Saimiri sciureus (Linnaeus, 1758)

Voss, Robert S. & Fleck, David W., 2011, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 1: Primates, Bulletin of the American Museum of Natural History 2011 (351), pp. 1-81 : 38-41

Saimiri sciureus (Linnaeus, 1758)

VOUCHER MATERIAL (TOTAL 5 22): Boca Río Yaquerana (FMNH 88866), Marupa (AMNH 98269, 98270), Nuevo San Juan (AMNH 268245, 268246; MUSM 11155, 11156, 11158, 11159, 11161–11169), Quebrada Esperanza (FMNH 88867), San Fernando (FMNH 88865), Santa Cecilia (FMNH 86977).

UNVOUCHERED OBSERVATIONS: Actiamë ( Amanzo, 2006), Choncó ( Amanzo, 2006), Itia Tëbu ( Amanzo, 2006), Jenaro Herrera ( Aquino, 1978), Río Orosa ( Freese et al., 1982), Reserva Comunal Tamshiyacu-Tahuayo ( Puertas and Bodmer, 1993; Heymann and Aquino, 1994), Río Yavarí (left bank below Angamos; Salovaara et al., 2003), Río Yavarí-Mirím ( Salovaara et al., 2003).

IDENTIFICATION: Despite several decades of behavioral, chromosomal, morphological, and molecular research (reviewed by Hersh-

kovitz, 1984; Thorington, 1985; Costello et al., 1993; Boinski and Cropp, 1999; Lavergne et al., 2010), the taxonomy of Saimiri (squirrel monkeys) remains profoundly unsatisfactory. The last formal taxonomic treatment of the genus ( Hershkovitz, 1984) recognized a Central American species, S. oerstedi (Reinhardt, 1872) and three Amazonian species. The latter (in Hershkovitz’s classification) consist of S. boliviensis (I. Geoffroy and de Blainville, 1834) , S. sciureus (Linnaeus, 1758) , and S. ustus (I. Geoffroy, 1843) . A fourth Amazonian species, S. vanzolinii Ayres, 1985 , was also recognized as valid by Groves (2001, 2005).

Saimiri boliviensis and S. sciureus have both been reported from the Yavarí- Ucayali interfluve. Based on his examination of museum specimens, Hershkovitz (1984) reported that S. boliviensis and S. sciureus occur sympatrically west of the Río Tapiche, whereas only S. sciureus occurs east of the Tapiche. Puertas and Bodmer (1993), however, reported unvouchered sightings of both species from the Reserva Comunal Tamshiyacu-Tahuayo (along the Quebrada Blanco and the Río Yavarí- Mirím), and Bennett et al. (2001) reported unvouchered sightings of S. boliviensis from both banks of the Tapiche. Given the discrepancy between Hershkovitz’s specimen-based observations and the unvouchered observations of fieldworkers, the external characters by which S. boliviensis and S. sciureus can be distinguished are obviously relevant for assessing the reliability of sight identifications.

The only external characters by which Peruvian forms of Saimiri boliviensis and S. sciureus can be reliably distinguished are facial markings and caudal pelage: (1) As illustrated by Hershkovitz (1984: fig. 1 ), a broad arc of white fur extends onto the forehead above each eye in S. sciureus , separating the blackish superciliary vibrissae from the dark (greyish or blackish) fur of the crown; by contrast, the dark fur of the crown extends ventrally to the superciliary vibrissae in S. boliviensis , such that the vibrissae are harder to see. (2) The black tuft of long hairs at the end of the tail is thicker and more conspicuous in S. sciureus than in S. boliviensis . Unfortunately, neither of these char- acters is easily scored at a distance or in the absence of comparative material, and relevant illustrations in some field guides are inaccurate. 12 Because primatologists have seldom described the phenotypic criteria they used to identify squirrel monkeys in the field, most unvouchered observations of Saimiri from northeastern Peru cannot be reliably assigned to species.

All of the specimens of Saimiri that we examined from east of the Río Tapiche in the Yavarí-Ucayali interfluve are unambiguously referable to S. sciureus (sensu Hershkovitz, 1984) . Among other diagnostic traits, all examined specimens have broad arcs of white fur above each eye (separating the blackish superciliary vibrissae from the grayish or blackish coronal fur), and the black tail tufts of these specimens are longer and thicker than those in comparative series of S. boliviensis . Males have grayish-agouti coronal fur and grayish sideburns, whereas the coronal fur and sideburns of females are conspicuously darker (sometimes blackish in part; e.g., AMNH 268246, FMNH 88867, MUSM 11166). Although the Matses report variation in arm pigmentation among local troops of squirrel monkeys (see below), all of the specimens we examined have grayishagouti upper arms and yellowish forearms. Measurement and weight data are summarized in table 12.

As recognized by authors (e.g., Hershkovitz, 1984; Groves, 2001, 2005), Saimiri sciureus is polytypic, with several subspecies that are distinguishable by pelage pigmentation and karyotypes; specimens from the Yavarí-Ucayali interfluve are usually referred to S. s. macrodon (Elliot, 1907), the type locality of which is in eastern Ecuador. Although neither S. sciureus nor S. s. macrodon are consistently recovered as monophyletic groups in recent phylogenetic analyses of cytochrome- b sequence data ( Lavergne et al., 2002, 2010), the taxonomic interpretation of these results is unclear. Absent a comprehen-

sive revision of Saimiri based on geographically dense sampling, multiple genes, and due attention to diagnostic morphological traits, we follow existing usage in referring our material to S. sciureus in its currently accepted sense.

ETHNOBIOLOGY: Squirrel monkeys are called tsanka. They are also called tsankekid ‘‘one that says tsan.’’ The term tsanka appears to be a shorted form of tsankekid. Two subtypes are recognized: tsankadapa ‘‘big squirrel monkey’’ and tsankampi ‘‘little squirrel monkey.’’ The larger variety is said to have whitish arms and to live in smaller troops (or alone), while the small variety is said to have bright yellow arms and to live in larger troops. The small variety is said to be more common in river-edge forest than the larger variety. The smaller variety is said to be the only one found to travel together with brown capuchin monkeys.

Very long ago, the Matses did not eat squirrel monkeys, lest they become thin (like a squirrel monkey). More recently, perhaps even before contact with missionaries, Matses began to eat squirrel monkeys, but as with titi monkeys, hunters usually do not make a special effort to find them because they are small. A Matses hunter may listen to their noisy rustling of branches, and then try to get a shot off before they see him. After the first shot, the hunter may chase the troop making them run through the trees until one pauses on a relatively low branch, when the hunter can shoot it with an arrow or shotgun. The Matses consider squirrel monkeys to be very abundant, easy to kill, and tasty, but nevertheless hunters do not often kill them.

The canines of large males are sometimes used to make men’s tooth necklaces, but the teeth of larger monkeys are preferred. Squirrel monkeys are frequently kept as pets and are considered very good pets by some Matses. Attractive women are called ‘‘squirrel monkey’’ because squirrel monkeys, especially their babies, are considered cute.

MATSES NATURAL HISTORY: Squirrel monkeys are cute. They have white fur around the eyes. The area around their mouth is black, as if painted with genipap dye. They have a long tail with a black tail tip, like a night monkey does. They have a strong smell.

They are found in all types of habitats, but not too far from rivers [within a few kilometers]. They prefer riverside forest and also like swamp-palm [ Mauritia flexuosa ] swamps. They like riverside forest because there are a lot of legume pods and insects there. They like swamp-palm swamps, both for the swamp-palm fruits and because there are many insects there.

They live in very large troops, and stay together without splitting up. Sometimes they eat, travel, and even sleep with brown capuchin monkeys. They may forage together with woolly monkeys, but do not stay with them as long as they do with brown capuchin monkeys. The females carry the young on their back or underside.

They vocalize saying ‘‘ sii sii chan chan chan chan sii sii.’’ When they hear brown capuchin monkeys, they answer. The young also go ‘‘ sii sii sii.’’ They yell like that as they travel noisily through the trees.

Squirrel monkeys are active during the day. They wake up early and start vocalizing right away. They always travel spastically, as if they are always hungry. They descend to the ground to drink water. They are usually found low in the forest, but they climb very high up to eat fruits or to flee from humans or predators. They sleep mostly in the fronds of palm trees such as budëd palms [ Attalea butyracea ]. They even sleep on the thorny fronds of pinchuk palms [ Astrocaryum spp. ]. They all sleep together, not spread out. They bed down making a lot of noise at dusk, when it is almost dark. Sometimes they are awake during moonlit nights.

Squirrel monkeys eat dicot tree fruits, especially legume pods such as mannan tsipuis [ Inga spp. and? Pithecellobium (Leguminosae) ] and achu inkuente [ Inga spp. (Leguminosae) ]. Other dicot fruits they eat include: wesnid dëbiate [ Anacardium giganteum (Anacardiaceae) ], këku [ Couma macrocarpa (Apocynaceae) ], mamuin [ Rheedia longifolia (Guttiferae) ], okodo mabis [undetermined sp. (Guttiferae)], moste [ Hymenaea spp. (Leguminosae) ], chichombid [ Mouriri spp. (Melastomataceae) ], şhannëd [? Brosimum (Moraceae) ], bin [ Castilla (Moraceae) ], dadain [ Clarisia racemosa (Moraceae) ], piuşh bëchi [ Helicostylis tomentosa , H. elegans (Moraceae) ], kuşhu tëbin [ Naucleopsis mello-barretoi , N. ternstroemiiflora (Moraceae) ], bata [ Pseudolmedia and Maquira spp. (Moraceae) ], poşhodi [ Passiflora nitida (Passifloraceae) ], mabis mabiskid [ Chrysophyllum prieurii (Sapotaceae) ], and kose [ Manilkara bidentata (Sapotaceae) ]. They eat swamppalm [ Mauritia flexuosa ] fruits in the dry season. They also eat a lot of spiders, crickets [or katydids; the Matses term is taxonomically ambiguous], and other insects.

Figures

Fig. 1. The Yavarí-Ucayali interfluve (shaded) in relation to surrounding geographical features of western Amazonia.

Tables

TABLE 12 External and Craniodental Measurements (mm) and Weights (g) of Saimiri sciureus from the Yavarí- Ucayali Interfluve

	Males a	Females b
HBL	307 (301–319) 6	298 (288–305) 5
LT	434 (396–464) 6	440 (420–463) 4
HF	93 (90–95) 8	92 (88–97) 5
Ear	30 (27–32) 7	30 (27–33) 5
CIL	47.7 (43.6–51.2) 9	45.1 (41.4–47.5) 8
OB	35.7 (32.3–38.6) 9	34.7 (32.0–37.6) 8
POC	31.0 (29.0–32.6) 9	30.2 (29.5–30.8) 7
ZB	40.8 (37.6–44.0) 9	37.9 (35.2–40.1) 8
BB	36.6 (34.7–37.9) 9	36.1 (34.4–37.0) 8
PPL	23.5 (21.7–25.4) 9	21.6 (19.8–22.6) 8
LMT	17.8 (16.9–19.0) 8	16.3 (14.9–17.0) 7
BM1	4.2 (4.0–4.4) 9	4.0 (3.6–4.2) 8
M1–M1	20.0 (18.4–21.6) 8	18.9 (17.8–19.9) 8
I2–I2	9.7 (9.3–10.6) 6	9.6 (9.2–10.1) 7
Weight	1131 (842–1385) 7	939 (883–969) 3

a

Summary statistics (mean, observed range in parentheses, and sample size) for measurements of AMNH 268245, 98269; FMNH 88865; MUSM 11159, 11161, 11162, 11165, 11167, 11168.

b

Summary statistics (mean, observed range in parentheses, and sample size) for measurements of AMNH 268246, 98270; FMNH 86977, 88866, 88867; MUSM 11158, 11163, 11166.