Desert Canyon Research Articles

Could the Ancestral Puebloans of Chaco Canyon, New Mexico, Have Depended on a Groundwater Ecosystem?

A thousand years ago, a population of Ancestral Puebloans occupied a high desert canyon in northwestern New Mexico, USA, where precipitation was limited and surface water scarce. Geological conditions, however, seem favorable for the production of a large Hypocrene springs system near the south canyon walls sufficient to have produced a groundwater ecosystem favorable for agriculture, tree growth, and human occupancy. A human-induced ecological impact is suggested as contributing to the dewatering of the springs, eventually reducing local agricultural production and, presumably, the suitability of Chaco Canyon for human occupancy.

New species in the Sitalcina sura species group (Opiliones, Laniatores, Phalangodidae), with evidence for a biogeographic link between California desert canyons and Arizona sky islands

The western United States is home to numerous narrowly endemic harvestman taxa (Arachnida, Opiliones), including members of the genus Sitalcina Banks, 1911. Sitalcina is comprised of three species groups, including the monospecific Sitalcina californica and Sitalcina lobata groups, and the Sitalcina sura group with eight described species. All species in the Sitalcina sura group have very small geographic distributions, with group members distributed like disjunct “beads on a string” from Monterey south to southern California and southeast to the sky-island mountain ranges of southern Arizona. Here, molecular phylogenetic and species delimitation analyses were conducted for all described species in the Sitalcina sura group, plus several newly discovered populations. Species trees were reconstructed using multispecies coalescent methods implemented in *BEAST, and species delimitation was accomplished using Bayes Factor Delimitation (BFD). Based on quantitative species delimitation results supported by consideration of morphological characters, two new species (Sitalcina oasiensis sp. n., Sitalcina ubicki sp. n.) are described. We also provide a description of the previously unknown male of Sitalcina borregoensis Briggs, 1968. Molecular phylogenetic evidence strongly supports distinctive desert versus coastal clades, with desert canyon taxa from southern California more closely related to Arizona taxa than to geographically proximate California coastal taxa. We hypothesize that southern ancestry and plate tectonics have played a role in the diversification history of this animal lineage, similar to sclerophyllous plant taxa of the Madro-Tertiary Geoflora. Molecular clock analyses for the Sitalcina sura group are generally consistent with these hypotheses. We also propose that additional Sitalcina species await discovery in the desert canyons of southern California and northern Baja, and the mountains of northwestern mainland Mexico.

Roost and Forage Site Fidelity of Western Small-Footed Myotis (Myotis ciliolabrum) in an Oregon Desert Canyon

We describe the roosting and foraging behavior patterns of western small-footed myotis (Myotis ciliolabrum) observed during a vertebrate inventory of the John Day Fossil Beds National Monument in north central Oregon. We used radiotelemetry to track 9 adult females, including 3 lactating and 6 postlactating bats, during July-September 2003. We found that these bats showed considerable fidelity to a common foraging area at the confluence of the John Day River and a tributary creek along which bats commuted and roosted. Individual bats did not roost together, but each showed high fidelity to local clusters of rock outcrops in small side canyons along the tributary. Roosts were not found in large, exposed cliff faces, despite the availability of such features. Rather, radio-tagged bats roosted in smaller outcrops that averaged 4.5 m in height. Bats commuted up to 12 km from roosts in the tributary canyon to the common foraging site at the river confluence and remained on the wing to forage for up to 4 h before returning to day roosts. No radio-tagged bats were observed using night roosts, even after pups were weaned. Our study provides a description of roosting, commuting, and foraging activity, as well as habitat use, of western small-footed myotis. This information provides a nuanced perspective on the ecology of canyon-dwelling bats in the region. Such perspective could be useful for conservation and habitat management.

Nevermore the Reverberations: (for Alan Dawley)

Nevermore the Reverberations (for Alan Dawley) Janet Gray (bio) During the summer of 1988, camped along the Colorado River in a blazing desert canyon on my way to graduate school, I listened to actor Dan O'Herlihy on tape reading Whitman's "Out of the Cradle Endlessly Rocking," in which the poet remembers himself as a boy hearing a male mockingbird call to its lost mate. In the following passage, I heard Poe. . . . never more shall I cease perpetuating you,Never more shall I escape, never more the reverberations,Never more the cries of unsatisfied love be absent from me . . . . (ll. 151-53) Brit, an Irish setter, died of heatstroke, and the 1966 Barracuda's engine blew along the way, but once I reached a research library, I scoured biographies and notebooks and satisfied myself that Poe was there. For the hundred-fiftieth anniversary of the first Leaves of Grass, although my curiosities had long since turned elsewhere, I revived this project and found that a succession of critics had noticed "The Raven" in "Out of the Cradle." Each critic made more or less of the echoes.1 Milton Hindus found, as I did, that "the longer we consider the matter, the more parallels between the two celebrated poems emerge," but he resisted seeing the parallels as intentional on Whitman's part because Whitman told himself not to refer to other poets or poems (5). Ned Davison compared and contrasted the two poems and concluded that, whether consciously or not, Whitman "derived artistic stimulation" from Poe (6). Joseph M. De Falco argued that Whitman's extensive revisions of the poem for the 1867 edition of Leaves of Grass demonstrate Whitman's struggle [End Page 27] against the cultural morbidity of which, to him, Poe was representative (22-27). M. Jimmie Killingsworth claimed that, with these revisions, Whitman tried to "obscure" his allusions to "The Raven" (92). Betsy Erkkila noticed that the mockingbird's loss changes him from a joyous, communal singer to something "closer to the neurosis and solipsism" of a Poe character, a change that Whitman's poetic voice underwent in the years leading up to the Civil War. Kenneth M. Price suggested the echoes of Poe represent Whitman's effort to use Poe's notoriety to attract attention to his own work and benefit from the contrast between his own healthfulness and Poe's morbidity (65-66). Daneen Wardrop highlighted the successful embrace of the oedipal loss that occasions the birth of language in Whitman's poem in contrast to paralytic failure in Poe's (88-89). These commentaries emerge from different phases of ferment in literary theory and intervention in the American canon, but they all tend to use the similarities between the poems to reinstate differences between the poets. None challenges what we're already supposed to know: "Out of the Cradle" is a better poem than "The Raven," and Whitman is the better poet—and better for us. Why connections between the two poems matter remained for me an open question. In the canyon, finding Poe in "Out of the Cradle" mattered to me because "The Raven" was the stuff of my childhood and I didn't get Whitman. I'd started a journey, and to finish it, I needed to get him. "Nevermore" was an entry. My initial library quest left me mystified about the differences between the two poems—about how literary critics and historians could hold them apart. I had the uneasy feeling that when they were separated and ranked, something that matters gets left out. What if one were to view what we are already supposed to know with suspicion and pursue the poems' common ground? During formative decades in the making of American literary culture, both of these American poets chose imitative birds that somehow speak English for their entries in the Romantic bird lyric—think of Shelley's "To a Skylark" or Keats's "Ode to a Nightingale."2 That's interesting. Neither Poe nor Whitman relies on the supposedly "truthful relation between word and world" (Diamond 363); both supplement mimesis with mimicry. The raven delivers English from a vague elsewhere, stripped of source and context, so that it...

Fronteras Imaginarias: Theorizing Fronterizidad in the Simulated Illegal Border Crossings of El Alberto, Mexico

Spring 2011 23 Fronteras Imaginarias: Theorizing Fronterizidad in the Simulated Illegal Border Crossings of El Alberto, Mexico Natalie Alvarez1 “Oye, Gloria, aguantaras hasta California?” (“Hey, Gloria, can you make it to California?”). I was expecting the significance of this tourist’s question to be diffused by nervous laughter, as we crouched, huddled along a dusty path in amongst brush in the dead of night with little moonlight and only our coyote to guide us. The question, instead, was met with awkward silence as we tried to catch our breath. Two hours into this night trek through the desert canyon of El Alberto, Mexico in the heart of the Valle del Mezquital—with our field of vision limited to the person next to us, but imaginatively reaching all the way to the border some seven hundred miles north of the site of this fictional border crossing—the prospect of “making it” “for real” is, in fact, unimaginable. This question, “Can you make it to California?” uttered in the context of this simulated border crossing was an invitation—or perhaps a reminder—for all of us tourists huddled there to immerse ourselves “in the role” of illegal migrant and to try to amplify in our imaginative vistas—by hours, by degrees of hunger, thirst and fatigue, by levels of fear, injury, and threat—this mere fragment of an experience into the kind of journey that it might be, or could be, “for real.” In the time that has passed since this caminata nocturna, or “night walk” as the simulation is called, the question, “Can you make it to California?” remains there in that silence both awkwardly and ominously, a hollow echo of a question undoubtedly uttered in desperation by some of the roughly 600,000 plus migrants who attempt to cross illegally into the United States every year.2 If we think of the border as an interpellating force that hails and constitutes the identities to whom it grants passage or expels, a regulatory force that has come to constitute transnational migrant identities and fronterizas/os in movement across national boundaries, then what constitutive acts take place in a reenactment of this passage? How does a reenacted border crossing lay bare the performative force of the border? Furthermore, in this laying bare what questions does it compel us to ask about the construction of cultural identities made in the image of what Marcial Gonzalez refers to as “the most repressive and racist symbol of demarcation and exclusion produced by capitalism, nationalism, and imperialism—namely, the Natalie Alvarez is an assistant professor at Brock University’s Department of Dramatic Arts, where she teaches in the theatre praxis concentration. She has two edited books (forthcoming) on Latina/oCanadian theatre and performance with Playwrights Canada Press and is currently working on a SSHRC-funded manuscript project titled Enactments of Difference: Simulation and Performance from Military Training to Dark Tourism. 24 Journal of Dramatic Theory and Criticism border”?3 I’d like to situate the simulated border crossing in El Alberto, Mexico, as a social imaginary and praxis—that is, as a repertory of collective practices and symbolic representations with material impacts on the community—that not only constitute cultural identities but also develop a critical realism seeking to dismantle, paradoxically, the very borders that constitute them.4 The caminata nocturna takes place every Saturday night at the Parque EcoAlberto—an adventure tourism park run by the indigenous community of the Hñahñu in the municipality of Ixmiquilpan, Hidalgo, roughly three hours north of Mexico City. The rugged valley that surrounds the park’s site, thick with cacti and bushes, swamp, and steep, rocky climbs, becomes the obstacle course for a largely improvised game in which some eighty-two members of the Hñahñu community take on a variety of roles in the simulation. These community members play either the coyotes (or polleros), guiding the tourists who have paid roughly twenty US dollars each for this five- to seven-hour journey, or the US border patrol, undermining the performative power of the oppressor in an instance of Boalian Theatre of the Oppressed.5 As these “border patrol officers” chase participants in police cars, they...

The mode of reproduction in natural populations of ascomycetous fungus,Emericella nidulans, from Israel

The mode of reproduction of the soil ascomycetous fungus Emericella nidulans of Israeli populations was studied using 15 microsatellite (simple sequence repeats or SSR) trinucleotide markers. The study was performed in three canyons: two located in the northern part of Israel (Mount Carmel and western Upper Galilee) and one in the southern Negev desert. In each canyon, E. nidulans strains were isolated from the opposite slopes and (in the desert canyon) the valley bottom. Testing the reproductive structure of the populations indicated the presence of sexuality in the northern population and predominant clonality in the desert population. The predominantly clonal character of the desert population of E. nidulans was explained by the assumption that for relevant multilocus systems of a fungus, only several haplotypes can survive in the rather constant, extremely stressful desert conditions. Additionally, the very low density of E. nidulans populations in the soil of the desert canyon, which reduces the probability of finding a sexual partner, might favour predominant clonality via selfing. Increasing sexuality in E. nidulans populations on the north-facing slopes of the northern canyons may be a result of biotic stress (pressure of competitive fungal species), due to the more mild ecological conditions in these canyons.

Looking Out from the Acropolis, 1989, and: Waiting in a Desert Canyon, and: Varna Snow

Looking Out from the Acropolis, 1989, and: Waiting in a Desert Canyon, and: Varna Snow John Balaban (bio) Looking Out from the Acropolis, 1989 Each structure, in its beauty, was even then and at once antique, but in the freshness of its vigor, even today, recent and newly wrought. Plutarch, "On the Acropolis" In old-town Athens of date palms, of ferned balconiescascading canary calls, I walked with a Bulgarian friendup the stony, sunny path to the "high city" where tanglesof cactus and Spanish sword pocked the Periclean rampartsand packs of wild cats prowled the brush for mice as windwhipped the naps of their fur and Georgi's little son, Aleko,hooted after them as we trailed behind, plodding upwardthrough the gate of broken columns to the precincts of Athena,two poets, from West and East, here for the first time, awedby the lonely grace of stones fallen, stones still standing. On the left, the smiling maidens of the caryatid porchwhose marble robes fluttered in blue sky;on the right, the massive surge of Parthenon columnscapped by a parade of centaurs, horsemen, gods,reliving dramas of who we are, who we might becomeas pediments marked our battles with beasts, our talkswith gods, our search for ourselves in philosopher grovesof this city on the hill that draws us by survivingPersian navies, Roman consuls, pasha's yoke, Panzer Gruppe-holding up like a Phidean model a senseof the examined life that is worth living, a placewhere gods and men can struggle with success, strivingto widen the wealth of the human soul, the size of heaven.All across the monumental rubble, trailing after tour guides,Japanese photographed this field of broken stone. [End Page 26] As we looked out from the Acropolis, we sawthe New World Order the president praisedthat winter as caged canaries down belowsang in the sunshine of Athenian balconies:Both superpowers, bankrupt; the Japanese, our bankers.Looking east past Yugoslavian slaughter,the Kozlodui reactor was about to blow.Further east, in Tbilisi, the shoot-out at Parliament,the breadlines in Moscow, the dead rivers and lakes,the black colonels hopping in Rumpelstiltskin rageat loss of empire, as Chechens, Kurds, Azeris et al.went for their guns to settle old scores.How much has changed since then?Merely the killing fields. Then it was Israeli rubber bullets and intifada stones.Holiday shoppers at Clapham Junction bombed by Irish Santas.German skinheads bashing Vietnamese and Turks.Bloated African bellies, fly-infested eyes.Shining Path Maoists beheading Indians in Ayacucho.And nosferatu warlords in Beijing sipping their elixirof cinnabar and blood. Pol Pot vacationing in Thailand. Meanwhile, it was snowing in Chicago, snowing on the cardboard hutsof the homeless in the land of the free, as more banks failedand repossessed midwestern farms lay fallow to the wind.Each in the cell of himself was almost convinced of his freedomwhen the Wall fell to cheers of freed multitudesand one could hear communist and capitalist gasps rise up [End Page 27] in a global shout that circled the earth for a yearthen disappeared through holes in the ozone layer. The New World Order. The tribes of the Bookare still turned to wrath as the worst of uswould wind time back to savage pasts easier to imagine.The philosopher's grove is empty; the poet's words gone flat.Against this, aren't the Japanese, baptized in nuclear fire,clapping their hands for the Kami of the cash register,our safest, sanest neighbors? These old stones cry out for more,surviving centuries, sculpted for all to see,declaring our need for beauty and laws like lovefor this tiny polis of a planet spinning wildly,for my daughter, snug, asleep in her bed,for Aleko who played in the Chernobyl cloud,whose father stood near Nike's rotting frieze,looking out upon the city jammed with cars. Georgiopened his flask of vodka and poured some on a stonebefore we drank our toasts to the new world orderand to whatever muse might come to give us...

Value of Instream Recreation in the Sonoran Desert

This study investigates recreation use value for access to a Sonoran Desert canyon, and associated instream flow, through a case study of Aravaipa Canyon Wilderness. The Wilderness is one of the last perennial streams in Southern Arizona, tributary to the famed and imperiled San Pedro River. Available permit information is combined with zip-code level census data to estimate a zonal travel cost model of recreation trip demand. Estimated consumer surplus per visitor day values are $25.06 and $17.31 (in 2003 dollars), for two separate access sites. Results indicate a significant recreation value of surface water sites in the Sonoran Desert region, while the value discrepancy may imply a premium for remote recreation.

A New Genus and Species of the Tribe Attagenini (Coleoptera: Dermestidae) from the Mojave Desert of California

Apphianus yuccae, new genus and new species in the tribe Attagenini, subfamily Anthreninae, family Dermestidae is described from a Mojave Desert canyon on the eastern edge of the Sierra Nevada in Kern Co, California.

Gene expression and metabolite profiling of Populus euphratica growing in the Negev desert

A Populus euphratica DNA microarray was constructed and used to analyze gene expression in trees growing in the desert. P. euphratica is shown to express a set of genes that is different from other Populus trees and these genes contribute to adaptation to saline growth conditions.

Hoover Dam: An American Adventure

In the spring of 1931, in a rugged desert canyon on the Arizona-Nevada border, an army of workmen began one of the most difficult and daring building projects ever undertaken - the construction of Hoover Dam. Through the worst years of the Great Depression as many as five thousand laborers toiled twenty-four hours a day, seven days a week, to erect the huge structure that would harness the Colorado River and transform the American West.Construction of the giant dam was a triumph of human ingenuity, yet the full story of this monumental endeavor has never been told. Now, in an engrossing, fast-paced narrative, Joseph E. Stevens recounts the gripping saga of Hoover Dam. Drawing on a wealth of material, including manuscript collections, government documents, contemporary newspaper and magazine accounts, and personal interviews and correspondence with men and women who were involved with the construction, he brings the Hoover Dam adventure to life. Described here in dramatic detail are the deadly hazards the work crews faced as they hacked and blasted the dam's foundation out of solid rock; the bitter political battles and violent labor unrest that threatened to shut the job down; the deprivation and grinding hardship endured by the workers' families; the dam builders' gambling, drinking, and whoring sprees in nearby Las Vegas; and the stirring triumphs and searing moments of terror as the massive concrete wedge rose inexorably from the canyon floor. Here, too, is an unforgettable cast of characters: Henry Kaiser, Warren Bechtel, and Harry Morrison, the ambitious, headstrong construction executives who gambled fortune and fame on the Hoover Dam contract; Frank Crowe, the brilliant, obsessed field engineer who relentlessly drove the work force to finish the dam two and a half years ahead of schedule; Sims Ely, the irascible, teetotaling eccentric who ruled Boulder City, the straightlaced company town created for the dam workers by the federal government; and many more men and women whose courage and sacrifice, greed and frailty, made the dam's construction a great human, as well as technological, adventure. Hoover Dam is a compelling, irresistible account of an extraordinary American epic.

Hoover Dam: An American Adventure by Joseph E. Stevens

1062 Book Reviews TECHNOLOGY AND CULTURE (p. 33)—requires further elaboration to be meaningful. In the section on dams, an explanation and diagram of a turbine (since so many dams are used for power production) would have been helpful. But these are quibbles about a book that, overall, is carefully researched and written. The preservation of bridges and dams presents unique challenges, for their continued survival depends not so much on significance as on safety. While there are success stories—the state of Virginia, for example, early on completed an inventory of its historic metal truss bridges that provided a context for preserving the best examples—the book’s case studies demonstrate just how complex bridge and dam preservation can be. Fortunately, public interest in the preservation of historic bridges, at least, seems to be growing; Jackson acknowledges that dams are such prosaic structures they have yet to attract the attention of preservationists. The book’s physical dimensions—it is tall and skinny—are oddly out of sync with the expansiveness of its subjects. Apparently, the confining format was dictated by the requirements of the National Trust’s Great American Places Series, of which this guide is a part. It necessarily limits the effectiveness of the many stunning black-andwhite photographs. Nevertheless, while one might wish the book could be larger, one cannot wish for a better introduction to the astonishing range of American technology still to be seen along our roads and rivers. Carol. Poh Miller Ms. Miller is a historical consultant in Cleveland. She has documented many of that city’s bridges for the Historic American Engineering Record of the National Park Service. Hoover Dam: An American Adventure. By Joseph E. Stevens. Norman: University of Oklahoma Press, 1988. Pp. ix + 326; illustrations, notes, bibliography, index. $24.95. Stolidly filling the Black Canyon between Nevada and Arizona near Las Vegas and impounding the floodwaters of the Colorado River, the Hoover Dam is among the best-known public works structures in America. It was originally planned for Boulder Canyon under the name Boulder Dam and formally authorized by Calvin Coolidge in December 1928, but a fault line at the initial site prompted relocation of the structure about 10 miles downstream. During the Hoover administration the politically loyal secretary of interior dubbed it the Hoover Dam, while under Roosevelt’s New Deal the name reverted to Boulder Dam. Finally, the Republican-controlled Congress changed it back to Hoover Dam in the late 1940s. Despite this odyssey of nomenclature, the physical structure remained essentially unaltered TECHNOLOGY AND CULTURE Book Reviews 1063 throughout the construction process. Built by the Six Companies Inc. under the direct authority of the federal Bureau of Reclamation, the 726-foot-high concrete dam stores water for agricultural use in California’s Imperial Valley, serves municipal needs in the greater Los Angeles area (under the auspices of the Metropolitan Water District of Southern California), generates hydroelectric power (in large part used to pump water to Los Angeles users), and provides flood control for land in the lower Colorado River Valley. When completed in 1935, the massive curved gravity structure was the tallest dam in the world, and, although surpassed in height by several recent projects, it remains an enduring monument in the annals of civil engineering history. Previous works, such as Norris Hundley’s Water and the West: The Colorado River Compact and the Politics op Water in the American West (University of California Press, 1975) and Beverly Moeller’s Phil Swing and Boulder Dam (University of California Press, 1971), have examined the complex political maneuvering that attended its planning and approval. But aside from popular descriptive treatments, there has been little scholarly examination of the actual construction processes involved in erecting the dam. Now the gap has been filled with Joseph Stevens’s detailed analysis of the physical work and social interaction that occurred in the remote desert canyon between 1931 and 1935. Although Stevens pays close attention to the engineering specifically associated with the Hoover Dam, he is relatively uninterested in dam design issues within any larger technological or comparative contexts. Rather, his well-documented research is tightly focused on the “ad­ venture” of building this single...

Solitary male chacma baboons in a desert canyon

Solitary and paired adult (nine) and subadult (one) male chacma baboons, Papio ursinus, were observed over a period of years living in part of a wooded desert canyon not used by adjacent troops. These extratroop males were silent when alone and gave only one alarm vocalization, the "wa-hoo" call, when paired. The space occupied by them is unsuitable for use by troops according to criteria for adequate sleeping sites and access to water. But the foods available to them, especially figs, but also other fruits and fresh acacia seeds, were abundant. These foods are more highly preferred by baboons than those foods available to troop members. Troop members deplete these resources and shift to less preferred foods with lower water content and longer processing times. All of the adult members of the troop adjacent to these isolated males were infected with a skin disease. Isolated males were not so afflicted and so cannot have originated from, or ever been a part of, this troop. They probably moved to the space where they were observed from other inland troops, traveling to their current home range along the narrow canyon river course.

Defense of Space and Resources by Chacma (Papio Ursinus) Baboon Troops in an African Desert and Swamp

Baboons are not included in the growing body of documentation on primate spatial defense. Instead, most field studies of baboons suggest that troops occupy overlapping undefended home ranges. In southwestern Africa we found defense of space by two troops living in a Namib Desert canyon and by a population of troops on the Okavango Swamp flood—plain in Botswana. Two desert troops encountered one another at contiguous ends of their linear home ranges and established a defended boundary near a waterhole. One troop also dominated a third, a smaller troop at the opposite end of its home range. In the swamp, large troops, living in a more energy and plant species—rich environment, occupied small home ranges relative to troops studied elsewhere in Africa. Here space was defended along well—defined boundaries. Size and configuration of troop space and the arrangement of resources within each space influence the likelihood of intertroop encounters and the expression of spatial defense. See full-text article at JSTOR

Movement of the Horned Lizard Phrynosoma solare

The movement of the regal horned lizard, Phrynosoma solare, in a desert canyon 4.8 km south of Canyon Lake, Maricopa County, Arizona, was investigated by direct observation and capture-recapture methods from October, 1969 through August, 1970. Five movement patterns (two for adults, three for juveniles) were identified for Phrynosoma solare in normal activity. These movements were all correlated with the activity and stability of their main food source, the harvester ants, Pogonomyrmex rugosus. Adult P. solare either remained for a long period in a small well-defined area close to one or two trails of one or two ant mounds, or exhibited exploratory movements using active ant trails of more than three ant mounds with no apparent tendency to return to the first capture site. Fall hatchlings restricted themselves to a very small, and well-defined home range within one meter of an ant mound entrance, while larger juveniles (55-75 mm in size), during spring and summer, exhibited either a short dispersal pattern of movement, where the lizards left their first capture site and moved to a well-defined range, or a long dispersal pattern, where the lizards wandered within the study area without establishing a definite home range. Adult males averaged 15.32 m between points of capture and had a mean maximum distance between points of capture of 30.66 m, whereas females were more restricted in their movements and averaged 7.88 mm between points of capture and had a mean maximum distance between points of capture of 14.80 m.

Chacma Baboon Tactics during Intertroop Encounters

Intertroop conflicts occur regularly in populations of chacma baboons (Papio ursinus) in a desert canyon in the Namib Desert of South West Africa and in the Okavango Swamps of Botswana. These interactions range from peaceful mingling of juveniles to violent chases by adult males. Encounters may involve face-offs, coordinated group charges into the ranks of the opposing troop, intratroop herding by adult males, and vocalizations. Encounters between the desert canyon troops vary for the same troop, depending upon the alien troop encountered. In the desert, intertroop dominance was correlated with large troop size and the number of large males per troop. In the swamp, where neighboring troops shared more stable troop boundaries, intertroop interactions were more frequent and their character less variable. Adult females generally withdraw or are chased from encounter sites. When troops come together juveniles may initiate play or groom members of alien troops. Male baboons dominate intertroop encounters and are hostile in their interactions.

Ecology of the Lizard Uta mearnsi in a Desert Canyon

A large population of Uta mearnsi was observed in a desert canyon during the summer of 1963. Males and females averaged 73 and 72 mm snout-vent length, respectively. There was no apparent sexual dimorphism in size. Normal activity-temperature range of the lizard was 25-39 C. During the intense heat of the day, the lizards retired to cracks or shady overhangs and most activity ceased. A mature male and a mature female shared a territory. Each defended their territory against intruding lizards of their own sex. Greater numbers of lizards were captured around the numerous isolated water holes of the canyon floor than in areas where such water was absent. The large numbers of insects (mainly dipterans) at these water holes might account for the high population densities of this insectivorous lizard in these areas. Egg laying occurred near the end of June. No active ecological competition was observed between U. mearnsi and other lizards of the area.