, southwestern New Mexico, and the Sonora and Chihuahuan Deserts in Mexico, and are important habitat and corridors for jaguars and other endangered species (Chambers et al., 2022).

A 2014 U.S. Fish and Wildlife Service (USFWS) report identified important factors for suitable jaguar habitat, including availability of prey, access to water, cover and terrain, and density of nearby human populations (USFWS, 2014; Chambers et al., 2022). Higher levels of canopy cover, along with desert springs and narrow canyons are ideal habitat for jaguars, and jaguars detected in grasslands were usually in rocky canyons (Chambers et al., 2022; Culver, 2016).

While this study largely draws from the geospatial methods described below, we also found and reviewed legal and historic documents from various entities including the U.S. military, Department of Defense, and environmental organizations.

Our first objective was to model suitable jaguar habitat. We drew from ecological studies to identify important jaguar habitat variables (Culver, 2016; Hatten et al, 2005; Sanderson et al., 2022) ( Table 2 ). Historic and recent jaguar observations in our study area demonstrate jaguars remain 1-10 kilometers (about 6.21 mi) from water sites and generally prefer forested and grassland communities. As solitary animals, jaguars generally avoid human development and major roads by 8-9 kilometers. While jaguars have been recorded at multiple elevations, they generally prefer regions between 1,200-1,800 meters in elevation (Culver, 2016; Hatten et al., 2005). Using presence-only and occupancy data, Landau et al. (2022) suggested high terrain ruggedness and presence of riparian vegetation were most strongly related to habitat use by jaguars.

For each variable identified in ecological studies as important for determining jaguar habitat, we obtained publicly available data ( Table 3 ) and performed a spatial analysis using ArcGIS Pro version 2.8.0. All non-raster data were converted to raster format and set to a 30-meter pixel resolution. ¹⁵ An overlay analysis was then performed using ArcGIS Pro to designate areas as habitable or uninhabitable (Esri, 2023b). The formula H = v1 * v2 * v3 * v4 * v5 * v6 was applied to each cell. In this formula, every habitat variable (v) from Table 2 was assigned a value of 1 or 0 depending on whether it met the standard of jaguar habitability (1) or not (0). Jaguar habitability for each cell was determined by the outcome of H, so that only cells meeting all requirements of variables could be considered suitable habitat.

Our second objective was to map expansion of border barriers between 2005 and 2021. Table 3 highlights data used to map barriers. ¹⁶ To analyze barrier expansion, three years were selected: 2005, 2015, and 2021. These years were selected as they capture status of the border before and after the 2006 Secure Fence Act, and border barrier expansion under the Trump administration between 2017 and 2021. Preliminary review of existing literature and policy documents indicated these years and policy shifts were pivotal for border barrier changes ( Table 1 ).

Border barriers were visualized using polyline shapefiles for the three years. ¹⁷ Information on areas covered by polylines and attributes was derived from pre-existing spatial data (U.S. Immigration and Customs Enforcement, 2013; Wildlands Network, 2021) that required georeferencing ( Table 3 ). These data sources were compared to polylines digitized using aerial imagery. Comparing maps and polyline vector data to digitized polylines allowed for better accuracy when georeferencing and provided insight on gaps in border barrier.

Border barrier was visualized in two different ways: temporal change and wall type. Visualization for both was fulfilled by differentiating attribute fields for the polylines. Polylines for all years were split into separate segments that deciphered temporal change for the following categories: ¹⁸ 1) new footprint (new footprint of border barriers; no barrier existed during previous time period); 2) replacement (prior time period showed barrier existed but was replaced); 3) no change (barrier did not experience change between the two periods).

The second visualization was intended to display the different types of barriers identified during each year. Data provided from Wildlands Network provided descriptions of barrier type by location (Wildlands Network, 2021). Elaborations on definitions of barrier were provided by the Department of Homeland Security (U.S. DHS, 2021a, U.S. Department of Homeland Security, 2016b). From these definitions, we created attribute fields in border barrier polyline data that separated “vehicle barriers” from “walls.”

Our analysis revealed suitable jaguar habitat in our study area in 2021 was 11,385 km² ( Figure 2 ). The amount of jaguar habitat adjacent to the border in our study area is 155 kilometers, though it is important to note that this is not a contiguous distance. Figure 2 thus identifies areas that would likely serve as points of core habitat and connectivity with Mexico.

We also understand that jaguar and other wildlife movement and behaviors may not overlap perfectly with these areas (also Landy et al., 2018; Grigione and Mrykalo, 2004). For instance, while we mapped jaguar habitat to not exist within 1000 meters of human development based on Culver (2016) conditions for jaguars, research has shown border barriers and militarization have pushed large carnivores into cities and areas of human development (Pahalwan, 2007; Habib et al., 2015). Suitable habitat conditions must thus be taken with a grain of salt, and researchers should be open to surprises and unpredictability in animal behavior, perhaps especially in areas where habitat and corridors have been cut off quickly by human-constructed barriers (Kamath and Wesner, 2020; Wilkinson et al., 2021). Border barriers, and impenetrable wall in particular, may profoundly reshape jaguar geographies and human-wildlife interactions.

We analyzed the expansion of border barrier between 2005-2015 and 2016-2021. Our results are visualized in Figures 2 – 4 and discussed below.

Within the study area, the spatial footprint of all border barrier was 303 km by 2021. In other words, 82.7% of the border (for our entire study area) had barrier by 2021 ( Figures 2 – 4 ). ²² Figure 3 visualizes the growth and changing type of border barrier between 2005 and 2021. Of this 303 km in 2021, 67% was wall and 33% was vehicle barrier ( Figures 3 , 4 ). Of the suitable jaguar habitat that touched the border in the study area (155 km), 86% (or 133 km) had been cut off by border barrier by 2021 ( Figure 2 ). Of this barricaded distance, 76.74% was wall and only 23.26% remained vehicle barrier which, again, jaguars and other wildlife are more likely to cross ( Figures 3 , 5 , 6 ).

The border wall has significantly degraded landscape connectivity. The physical barrier disrupts migration and dispersal routes, preventing wildlife from accessing critical resources including food, water, and mates (Peters et al., 2018). It is increasingly difficult for large endangered animals such as the jaguar, Mexican gray wolf, and Sonoran pronghorn to disperse across the border, fragmenting already at-risk populations (Connolly and Nelson, 2023; Peters et al., 2018). Nearly 100 km of pedestrian fence south of Tombstone, Arizona, for instance, bisects an otherwise probable movement corridor for jaguars, preventing dispersal through this region (Landau, 2020, p.40).

Chambers et al. (2022) predicted border wall construction would result in an increase in the amount of energy jaguars would expend while looking for routes around the wall. Changing access to prey and increased energy expenditures may further threaten jaguars’ “reproductive success and survival” (Chambers et al., 2022, p.7). Since all known breeding populations of jaguars are south of the border (Culver, 2016), walling habitat corridors has signficant implications for jaguar survival in the U.S.

Jaguars, moreover, are not only impacted by physical barriers, but by the overall militarization of the region. Jaguars prefer secluded areas and are deterred just by the presence of roads, checkpoints, and lights (Bleir, 2020). Border construction has also dammed up streams and drainages, removing critical water resources that jaguars and other animals rely upon in a desert environment (Wildlands Network, 2021).