(1) The strength and quality of the relationship between heterosexual pairmates were compared in two species of New World monkeys, the polygynous squirrel monkey (Saimiri) and the monogamous titi monkey (Callicebus).
(2) In nature titi monkeys spend virtually all of their time in trees.
(3) At some magic moment, at the age of about 11, I withdrew Kim from a public library in a silent New Zealand suburb and discovered the great adventure of iden tity, intrigue and India, and several other things too, including the extraordinary potency of words.
(4) Vocalizations of titi monkeys were recorded from 6 groups at two sites in the Ilanos of Colombia during 8 months of study.
(5) Most male titi monkeys showed an increase in plasma cortisol in the presence of a male intruder; this pattern was not seen in their response to a female intruder.
(6) The species studied were the titi (Callicebus mollach).
(7) Female titi monkeys showed no consistent pattern of adrenocortical response to intruders of either sex.
(8) The occurrence of dermatophilosis in the titi monkey is reported.
(9) The behaviours and food types associated with wild titi monkey food transfer are described and analyzed.
(10) Titi monkeys, but not squirrel monkeys, responded to separation with a significant increase in plasma cortisol and in behavioral indices of agitation or distress.
(11) Newborns were assessed for their recovery of head turning toward laterally presented auditory stimuli (titi) that varied from a familiar standard on 1 of 5 levels of fundamental frequency.
(12) Given that three of these genera (Leontopithecus, Chiropotes and Brachyteles) can no longer be obtained from animal dealers because of exportation laws, the authors were fortunate to acquire representatives of the remaining two genera: Callicebus (titi monkeys) and Pithecia (sakiwinkis).
(13) The results suggest that an abstract representation of a tree branch attracts and guides locomotion in titis, and that responsiveness to substrate characteristics contributes to arboreality in this species.
(14) However, very high total plasma cortisol together with low CBG binding capacity and affinity result in free cortisol concentrations of 1-4 microM in some New World primates (squirrel monkey and marmosets) but not in others such as the titi and capuchin.
(15) Squirrel monkeys (Saimiri sciureus) and titi monkeys (Callicebus moloch) were studied in tasks involving reaching for food in near space (arm's reach).
(16) The in vitro excystation process of sporozoites of Isospora arctophitheci Rodhain, 1933 from the titi marmoset Saguinus geoffroyi and of Isospora bigemina (Stiles, 1891) Lühe, 1906 from the bobcat, Lynx rufus is presented.
(17) For titi monkeys, the presence of an intruder resulted in a marked increase in behavioral signs of agitation, which were more prominent in the subject of the same sex as the intruder.
(18) The present study examined the behaviours shown by male and female titi monkeys (Callicebus moloch) toward an opposite-sex stranger, and the effect of their pairmate's absence or presence on these encounters.