The Cebus Monkey (Cebus apella)

Abstract

Metric features and modular and laminar distributions of intrinsic projections of area 17 were studied in Cebus apella. Anterogradely and retrogradely labeled cell appendages were obtained using both saturated pellets and iontophoretic injections of biocytin into the operculum. Laminar and modular distributions of the labeled processes were analyzed using Nissl counterstaining, and/or cytochrome oxidase and/or NADPH-diaphorase histochemistry. We distinguished three labeled cell types: pyramidal, star pyramidal and stellate cells located in supragranular cortical layers (principally in layers IIIa, IIIb α, IIIb ß and IIIc). Three distinct axon terminal morphologies were found, i.e., Ia, Ib and II located in granular and supragranular layers. Both complete and partial segregation of group I axon terminals relative to the limits of the blobs of V1 were found. The results are compatible with recent evidence of incomplete segregation of visual information flow in V1 of Old and New World primates.

Urinary Excretion of Oestradiol-17β in the Female Cycle of Goeldi’s Monkeys (Callimico goeldii)

“…Such a trough has not been reported previously for oestrogen cycles de termined for other New World monkeys: Saimiri [35,36], Aotus [37][38][39][40], Cebus [41][42][43], Saguinus [19,20], Callithrix [6,7,15]. Nevertheless, if urine samples are not col lected regularly every day, such a transitory trough might easily be missed.…”

Seasonal Variation in the Testicular Volume of Capuchin Monkeys (Cebus apella) in Captivity

“…Many authors have noted that, after puberty, female capuchin monkeys show fertile cycles all year round [Hamlett, 1939;Nagle and Denari, 1983]. On the other hand, it is well documented that there is a clear peak of births during the dry season in both free-living [Hamlett, 1939] and captive colonies [Welker et al, 1983].…”

“…The period when the highest number of copulations occur coincides with the period when the largest testicular volumes are observed, and this occurs about five months before the reported period for the peak of births. Five months is approximately the gestation period described for this species [Hamlett, 1939;Nagle and Denari, 1983], leading to the conclusion that pregnancy was achieved during the period of major testicular volumes. These results strongly suggest that the seasonal variation in births in capuchin monkeys can be determined by seasonal variation in male fertility, and the total testicular volume measurement can be used as an indirect, non-invasive method to assess this variation.…”

“…Neotropical primates display many different breeding strategies. Female capuchin monkeys (Cebus apella), for instance, having reached puberty, have fertile cycles year-round [Hamlett, 1939;Nagle and Denari, 1983]. Interestingly, there are reports of a clear peak of births in free-living [Hamlett, 1939] and captive colonies [Welker et al, 1983] in the dry season, i.e.…”

Three Apparent Cases of Infanticide by Males in Wild White-Faced Capuchins (Cebus capucinus)

“…Assuming a 160-day gestation period, as confirmed for Cebus apella [Nagle & Denari, 1983], PA was conceived in mid-to late-November 1998. At that time there were no observers at the study site.…”