Ingestive behaviors in bearded capuchins (Sapajus libidinosus).

The biomechanical and adaptive significance of variation in craniodental and mandibular morphology in fossil hominins is not always clear, at least in part because of a poor understanding of how different feeding behaviors impact feeding system design (form-function relationships). While laboratory studies suggest that ingestive behaviors produce variable loading, stress, and strain regimes in the cranium and mandible, understanding the relative importance of these behaviors for feeding system design requires data on their use in wild populations. Here we assess the frequencies and durations of manual, ingestive, and masticatory behaviors from more than 1400 observations of feeding behaviors video-recorded in a wild population of bearded capuchins (Sapajus libidinosus) at Fazenda Boa Vista in Piauí, Brazil. Our results suggest that ingestive behaviors in wild Sapajus libidinosus were used for a range of food material properties and typically performed using the anterior dentition. Coupled with previous laboratory work indicating that ingestive behaviors are associated with higher mandibular strain magnitudes than mastication, these results suggest that ingestive behaviors may play an important role in craniodental and mandibular design in capuchins and may be reflected in robust adaptations in fossil hominins.

Polymorphism of the 3'-UTR of the dopamine transporter gene (DAT) in New World monkeys.

Genetic polymorphism in the 3'-untranslated region (3'-UTR) of the dopamine transporter (DAT) gene has been reported in both human and nonhuman primates, and the variable number of tandem repeats (VNTR) polymorphism has been related to several neurological and psychiatric disorders. As New World primates have been employed as models in biomedical research in these fields, in the present study we assessed genetic variation in the DAT gene in 25 robust capuchin monkeys (Sapajus spp.) and 39 common marmosets (Callithrix jacchus). Using enzymatic amplification followed by sequencing of amplified fragments, a VNTR polymorphism in the 3'-UTR region of the DAT gene was identified in both robust capuchins and common marmosets. The polymorphic tandem repeat of 40-bp basic units is similar to the human VNTR consensus sequence, with size variants composed of 9, 10, and 11 units in marmosets and 8, 9, 13, and 17 basic units in capuchins. We found behavioral evidence that carrying the 10-repeat DAT allele promotes flexible choice and maximization of foraging in marmosets tested in an operant choice paradigm. Moreover, in an intertemporal choice task, capuchins with longer repeat variants show less self-controlled choices than capuchins with at least one short repeat variant. Future research should focus on the relationship between these DAT polymorphisms, dopamine reuptake via the dopamine transporter, and behavioral and cognitive variation across New World monkey individuals.

Epidural anesthesia in capuchin monkeys (Sapajus libidinosus).

BACKGROUND: Many primates are kept in breeding for scientific or conservation purposes, but much of the clinical care is represented by trauma. To provide more effective interventions in some of these cases, the present study aimed to evaluate the technique of local anesthesia through the epidural space in capuchin monkeys (Sapajus libidinosus). METHODS: Ten animals were used, which have been deposited in the epidural space 1% lidocaine at a dose of 0.3 ml/kg over the lumbosacral joint. Heart and respiratory rates, oxygen saturation in arterial hemoglobin, blood pressure, rectal temperature, nociception, and cutaneous sensitivity were assessed before and after application. RESULTS: The technique promoted loss of sensation of the skin and muscle relaxation of the pelvic limbs, tail, and perineal region for a period of 35 minutes without any of the physiological parameters measured varies beyond normal values. CONCLUSIONS: The technique proved easy to perform, safe, and effective.