Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.

The root of modern human warfare lies in the lethal coalitionary violence of males in small-scale societies. However, there is a paucity of quantitative data concerning the form and function of coalitionary violence in this setting. Debates exist over how lethal coalitions are constituted, as well as the motivations and benefits for males to join such groups. Data from a lowland Amazonian population, the Waorani of Ecuador, illuminate three issues: (i) the degree to which raiding parties are composed of groups of fraternal kin as opposed to strategic alliances of actual or potential affinal kin; (ii) the extent to which individuals use pre-existing affinal ties to motivate others to participate in war or leverage warfare as a mechanism to create such ties; and (iii) the extent to which participation in raiding is driven by rewards associated with future marriage opportunities. Analyses demonstrate that Waorani raiding parties were composed of a mix of males who were potential affines, actual affines and fraternal kin, suggesting that men used pre-existing genetic, lineal and social kin ties for recruiting raid partners and used raiding as a venue to create novel social relationships. Furthermore, analyses demonstrate that males leveraged raiding alliances to achieve marriage opportunities for themselves as well as for their children. Overall, it appears that a complex set of motivations involving individual rewards, kin marriage opportunities, subtle coercion and the assessment of alliance strength promote violent intergroup conflict among the Waorani. These findings illustrate the complex inter-relationships among kin selection, coalition building and mating success in our species.

Life histories, blood revenge, and reproductive success among the Waorani of Ecuador.

The Waorani may have the highest rate of homicide of any society known to anthropology. We interviewed 121 Waorani elders of both sexes to obtain genealogical information and recollections of raids in which they and their relatives participated. We also obtained complete raiding histories of 95 warriors. An analysis of the raiding histories, marital trajectories, and reproductive histories of these men reveals that more aggressive warriors have lower indices of reproductive success than their milder brethren. This result contrasts the findings of Chagnon [Chagnon N (1988) Science 239:985-992] for the Yanomamo. We suggest that the spacing of revenge raids may be involved in the explanation of why the consequences of aggressiveness differ between these 2 warlike lowland South American peoples.

The cardiorespiratory effects of a fentanyl infusion following acepromazine and glycopyrrolate in dogs.

We investigated whether the analgesic mu-opioid fentanyl can be used safely in dogs in everyday clinical veterinary practice, with limited and non-invasive monitoring. To this end, the cardiorespiratory effects of fentanyl, administered in doses reported to be adequate for inducing opiate analgesia in spontaneously breathing canine patients, were evaluated by measuring the respiration rate, oxygen saturation (SpO2), heart rate, respiratory sinus arrhythmia (RSA), and rectal body temperature. Ten Beagle dogs, all spontaneously breathing room air, underwent three separate sessions in which they received in random order either saline, fentanyl 5 microg/kg/h or fentanyl 10 microg/kg/h. Each session started with a non-medication period, followed by acepromazine with glycopyrrolate, followed by a loading dose and infusion of saline or fentanyl, and ended with the administration of the antagonist naloxone. At the doses studied, fentanyl did not significantly change the respiration rate or have a clinically relevant effect on SpO2 or RSA, whereas it significantly decreased the heart rate and core body temperature. In the dose range tested and under the conditions described in this protocol, we conclude that fentanyl can be safely administered to healthy dogs spontaneously breathing room air.

Investigation of the interaction between buprenorphine and sufentanil during anaesthesia for ovariectomy in dogs.

OBJECTIVE: To investigate the effect of buprenorphine pre-treatment on sufentanil requirements in female dogs undergoing ovariectomy. STUDY DESIGN: Randomized, 'blinded', prospective clinical study. ANIMALS: Thirty healthy female dogs referred for ovariectomy. MATERIALS AND METHODS: Dogs were randomly assigned to one of two pre-anaesthetic treatment groups. Those in the buprenorphine group (B) received buprenorphine 20 microg kg(-1) and acepromazine 0.03 mg kg(-1) IM. Control group (C) animals received an equal volume of NaCl 0.9% and acepromazine 0.03 mg kg(-1) IM. The anaesthetic technique was identical in both groups. Pre-anaesthetic medication consisted of intravenous (IV) sufentanil (1.0 microg kg(-1)) and midazolam (0.05 mg kg(-1)) and intramuscular atropine (0.03 mg kg(-1)). Anaesthesia was induced with propofol and maintained with a constant rate infusion of sufentanil (1.0 microg kg(-1) hour(-1)) and with oxygen-isoflurane. Ventilation was controlled mechanically. Ovariectomy was performed using a standard technique. Baseline heart rate (HR) and direct mean arterial blood pressure (MAP) were recorded before the first incision. Increases in HR and MAP of > or =20% over baseline and, or spontaneous ventilation were controlled using IV sufentanil (1.0 microg kg(-1)) repeated after 5 minutes if haemodynamic variables remained elevated or attempts at spontaneous ventilation persisted. Analysis of variance was used to determine group differences in mean and median HR and MAP and to compare the maximum HR and MAP attained during surgery. Poisson regression was used to compare the number of sufentanil injections required in both groups. RESULTS: Group B required 2.46 times more sufentanil injections (p = 0.00487) than dogs in group C to maintain haemodynamic stability and prevent spontaneous ventilation during surgery. Group B dogs also had a significantly higher (p = 0.034) marginal mean of the log maximum MAP (4.756 +/- 0.036) compared with group C (4.642 +/- 0.036). CONCLUSIONS: Pre-treatment with buprenorphine appears to negatively influence the antinociceptive efficacy of intra-operative sufentanil. CLINICAL RELEVANCE: Withholding buprenorphine therapy 6-8 hours before anaesthesia incorporating pure mu receptor agonists is probably advisable. Alternative methods of analgesia should be provided in this period.