John G. H. Cant

University of Puerto Rico at Ponce, Ponce, Ponce, Puerto Rico

Are you John G. H. Cant?

Claim your profile

Publications (19)56.62 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Increasing access to sterile syringes and new drug preparation materials is an effective means of reducing HIV transmission among injection drug users (IDUs), and a fundamental component of harm reduction ideology. The purpose of this study is to examine changes during a three-year period in syringe acquisition by street-recruited Puerto Rican IDUs characterized by frequent drug injection and high HIV seroprevalence. At baseline (1998-1999) and 36-month follow-up, 103 IDUs recruited in East Harlem, New York (NY), and 135 from Bayamón, Puerto Rico (PR) were surveyed about syringe sources and HIV risk behaviors in the prior 30 days. A majority of participants in both sites were male (NY 78.6%, PR 84.4%), were born in Puerto Rico (NY 59.2%, PR 87.4%), and had not completed high school (NY 56.3%, PR 51.9%). Compared to PR IDUs at follow-up, NY IDUs injected less (3.4 vs. 7.0 times/day, p < .001), and re-used syringes less (3.1 vs. 8.0 times, p < .001). Between baseline and follow-up, in NY the proportion of syringes from syringe exchange programs (SEPs) increased from 54.2% to 72.9% (p = .001); syringes from pharmacies did not increase significantly (0.2% to 2.5%, p = .095). In PR, the proportions of syringes from major sources did not change significantly: private sellers (50.9% to 50.9%, p = .996); pharmacies (18.6% to 19.0%, p = .867); SEP (12.8% to 14.4%, p = .585). The study indicates that NY SEPs became more dominant, while NY pharmacies remained a minor source even though a law enacted in 2001 legalized syringe purchases without prescription. Private sellers in PR remained the dominant and most expensive source. The only source of free syringes, the SEP, permitted more syringes to be exchanged but the increase was not statistically significant. Implications for syringe exchange and distribution programs are discussed.
    Substance Use &amp Misuse 08/2006; 41(9):1313-36. DOI:10.1080/10826080600885092 · 1.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The practice of injecting shared drugs, in which drug users prepare, divide and inject portions of a drug solution, is a means of transmitting HIV, HCV, and other blood-borne pathogens. This study examined the process of injecting shared drugs among drug users in San Juan, Puerto Rico, through detailed observations of 25 episodes of the injection of shared drugs, and by informal interviewing of episode participants. The ways in which price and packaging of drugs, access to drug preparation materials, and social and economic relations between drug-sharing "partners" influence the process of injecting shared drugs are explored. Because differential power relations, and in turn, injection drug users' exposure to HIV and HCV, are apparent in some drug-sharing partnerships, a key objective of this study was to extend our understanding of contributions or "investments" made by different drug-sharing partners, the benefits and costs that different partners experience, and the extent to which IDUs assume different partner roles. The findings of this small, in-depth qualitative study provide insight into drug users' motivations for injecting shared drugs, and suggest reasons why certain standardized, countrywide HIV/HCV intervention efforts have not been entirely successful in preventing the devastating illnesses that disproportionately affect injection drug users.
    Journal of psychoactive drugs 04/2005; 37(1):37-49. DOI:10.1080/02791072.2005.10399747 · 1.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study integrates the results of quantitative and qualitative methods to elucidate the association between sexual identity and physical and sexual abuse among Puerto Rican drug users. A structured questionnaire was administered to 800 subjects in New York and 399 in Puerto Rico. A total of 93 subjects (7.9%) self-identified as homosexual or bisexual. Gay males were significantly more likely than heterosexual males to report first occurrence of physical abuse by a family member in childhood. Both gay and bisexual males were more likely than their heterosexual counterparts to report first experiencing unwanted sex in childhood and intimate partner physical abuse later in life. Lesbians were more likely than female heterosexuals to report unwanted sex in childhood. Qualitative data were collected through in-depth life histories with 21 subjects and suggest that gay and lesbian subjects perceive antihomosexual prejudice on the part of family members as one cause of childhood physical and sexual abuse.
    The Journal of Sex Research 09/2003; 40(3):277-85. DOI:10.1080/00224490309552192 · 2.70 Impact Factor
  • Source
    John G H Cant · Dionisios Youlatos · Michael D Rose ·
    [Show abstract] [Hide abstract]
    ABSTRACT: A comparative field study of the locomotion of woolly monkeys (Lagothrix lagothricha) and spider monkeys (Ateles belzebuth) in undisturbed rainforest of northeastern Ecuador reveals substantial differences in their use of suspensory modes. Ateles performed both more brachiation (by forelimbs and tail, with trunk rotation), and forelimb swing (similar to brachiation, but without trunk rotation) than Lagothrix. In contrast, in Lagothrix 20% of suspensory movement was by pronograde forelimb swing, which resembles forelimb swing except that the body is held in a pronograde orientation due to the tail and/or feet intermittently grasping behind the trailing forelimb. Ateles never exhibited this mode. Both brachiation and forelimb swing by Ateles were more dynamic than in Lagothrix, consisting of higher proportions of full-stride bouts (versus single-step). Both species used smaller supports for suspensory than for quadrupedal locomotion, and Ateles used both smaller and larger supports for suspension than did Lagothrix. Analysis of support inclination shows that both species tended to perform more above-support movement on horizontal supports and more below-support (suspensory) movement from oblique supports. Our attempt to elucidate the aspects of canopy structure that favor suspension suggests the need for additional kinds of observational data, focusing on the "immediate structural context" of positional events.
    Journal of Human Evolution 07/2003; 44(6):685-99. DOI:10.1016/S0047-2484(03)00060-5 · 3.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study examines gender and developmental stage differences in physical and sexual abuse among Puerto Rican drug users. A structured questionnaire was administered to 799 participants in New York and 382 in Puerto Rico. Qualitative data were collected through in-depth life histories with 21 participants. Study participants included 297 female and 884 male Puerto Rican drug injectors and crack smokers. Females were significantly more likely than males to report physical abuse by a family member in childhood and unwanted sex in childhood, adolescence, and adulthood. Qualitative findings describe abuse in the contexts of family, drug dealing, drug paraphernalia possession, and sex work.
    Violence Against Women 07/2003; 9(7):839-858. DOI:10.1177/1077801203009007005 · 1.33 Impact Factor
  • Source
    John G.H. Cant · Dionisios Youlatos · Michael D. Rose ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Field study of the locomotor behavior of sympatric woolly monkeys (Lagothrix lagothricha) and spider monkeys (Ateles belzebuth) in undisturbed rainforest of northern Ecuador revealed similar patterns in use of plant forms (categorized tree and liana structure), and substantial differences in the frequencies of use of different grouped modes (aggregates of kinematically similar specific modes). Lagothrix progressed more than Ateles by leaping/dropping and quadrupedal walking/running, whereas Ateles exhibited more suspensory locomotion. Grouped modes are associated with different plant forms in similar ways in the two species. In contrast, the species differed in use of tree zone (trunk/bole, major branches, intermediate branches, and terminal branches), with Lagothrix using intermediate branches and Ateles terminal branches more. Correlated with this difference was greater use by Lagothrix of quadrupedal movement, especially on intermediate branches, and greater use of suspensory modes by Ateles, especially in the terminal zone. Further research is needed to determine how these patterns are facilitated and constrained by morphological mechanisms. Analysis of specific locomotor modes within groups shows several interspecific differences in relative frequencies.
    Journal of Human Evolution 09/2001; 41(2):141-66. DOI:10.1006/jhev.2001.0485 · 3.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Quantitative and qualitative data are used to compare alternative sources of syringes, including syringe exchange programs (SEPs), accessed by 165 Puerto Rican injection drug users (IDUs) in East Harlem, New York (NY), and 115 in Bayamn, Puerto Rico (PR). IDUs in PR obtained, on average, 45.2% of their syringes from syringe sellers, 18.0% from pharmacies, and 17.6% from a SEP. By contrast, IDUs in NY obtained 55.0% of their syringes from SEPs and 22.9% from syringe sellers. Compared to their island counterparts, IDUs in NY received significantly more syringes from SEPs (NY, 104.5; PR, 9.2) in the prior 30 days, and were more likely to be referred by SEPs to drug treatment and HIV/TB-testing services. The results of this study suggest the need in Puerto Rico to eliminate restrictive syringe exchange policies, reform drug paraphernalia laws to protect SEP clients, and address police harassment related to carrying syringes.
    AIDS and Behavior 11/2000; 4(4):341-351. DOI:10.1023/A:1026498321919 · 3.49 Impact Factor
  • Jean E. Turnquist · Daniel Schmitt · Michael D. Rose · John G. H. Cant ·

  • Jean E. Turnquist · Daniel Schmitt · Michael D. Rose · John G.H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Pendular motion during brachiation of captive Lagothrixlagothricha lugens and Atelesfusciceps robustus was analyzed to demonstrate similarities, and differences, between these two closely related large bodied atelines. This is the first captive study of the kinematics of brachiation in Lagothrix. Videorecordings of one adult male of each species were made in a specially designed cage constructed at the DuMond Conservancy/Monkey Jungle, Miami, FL. Java software (Jandel Scientific Inc., San Rafael, CA) was used for frame-by-frame kinematic analysis of individual strides/steps. Results demonstrate that the sequence of hand and tail contacts differ significantly between the two species with Lagothrix using a new tail hold with every hand hold, while Ateles generally utilizes a new tail hold with only every other hand hold. Stride length and stride frequency, even after adjusting for limb length, also differ significantly between the two species. Lagothrix brachiation utilizes short, choppy strides with quick hand holds, while Ateles uses long, fluid strides with longer hand holds. During brachiation not only is Lagothrix's body significantly less horizontal than that of Ateles but also, within Ateles, there are significant differences between steps depending on tail use. Because of the unique nature of tail use in Ateles, many aspects of body positioning in Lagothrix more closely resemble Ateles steps without a simultaneous tail hold rather than those with one. Overall pendulum length in Lagothrix is shorter than in Ateles. Tail use in Ateles has a significant effect on maximum pendulum length during a step. Although neither species achieves the extreme pendulum effect and long period of free-flight of hylobatids in fast ricochetal brachiation, in captivity both consistently demonstrate effective brachiation with brief periods of free-flight and pendular motion. Morphological similarities between ateline brachiators and hylobatids are fewer and less pronounced in Lagothrix than in Ateles. This study demonstrates that Lagothrix brachiation is also less hylobatid-like than that of Ateles. Am. J. Primatol. 48:263–281, 1999. © 1999 Wiley-Liss, Inc.
    American Journal of Primatology 01/1999; 48(4):263 - 281. DOI:10.1002/(SICI)1098-2345(1999)48:4<263::AID-AJP2>3.0.CO;2-9 · 2.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: As quantitative studies on primate positional behavior accumulate the lack of a standard positional mode terminology is becoming an increasingly serious deficiency. Inconsistent use of traditional terms and inappropriate conflation of mode categories hamper interspecific and interobserver comparisons. Some workers use common terms without definition, allowing at least the possibility of misunderstanding. Other researchers coin neologisms tailored to their study species and not clearly enough defined to allow application to other species. Such neologisms may overlap, may completely encompass, or may conflate previously defined labels. The result is, at best, the proliferation of synonyms and, at worst, the creation of confusion where clarity had existed. Historical precedents have sometimes resulted in “catch-all” terms that conflate any number of kinematically different behaviors (e.g. “brachiation,” “climbing,” and “quadrumanous climbing”). We recognize three areas where distinction of positional modes has some current importance: (1) Modes that require humeral abduction should be distinguished from adducted behaviors; (2) locomotor modes that involve ascent or descent should be distinguished from horizontal locomotor modes; and (3) suspensory modes should be distinguished from supported modes. We recommend a nomenclature that is not dedicated to or derived from any one taxonomic subset of the primates. Here we define 32 primate positional modes, divided more finely into 52 postural sub-modes and 74 locomotor sub-modes.
    Primates 09/1996; 37(4):363-387. DOI:10.1007/BF02381373 · 1.34 Impact Factor
  • Daniel J. Povinelli · John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: A fundamentally new psychology related to the ability to conceive of limited aspects of the self may have evolved in the ancestor of the great ape/human clade. Existing models of the evolution of primate intelligence do not provide an adequate explanation of the apparent restriction of this phenomenon. We propose that the capacity for self-conception evolved as a psychological mechanism enabling large-bodied, highly arboreal apes to cope with problems posed by the need to negotiate their way through a habitat that was fragile due to their body size. First, we briefly outline the case for believing that a new psychology related to self-conception evolved during the Miocene in the ancestor of the great ape/human clade. Next, we examine the existing models of the evolution of primate intelligence and assess their ability to account for the evolution of self-conception. Finally, we offer details of our alternative model, along with a series of predictions that can be derived from it.
    The Quarterly Review of Biology 01/1996; 70(4):393-421. DOI:10.1086/419170 · 4.89 Impact Factor
  • John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: The rationale for most field studies of the positional behavior of arboreal primates has been the need to document natural behaviors quantitatively in order to infer the functional significance of morphological configurations. This focus on interactions of morphology with behavior is justifiable, but there exists another important level of biological relationships, that of the animal with its structural habitat, which it must negotiate to find food and avoid being preyed on. Recently it has become apparent that body size is likely to affect relationships of positional behavior with habitat structure, as well as with morphology. Here I offer a framework for research on functional relationships of positional behavior, body size, and habitat structure, with the ultimate objective of elucidating the aptive significance of the great diversity exhibited by arboreal primates. This approach specifies several distinct problems that animals solve, and indicates how research might be directed at revealing the relative effectiveness with which different primates solve them. A preliminary application of the framework examines sympatric north Sumatran primates.
    American Journal of Physical Anthropology 07/1992; 88(3):273-83. DOI:10.1002/ajpa.1330880302 · 2.38 Impact Factor
  • John G.H. Cant ·

    Trends in Ecology & Evolution 03/1991; 6(3):100. DOI:10.1016/0169-5347(91)90184-Y · 16.20 Impact Factor
  • John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Although the majority of extant primates are described as "quadrupedal," there is little information available from natural habitats on the locomotor and postural behavior of arboreal primate quadrupeds that are not specialized for leaping. To clarify varieties of quadrupedal movement, a quantitative field study of the positional behavior of a highly arboreal cercopithecine, Macaca fascicularis, was conducted in northern Sumatra. At least 70% of locomotion in travel, foraging, and feeding was movement along continuous substrates by quadrupedalism and vertical climbing. Another 14-25% of locomotion was across substrates by pronograde clambering and vertical clambering. The highest frequency of clambering occurred in foraging for insects, and on the average smaller substrates were used in clambering than during quadrupedal movement. All postural behavior during foraging and feeding was above-substrate, largely sitting. Locomotion across substrates requires grasping branches of diverse orientations, sometimes displaced away from the animal's body. The relatively low frequency of across-substrate locomotion appears consistent with published analyses of cercopithecoid postcranial morphology, indicating specialization for stability of limb joints and use of limbs in parasagittal movements, but confirmation of this association awaits interspecific comparisons that make the distinction between along- and across-substrate forms of locomotion. It is suggested that pronograde clambering as defined in this study was likely a positional mode of considerable importance in the repertoire of Proconsul africanus and is a plausible early stage in the evolution of later hominoid morphology and locomotor behavior.
    American Journal of Physical Anthropology 05/1988; 76(1):29-37. DOI:10.1002/ajpa.1330760104 · 2.38 Impact Factor
  • Source
    Richard F. Kay · John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Estimates were made of the tooth wear and the number of cementum annuli on lower first molars of Macaca mulatta of known age that had lived on Cayo Santiago, Puerto Rico. It is demonstrated that both these measurements are significantly correlated with age. Neither measurement by itself, however, strongly enough corrected with age to provide a reliable guide to the true age of individuals older than about 14 years, although cementum annulus counts clearly provide a more reliable guide to age determination than does wear. A combination of tooth wear and annulus number is a somewhat better predictor of age, with a multiple regression explaining 19% of the overall variance in age. As has been reported previously in tropical ungulates, there is more than one cementum annulus per year deposited on the M1S of our sample. Comparison with rainfall data indicates that the number of dry intervals in the animal's life corresponds on a one-to-one basis with the number of annuli. It is hypothesized that such dry intervals cause nutritional stress, which in turn is reflected in periods of arrested or slowed growth in the tooth cementum. Also, more annuli are formed per year on the teeth of males than those of females. Stress engendered by intermale competition may play a role in this phenomenon.
    American Journal of Primatology 01/1988; 15(1):1 - 15. DOI:10.1002/ajp.1350150103 · 2.44 Impact Factor
  • Source
    R.F. Kay · J.G.H. Cant ·

    American Journal of Primatology 01/1988; 15:1-16. · 2.44 Impact Factor
  • John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Male orangutans (Pongo pygmaeus) weigh about twice as much as females. Observations in northern Sumatra of adults of both sexes (one male, three females) feeding in the same trees reveal the effects of body size dimorphism on feeding behavior: The male tended to use larger branches than the females, and to employ above-branch postures (sitting and standing) with greater frequency. The females employed suspensory under-branch postures more often. When feeding techniques were variable, the male tended to pull in branches to detach food with the mouth, whereas the female plucked more fruit by hand. By controlling for postcranial morphology and habitat structure, these results provide the first rigorous quantitative test of predictions about the effects of body size on primate positional behavior, and raise further questions about sexual diethism in feeding postural behavior of primates of varying absolute size.
    American Journal of Physical Anthropology 10/1987; 74(2):143 - 148. DOI:10.1002/ajpa.1330740202 · 2.38 Impact Factor
  • John G. H. Cant ·
    [Show abstract] [Hide abstract]
    ABSTRACT: Observational data were collected on the positional behavior of habituated adult female orangutans in the rain forest of the Kutai National Park, East Kalimantan, Indonesia. Results revealed the following about locomotion during travel: movement was concentrated in the understory and lower main canopy; and brachiation (without grasping by the feet) accounted for 11% of travel distance, quadrupedalism for 12%, vertical climbing for 18%, tree-swaying for 7%, and clambering for 51%. In climbing and clambering, the animal was orthograde and employed forelimb suspension with a mixture of hindlimb suspension and support. Thus suspension by the forelimbs occurred in at least 80% of travel. Locomotion in feeding trees resembled that during travel but with more climbing and less brachiation. Feeding was distributed more evenly among canopy levels than was travel, and use of postures (by time) included sitting 50%, suspension with the body vertical 11%, and suspension by hand and foot with the body horizontal 36%. The traditional explanation of the evolution of the distinctive hominoid postcranium stresses brachiation. More recently it has been proposed that climbing, broadly defined and partly equivalent to clambering in this study, is the most significant behavior selecting for morphology. The biomechanical similarity of brachiation and the orthograde clambering of orangutans precludes the present results from resolving the issue for the evolution of Pongo. The orangutan is by far the largest mammal that travels in forest canopy, and a consideration of the ways that its positional behavior solves problems posed by habitat structure, particularly the tapering of branches and gaps between trees, indicates that suspensory capacities have been essential in permitting the evolution and maintenance of its great body size.
    American Journal of Primatology 01/1987; 12(1):71-90. DOI:10.1002/ajp.1350120104 · 2.44 Impact Factor
  • Source
    Jochen Barth · Daniel J Povinelli · John G. H. Cant ·

Publication Stats

765 Citations
56.62 Total Impact Points


  • 1987-2006
    • University of Puerto Rico at Ponce
      Ponce, Ponce, Puerto Rico
  • 2005
    • Central University of the Caribbean
      • School of Medicine
      Bayamon, Cidra, Puerto Rico
  • 2003
    • University of Puerto Rico at Mayagüez
      Mayaguez, Mayaguez, Puerto Rico
  • 1987-2003
    • Polytechnic University of Puerto Rico
      San Juan, San Juan, Puerto Rico
  • 1999
    • University of Puerto Rico, Medical Sciences Campus
      San Juan, San Juan, Puerto Rico