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Chimpanzees are not the only great apes to develop tools without tutoring. Chimpanzees are not the only great apes to develop tools without tutoring., Author Affiliations: A Sumatran orangutan named Padana raps nuts with a log 'hammer' atop a tree stump 'anvil', a technique she invented herself. Credit: Claudio Tennie Padana the orangutan cracking [...]

Wild bearded capuchins (Cebus libidinosus, quadrupedal, medium-sized monkeys) crack nuts using large stones. We examined the kinematics and energetics of the nut-cracking action of two adult males and two adult females. From a bipedal stance, the monkeys raised a heavy hammer stone (1.46 and 1.32 kg, from 33 to 77% of their body weight) to an average height of 0.33 m, 60% of body length. Then, they rapidly lowered the stone by flexing the lower extremities and the trunk until the stone contacted the nut. A hit consisting of an upward phase and a downward phase averaged 0.74 s in duration. The upward phase lasted 69% of hit duration. All subjects added discernable energy to the stone in the downward phase. The monkeys exhibited individualized kinematic strategies, similar to those of human weight lifters. Capuchins illustrate that human-like bipedal stance and large body size are unnecessary to break tough objects from a bipedal position. The phenomenon of bipedal nut-cracking by capuchins provides a new comparative reference point for discussions of percussive tool use and bipedality in primates. KEY WORDS tool use; percussion; upright stance; nonhuman primate

Nut cracking is restricted to communities of wild chimpanzees living in West Africa, suggesting it is an example of a socially transmitted tradition. Detailed study of the acquisition of nut cracking in wild chimpanzees is consistent with this conclusion. However. only 2. small-scale experiments have been carried out in captivity to explore the role of social transmission in the acquisition of this behavior. The study presented here does this with a comparatively larger, statistically viable sample of 11 sanctuaryliving chimpanzees (Pan troglodytes schweinfurthii), permitting both between- and within-subjects experimental manipulations. Results confirmed that nut cracking can be acquired in a matter of days by social learning, but only in chimpanzees 3 to 4 years old and older. Direct comparisons are made with a study carried out in the wild, revealing striking similarities in developmental profiles. Keywords: tool use, social learning, nut cracking, chimpanzees

Primates' understanding of tool functionality has been investigated extensively using a paradigm in which subjects are presented with a tool that they must use m obtain an out-of-reach reward. Alter being given experience on an initial problem, monkeys can transfer their skill to tools of different shapes while ignoring irrelevant tool changes (e.g., color). In contrast, monkeys without initial training perform poorly on the same tasks. Compared to most monkeys, great apes show a clear propensity for tool using and may not require as much experience to succeed on tool functionality tasks. We investigated this question by presenting 171 apes (Pan troglodytes, Pan paniscus, Gorilla gorilla, and Pongo pygmaeus) with several tool-use problems without giving them initial training or familiarizing them with the test materials. Apes succeeded without experience, but only on problems based on basic properties such as the reward being supported by an object. However, only minimal experience was sufficient to allow them to quickly improve their performance on more complex problems in which the reward was not in contact with the tool. Keywords: tool use, tool properties, object choice task, problem solving, causal knowledge

Researchers have investigated animals' causal knowledge with a task requiring subjects to use a tool to bring a reward within reach whilst avoiding a trap. Previous studies have suggested limitations in the ability of several species to avoid traps in tubes or tables. However, certain features may have inflated task difficulty. We tested 20 chimpanzees (Pan troglodytes), 7 orangutans (Pongo pygmaeus), 5 bonobos (Pan paniscus), and 5 gorillas (Gorilla gorilla) in the trap-table--a task in which subjects have to pull one of two rakes prepositioned behind two rewards on a flat surface. One of the rewards is in front of a trap into which it will fall. We investigated the effect of trap type, tool type, the number of available tools, and reinforcement regime on performance. We replicated previous findings showing that apes failed to choose the correct rake above chance. However, when they could instead choose where to insert a single tool, around 80% of the apes solved the trap-table task in the first trial, revealing an important effect of task constraints on their performance. Keywords: tool-use, problem solving, inhibition, primates, causal knowledge

Data from the first systematic study of stone handling (SH) behavior in a captive troop of Japanese Macaques that were known to exhibit the behavior is presented. Age-related differences in SH performance and behavioral patterns were seen showing possible differences in the immediate cause and ultimate functions between young and adults.

The surveys of long tailed macaques at Piak Nam Yai Island, Laem Son National Park, Ranong Province, situated in Southern Thailand have observed that they use axe-shaped stones to crack rock oysters, detached gastropods, bivalves, and swimming crabs. The tool usage by Thai long-tailed macaques that crack rock oysters with stones could be characterized as level 1, and that cracking drifting mollusks and crabs with stones by placing them on rock could be characterized as level 2.

The authors examined how 2 lemur species (Eulemur fulvus and Lemur catta) reason about tools. Experiment 1 allowed subjects to use 1 of 2 canes to retrieve an inaccessible food reward. Lemurs learned to solve this problem as quickly as other primates. Experiment 2 then presented subjects with novel tools differing from the originals along one featural dimension. Subjects attended more to tools' sizes than to their colors and made no distinction between tools' shapes and textures. Experiments 3 and 4 presented problems in which some of the tools' orientations had to be modified relative to the food. Subjects performed well on these problems, sometimes modifying the position of the tool. These results are discussed in light of the performance of other primates on this task.

Cottontop tamarin subadults with only minimal experimental experiences, and no experience with tools or tool-like tasks are tested and also subadult common marmosets Callithrix jacchus is tested. Results indicate that in the absence of any experience, neither tamarins nor marmosets are able to discriminate between functionally relevant and irrelevant features of a tool.

Research into the cognitive behaviour of Asian elephants investigates the use and modification of branches for fly switching.

Rodent wheel running is a useful tool as an operant that produces access to food, for studies associated with a variety of parameters such as feeding and time of day, and as a schedule-induced and competing behavior. A series of experiments on rats was conducted to augment recently established methods for wheel-running reinforcement. The results support the recommendation that self-paced responding may improve the reinforcing effect of reinforcers that are presumably weak because deprivation cannot be done or is ineffective.

Chimpanzees and capuchins demonstrate greater varieties and higher rates of tool-use when compared to other non-human primates. Although capuchins have been studied extensively in captivity, data on their tool-using behavior under free-ranging conditions are limited. This is the first long-term field research to systematically study complex object manipulation in capuchins. The aims of this research are 1) to examine the types, rates, and contexts of tool- and object-use in free-ranging capuchins and 2) to determine if free-ranging capuchins' object manipulation behavior is comparable to the behavior exhibited by captive individuals. Data on 3 troops of white-faced capuchins (Cebus capucinus) were collected from February 1995 to January 1996 at Palo Verde, Costa Rica. Data were collected using focal animal and ad libitum sampling techniques. Any observed incident of tool-use and object-use was recorded. No tool-use was observed during the 11-month study. Object-use (pound, rub, and fulcrum-use) occurred at a rate of 0.19/hr and made up less than 1% of the monkeys' time (there were no differences among the age/sex classes). The results indicate that free-ranging capuchins do not exhibit the range of tool-using behavior demonstrated by their captive counterparts. This may be the result of differential motivational responses to objects, arboreal lifestyle, absence of adequate tool material, and/or absence of food resources that require extraction involving tool-use. KEY WORDS primates; tool-use; object manipulation; extractive foraging

Tufted capuchins (Cebus apella) were provided with a task that facilitated the use and modification of sticks as probing tools. It was found that subjects aged 10 years or older at initial task exposure were less likely to use tools than were younger subjects. Furthermore, juveniles whose mothers died before the subjects were aged 3 years were less likely to use tools than were juveniles whose mothers survived through this period. The ability to use tools was not related to subject sex or to access to the tool site or raw tool materials. Subjects modified tools both before and during their use, and the relative percentage of tools modified increased with subject age. Thus, it appears that capuchins most readily acquire tool use before the age of 10 years and that early disruption of the mother-infant relationship has deleterious effects on the emergence of instrumental behavior.

Scientists studying wild orangutans in swampy Sumatra have discovered that the red apes in the region make tools for use in the wild. Previously, the only primate besides humans to make tools in the wild had been known to be chimps, although other primates have used them in captivity. The red apes were observed to construct a variety of tools for foraging, with individual tools for tasks, including many for getting fruit or honey. Each tool would be modified until it perfectly suited the job at hand. Scientists suspect that orangutans have used tools in certain geographical locations only to cease doing so later on.

Performance by individual animals of three species of great apes (Pan troglodytes, Pan paniscus, and Pongo pygmaeus) and capuchin monkeys (Cebus apella) was assessed by presenting a food treat inside a clear tube. The subjects readily used a straight stick to obtain the food. When sticks were bundled together, the apes immediately unwrapped the bundle to obtain an individual stick, whereas capuchins attempted to insert the bundled sticks. When a misshapen stick was provided, apes, but not capuchins, showed an improvement in terms of modifying the misshapen stick before insertion. Our results indicate that all these species can solve these tasks. However, only the performance of apes is consistent with emerging comprehension of the causal relations required for the avoidance of errors in the more complex tasks.

Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a tool task. The task consisted of a transparent tube with a trap-hole drilled in its middle. A reward was randomly placed on either side of the hole. Depending on which side the chimpanzee inserted the stick into, the candy was either pushed out of the tube or into the trap. In Experiment 1, the success rate of 2 chimpanzees rose highly above chance, but that of the other subjects did not. Results show that the 2 successful chimpanzees selected the correct side for insertion beforehand. Experiment 2 ruled out the possibility that their success was due to a distance-based associative rule, and the results favor an alternative hypothesis that relates success to an understanding of the causal relation between the tool-using action and its outcome.

A microchip that provided a unique identification number was injected into each forearm of all 8 members of a bonnet macaque (Macaca radiata) social group. The group was then given computer-controlled joystick tasks of increasing difficulty. The identification number of the arm used on each trial was input into the computer and used to determine individual performance and hand preference in more than 23,000 trials. Three subjects reversed hand preference as task difficulty was increased over time. All subjects exhibited nearly exclusive use of a single hand on the most difficult task; 6 used the right hand, and 2 used the left. Daily patterns of joystick activity for the group members differed somewhat from that of our individually housed monkeys.

Common chimpanzees (Pan troglodytes) and 2-year-old human children (Homo sapiens) were presented with a rakelike tool and a desirable but out-of-reach object. One group of subjects observed a human demonstrator use the tool in one way, and another group observed a demonstrator use the tool in another way. Children in both cases did what the model did. Chimpanzee subjects, however, behaved identically in the 2 model conditions. Both groups performed better than subjects who saw no demonstration. This pattern of results suggests that the chimpanzees were paying attention to the general functional relations in the task and to the results obtained by the demonstrator but not to the actual methods of tool use demonstrated. Human children were focused on the demonstrator's actual methods of tool use (her behavior). The different social learning processes used by the 2 species have implications for their different forms of social organization.

Hand preference in the use of tools was examined in a peer group of five infant baboons, Papio cynocephalus anubis. Hand preference was noted for all subjects on a sponging task and for one subject on a probing task. The baboons exhibited the highest percentage of bimanual actions on the initial segment of each three-component task. These results are consistent with the hypothesis that immature nonhuman primates exhibit lateral asymmetries when they use tools and bimanual coordination when they perform complex manipulative tasks.

In the 'video-task paradigm' a subject manipulates a joy-stick to move a cursor into an experimenter-defined target area on a computer monitor, generally receiving a food reward upon completion of the task. Despite the spatial separation of the joy-stick, monitor, and location of reward delivery, the video-task paradigm has been successfully implemented with several macaque species and with chimpanzees. Preliminary attempts to implement the paradigm with squirrel monkeys, however, were not successful. This report describes successful performance by a squirrel monkey in the paradigm. After learning to move the cursor to contact a small target randomly appearing at four screen locations, the monkey was readily able to move the cursor to contact a moving target in novel locations on the monitor screen.

Hand preferences of two Japanese macaques were observed in five differing tasks: simple reaching for food on a platform; choosing of boxes with pieces of apple; mirror-guided reaching (taking food from the box, key pressing, key tracking). Though these were visually guided tasks, the macaques showed different hand preferences.

The purpose of this study was to examine hand preference in the use and manufacture of probing tools by tufted capuchin and lion-tailed macaque monkeys (Cebus apella and Macaca silenus). Hand preference for the tool-using sequence was noted in 4 of 5 capuchins (a left-hand preference was noted in 3 ss) and 3 of 4 macaques (a left-hand preference was noted in 2 ss). The monkeys frequently used bimanual action in the initial and final segments of the 3-component task and typically modified tools through coordinated action of the hands and teeth. These data provide evidence consistent with the hypotheses that (a) hemisphere specialization for manual control evolved in primates prior to intensive use of tools by early hominids and (b) monkeys prefer the left hand for precise, visually guided, manipulative actions.

New Caledonian crows were observed from Nov. 1992 to Mar. 1995 to study their tool behavior. Results belie the existing claim that tool behavior in wild birds is mostly stereotyped and tool manufacture is virtually nil. The New Caledonian crows used and manufactured two different types of hook tool for predation purposes, namely, hooked-twig and stepped-cut pandanus leaf. Tool manufacture among crows exhibited features alien to tool use in wild nonhuman animals, namely, a high degree of standardization, distinctly discrete tool types distinguishable through shape, and the use of hooks.

Several studies are conducted to determine size, weight, structure and other physical properties of the palm fruits that are processed with tools by wild bearded capuchins (Cebus libidinosus) living in Boa Vista. The peak-force-at-failure of these trees is shown to be positively related to greater weight and structural complexity.

The article explains the invention and modification of the 'ant-fishing' behavior, which is used as a tool use behavior by the wild chimpanzees at Bossou, Guinea. The accumulation of the behavior at the site is also studied.

The observation from 3-year ecological study on Cross River gorillas at the Kagwene Mountain in Cameroon about three cases of tool use is reported. The observations were identified as a unique behavior in the gorillas learned through interactions with humans and as a response to particular local conditions.

The effects of inheritance and individual learning on twig tool usage of New Caledonian crows are presented.

An experiment is conducted to examine the effect of substrate on the nut-cracking behavior of a group of semicaptive capuchin monkeys (Cebus apella). The results have shown that adult capuchins chose the hardest substrates, and that these substrates have supported efficient cracking.

The first observation of tool use by the chimpanzees of the Ngogo, community of Kibale National Park, Ugana, in insect foraging is reported. The importance of this observation, and the behavioral similarities with chimpanzees from other sites is discussed.

A detailed description of the different types of chimpanzee tools is provided found during a 7-month survey of the Ngotto Forest to the south of the village of Grima and the tools with types found at other sites were compared. It was expected that the chimpanzees would construct stick tools of different lengths depending on whether they were using them for honey-probing or ant-dipping.

Brown capuchins (Cebus apella) at Raleighvallen Nature Preserve in Suriname have recently been discovered to exhibit object manipulation abilities in foraging, specifically frequent substrate use and a remarkable episode of tool use. The food items being processed with these exceptional skills are numerous species of morphologically diverse, thickly husked fruits, with fruit walls impenetrable even to the powerful jaws of C. apella. These fruit taxa, many in the Lecythidaceae, the Brazil nut family, are rare in Western Amazonia and Central America, regions in which capuchins have been most often studied. Based on extensive qualitative observations, we provide a preliminary description of this phenomenon within a natural history perspective. The manipulative skills of brown capuchins in Suriname are poised to upheave current understandings of tool use and object manipulation in capuchins. Moreover, the implications of these findings for the cognitive evolution of human and nonhuman primates are significant. The capacity to use tools is considered one of the major achievements of our species and figures deeply in explanations for the origin of human intelligence and behavior. Many hold that tool and object manipulation, language, social skills, and morphology are linked in primate evolution. Given that unusually complex social and communication skills are not evident in capuchins, the proposed connection between the evolution of tool use, language, and social skills in human evolution is thereby weakened. Instead, our observations in Suriname support a paradigm premised on the concept of functionally and evolutionarily distinct brain modules. [tool use, evolution of intelligence, cognitive domain, chimpanzees, seed predation]

The authors investigated the occurrence of naive chimpanzees' (Pan troglodytes) spontaneous observation of experienced conspecifics during a tool-use task entailing honey fishing. The chimpanzees were presented with 20 kinds of 'tools' of which 12 kinds were usable. Six pairs of naive and experienced chimpanzees were brought to this honey-fishing situation. A total of 40 observation episodes occurred between the naive and experienced groups, 34 of which were from naive toward experienced individuals. Naive chimpanzees never observed their partners after their own success but did so after their own failure or before their first attempts. In addition, there were 10 cases in which naive individuals used the left-over tools of the experienced ones. Two factors for the transmission of tool use were clearly evident in this study: (a) spontaneous observation of an appropriate behavioral sequence and (b) enhanced environmental cues made by skilled individuals.

To identify behaviors related to acquisition of tool-use in tufted capuchins (Cebus apellag), we presented two tool-using tasks to two groups, extending findings by Westergaard and Fragaszy (1987) and Visalberghi (in press). Five Ss learned to use the tools in each task. The primary predictor of success was level of interest in the task. Observation of others at the apparatus did not facilitate exploratory behaviors or contact with the tools in the observers. Most animals performed exploratory behaviors more often when they were at the apparatus alone than when with another, whether or not the other was using a tool. Observers were quick to learn the relationship between another's activities and the appearance of food. We conclude that capuchins do not readily learn about instrumental relations by observation of others or imitate other's acts. Imitation probably plays no role in the spread of novel instrumental behaviors among monkeys.

Tool use and manufacture among humans have been taken to connote culture. Although tool use was first observed among the Homo habilis, standardization and sophistication arose among Home erectus. In free-living animals, only chimpanzees have so far exhibited standardization of their tools. Recently, however, the discovery of tools used by New Caledonian wild crows revealed that birds, like humans and chimpanzees, are also capable of tool manufacture. However, a standardized tool manufacture can only be a hallmark of culture if the tool has been modified prior, not after, to usage.