| 1. |
- Kopsch, Nora T., et al.
(författare)
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A cooperation experiment with white-handed gibbons (Hylobates lar)
- 2023
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365. ; 64:5, s. 483-492
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative behaviors among individuals of numerous species play a crucial role in social interactions. There is a special interest in investigating the occurrence of cooperation among apes because this knowledge could also shed light on evolutionary processes and help us understand the origin and development of cooperation in humans and primates in general. Gibbons are phylogenetically intermediate between the great apes and monkeys, and therefore represent a unique opportunity for comparisons. The aim of the present study was to discover whether or not white-handed gibbons (Hylobates lar) show cooperative behaviors. In order to test for the respective behaviors, the gibbons were presented with a commonly used experimental cooperative rope-pulling task. The gibbons in this study did not exhibit cooperative behaviors during the problem-solving task. However, prior training procedures could not be fully completed, hence this project constitutes only the onset of exploring cooperative behaviors in gibbons. Additional behavioral observations revealed that the gibbons spent significantly more time “out of arm’s reach to everyone”, suggesting that they are less often involved in social interactions, than other, more cooperative primates.
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| 2. |
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| 3. |
- Laska, Matthias, 1960-, et al.
(författare)
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Self-anointing behavior in free-ranging spider monkeys (Ateles geoffroyi) in Mexico
- 2007
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Ingår i: Primates. - : Springer Science and Business Media LLC. - 0032-8332 .- 1610-7365. ; 48:2, s. 160-163
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Tidskriftsartikel (refereegranskat)abstract
- During 250 h of observation, a total of 20 episodes of self-anointing, that is, the application of scent-bearing material onto the body, were recorded in a group of free-ranging Mexican spider monkeys (Ateles geoffroyi). The animals used the leaves of three species of plants (Brongniartia alamosana, Fabaceae; Cecropia obtusifolia, Cecropiaceae; and Apium graveolens, Umbelliferae) two of which have not been reported so far in this context in any New World primate species. The findings that only two males displayed self-anointing, that only the sternal and axillary regions of the body were rubbed with the mix of saliva and plant material, and a lack of correlation between the occurrence of self-anointing and time of day, season of the year, ambient temperature or humidity do not fit the hypothesis that this behavior functions in repelling insects and/or mitigating topical skin infections in this species. Rather, the data and the observation that the leaves of all three plant species spread an intensive and aromatic odor when crushed, support the hypothesis that self-anointing in A. geoffroyi may play a role in the context of social communication, possibly for signaling of social status or to increase sexual attractiveness.
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| 4. |
- Motes-Rodrigo, Alba, et al.
(författare)
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Preferential hand use by captive chimpanzees (Pan troglodytes) in manual and tool digging
- 2019
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365. ; 60:4, s. 367-373
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Tidskriftsartikel (refereegranskat)abstract
- Digging for underground storage organs of plants has been reported in various populations of wild chimpanzees (Pan troglodytes). However, it is unknown so far whether chimpanzees display lateral biases in manual digging as direct observations of this behavior are still lacking. It was therefore the aim of the present study to assess, for the first time, hand preferences for digging in a group of nine captive chimpanzees. We found that with only one exception, all individuals engaged in manual digging for buried food. Five individuals displayed a significant right-hand preference, two a significant left-hand preference, and one was ambidextrous. No apparent differences between males and females were found with regard to the direction or strength of hand preferences for manual digging. Only one out of four parent-offspring pairs was congruent in their preferred hand for manual digging. Three of the eight chimpanzees who dug manually also used tools in order to excavate buried food. Among those three individuals, one displayed a significant right-, one a significant left-hand preference, and one was ambidextrous. Only one of these three chimpanzees was consistent in preferring the same hand for manual and tool digging. The present findings are in line with the notion that chimpanzees display significant hand preferences at the individual level for haptic-guided behaviors, with a tendency for the right hand.
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| 5. |
- Norlen, Ellen, et al.
(författare)
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Taste responsiveness of Western chimpanzees (Pan troglodytes verus) to five food-associated saccharides
- 2019
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365. ; 60:1, s. 29-39
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Tidskriftsartikel (refereegranskat)abstract
- Using a two-bottle choice test of short duration, we determined taste preference thresholds for sucrose, fructose, glucose, lactose, and maltose in three Western chimpanzees (Pan troglodytes verus). Further, we assessed relative preferences for these five saccharides when presented at equimolar concentrations and determined taste preference difference thresholds for sucrose, that is, the smallest concentration difference at which the chimpanzees display a preference for one of the two options. We found that the chimpanzees significantly preferred concentrations as low as 20mM sucrose, 40mM fructose, and 80mM glucose, lactose, and maltose over tap water. When given a choice between all binary combinations of these five saccharides presented at equimolar concentrations of 100, 200, and 400mM, respectively, the animals displayed significant preferences for individual saccharides in the following order: sucroseamp;gt;fructoseamp;gt;glucose=maltose=lactose. The taste difference threshold for sucrose, expressed as Weber ratio (I/I), was 0.3 and 0.4, respectively, at reference concentrations of 100 and 200mM. The taste sensitivity of the chimpanzees to the five saccharides falls into the same range found in other primate species. Remarkably, their taste preference thresholds are similar, and with two saccharides even identical, to human taste detection thresholds. The pattern of relative taste preferences displayed by the chimpanzees was similar to that found in platyrrhine primates and to the pattern of relative sweetness as reported by humans. Taken together, the results of the present study are in line with the notion that taste sensitivity for food-associated carbohydrates may correlate positively with phylogenetic relatedness. Further, they support the notion that relative preferences for food-associated carbohydrates, but not taste difference thresholds, may correlate with dietary specialization in primates.
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| 6. |
- Pereira, Sofia, et al.
(författare)
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Taste detection threshold of human (Homo sapiens) subjects and taste preference threshold of black-handed spider monkeys (Ateles geoffroyi) for the sugar substitute isomalt
- 2021
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365. ; 62:2, s. 389-394
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Tidskriftsartikel (refereegranskat)abstract
- The artificial sweetener isomalt is widely used due to its low caloric, non-diabetogenic and non-cariogenic properties. Although the sweetening potency of isomalt has been reported to be lower than that of sucrose, no data on the sensitivity of humans for this polyol are available. Using an up-down, two-alternative forced choice staircase procedure we therefore determined taste detection thresholds for isomalt in human subjects (n = 10; five females and five males) and compared them to taste preference thresholds, determined using a two-bottle preference test of short duration, in a highly frugivorous nonhuman primate, the spider monkey (n = 4; one female, three males). We found that both species detected concentrations of isomalt as low as 20 mM. Both humans and spider monkeys are less sensitive to isomalt than to sucrose, which is consistent with the notion of the former being a low-potency sweetener. The spider monkeys clearly preferred all suprathreshold concentrations tested over water, suggesting that, similar to humans, they perceive isomalt as having a purely sweet taste that is indistinguishable from that of sucrose. As isomalt, like most sweet-tasting polyols, may elicit gastric distress when consumed in large quantities, the present findings may contribute to the choice of appropriate amounts and concentrations of this sweetener when it is employed as a sugar substitute or food additive for human consumption. Similarly, the taste preference threshold values of spider monkeys for isomalt reported here may be useful for determining how much of it should be used when it is employed as a low-caloric sweetener for frugivorous primates kept on a vegetable-based diet, or when medication needs to be administered orally.
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| 7. |
- Persson, Tomas, et al.
(författare)
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Spontaneous cross-species imitation in interaction between chimpanzees and zoo visitors
- 2018
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Ingår i: Primates. - : Springer Science and Business Media LLC. - 0032-8332 .- 1610-7365. ; 59:1, s. 19-29
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Tidskriftsartikel (refereegranskat)abstract
- Imitation is a cornerstone in human development, serving both a cognitive function (e.g. in the acquisition and transmission of skills and knowledge) and a social-communicative function, whereby the imitation of familiar actions serves to maintain social interaction and promote prosociality. In nonhuman primates, this latter function is poorly understood, or even claimed to be absent, yet the evidence is gathered mainly from learning experiments - a context which is less adequate for investigating communicative imitation. In this observational study, we documented interactions between chimpanzees and zoo visitors and found that the two species imitated each other at a similar rate, corresponding to 10% of all produced actions. Imitation appeared to accomplish a social-communicative function, as cross-species interactions that contained imitative actions lasted significantly longer than interactions without imitation. In both species, physical proximity promoted cross-species imitation. Overall, imitative precision was higher among visitors than among chimpanzees, but this difference vanished in proximity contexts, i.e. in the indoor environment. Four of five chimpanzees produced imitations; three of them exhibited comparable imitation rates, despite large individual differences in level of cross-species interactivity. We also found that chimpanzees evidenced imitation recognition, yet only when visitors imitated their actions (as opposed to postures). Imitation recognition was expressed by returned imitation in 36% of the cases, and all four imitating chimpanzees engaged in so-called imitative games. Previously regarded as unique to early human socialization, such games testify to the rewarding nature of imitative interaction and serve to maintain social engagement. Contrary to what it has been suggested, the results presented here indicate that nonhuman apes exhibit spontaneous imitation that can accomplish a communicative function. The study raises a number of novel questions for imitation research and highlights the imitation of familiar behaviors as a relevant – yet thus far understudied - research topic.
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| 8. |
- Robbins, Martha M., et al.
(författare)
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Dispersal and reproductive careers of male mountain gorillas in Bwindi Impenetrable National Park, Uganda
- 2019
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Ingår i: Primates. - : Springer Science and Business Media LLC. - 0032-8332 .- 1610-7365. ; 60:2, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal is a key event in the life of an animal and it influences individual reproductive success. Male mountain gorillas exhibit both philopatry and dispersal, resulting in a mixed one-male and multimale social organization. However, little is known about the relationship between male dispersal or philopatry and reproductive careers in Bwindi mountain gorillas. Here we analyze data spanning from 1993 to 2017 on social groups in Bwindi Impenetrable National Park, Uganda to examine the proportion of males that disperse, age of dispersal, pathways to attaining alpha status, fate of dispersing males and philopatric males, and male tenure length as well as make comparisons of these variables to the Virunga mountain gorilla population. We report previously undocumented cases of dispersal by immature males and old males and we also observed the only known case of a fully mature male immigrating into a breeding group. We used genetic tracking of known individuals to estimate that a minimum of 25% of males that disperse to become solitary males eventually form new groups. No differences were found between the Bwindi and Virunga population in the age of male dispersal, the proportion of males that disperse, the age of alpha male acquisition, and dominance tenure length. The lack of differences may be due to small sample sizes or because the observed ecological variability does not lead to life history differences between the populations. Males in both populations follow variable strategies to attain alpha status leading to the variable one-male and multimale social organization, including dispersal to become solitary and eventually form a group, via group fissioning, usurping another alpha male, or inheriting the alpha position when a previous group leader dies.
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| 9. |
- Sanchez-Solano, Karem G., et al.
(författare)
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Non-visual senses in fruit selection by the mantled howler monkey (Alouatta palliata)
- 2022
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365. ; 63, s. 293-303
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Tidskriftsartikel (refereegranskat)abstract
- There is extensive knowledge about the visual system and the implications of the evolution of trichromatic color vision in howler monkeys (genus Alouatta) related to food selection; however, information about the other sensory systems is limited. In this study we assessed the use of touch, sniffing, and taste in fruit evaluation by 20 adult mantled howler monkeys (Alouatta palliata) on Agaltepec Island, Mexico. During 9 months of observation, we recorded the frequency that each monkey used touch, sniffing, and taste in evaluating cryptic fruits (that remain green during their ripening process) and conspicuous fruits (with red, yellow, or orange colorations when they are ripe). Sucrose content and hardness measurements were made to establish the degree of ripeness of the fruits. We found that mantled howler monkeys used long behavioral sequences during conspicuous fruit investigations. Sniffing was used infrequently, but significantly more often in the evaluation of conspicuous-ripe and unripe fruits compared to cryptic-ripe and unripe fruits. During the evaluation of cryptic-ripe fruits, mantled howler monkeys increased the use of touch compared to evaluating cryptic-unripe fruits. We did not find significant differences in the use of taste in the evaluation of cryptic and conspicuous fruits (both ripe and unripe). Our results suggest that the non-visual senses play an essential role in fruit selection by howler monkeys, with differences in the behavioral strategy according to the fruits conspicuity. The multimodal signals of ripe and unripe fruits allow the howler monkeys to assess their palatability before being consumed.
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| 10. |
- Silveira, Pamela, et al.
(författare)
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Food preferences and nutrient composition in captive Southern brown howler monkeys, Alouatta guariba clamitans
- 2024
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Ingår i: Primates. - : SPRINGER JAPAN KK. - 0032-8332 .- 1610-7365.
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Tidskriftsartikel (refereegranskat)abstract
- Studies of food preferences in captive primates have so far mainly been restricted to frugivorous species. It was therefore the aim of the present study to assess the occurrence of spontaneous food preferences in a mainly folivorous primate, the captive Southern brown howler monkey, and to analyze whether these preferences correlate with nutrient composition. Using a two-alternative choice test, we presented ten male and five female adult Alouatta guariba clamitans with all possible binary combinations of ten types of food that are part of their diet in captivity and recorded their choice behavior. We found the howler monkeys to display the following rank order of preference: banana > mango > watermelon > papaya > beetroot > apple > pear > orange > cucumber > tomato. This preference ranking significantly and positively correlated with the total carbohydrate content and with the sucrose content of the food items. We also found significant positive correlations between the food preference ranking and the content of the minerals copper and magnesium. Male and female howler monkeys did not differ significantly in their food preference rankings. These results suggest this howler monkeys under human care are not opportunistic, but selective feeders with regard to maximizing their net gain of energy as only the content of carbohydrates, but not the contents of total energy, proteins, or lipids significantly correlated with the displayed food preferences. Thus, the food preferences of this primate are similar to those reported in several species of frugivorous primates tested with cultivated fruits and vegetables.
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