We conducted a 15-year troop-based management study of Japanese macaques (Macaca fuscata) in Sendai, Miyagi Prefecture, Northern Japan. Our goal was to maintain an isolated macaque population in this region, and to decrease the level of their crop damage. We classified subject troops (n = 18) into:1) Village-Group (n = 6), whose home range was located near crop fields and caused severe crop damage; and 2) Mountain-Group (n = 12), whose home range was primarily located in a forest with relatively light crop damage. During the study period, we mainly captured Village-Group animals, and drove away Mountain-Groups from the crop field. We also conducted an annual population census from 2003-2017. Over our study period, the number of Village-Group and the total amount of crop damage by the macaques decreased, and we have maintained the total number of animals in Sendai at a constant level of 500-550 animals. In the Village-Group, the decrease in troop members depended on whether the crop field was being used as a feeding site. Therefore, we need to continue monitoring their behavior to decrease crop damage. We found that troop-based management is a useful technique in the Tohoku area where macaque populations are isolated due to previous over-hunting, and researchers need to consider both damage-management and population-management in their studies.
Crop damage caused by wild Japanese macaques (Macaca fuscata) has been a chronic problem in Kochi Prefecture, western Japan. However, the prefecture has not established a specific management plan for the macaques so far, and each town independently conducts its own countermeasures without a clear objective. I attempted to collect information on the present distribution and dietary habits of the macaques in order to draw up a more effective countermeasure plan to reduce the crop damage. I conducted interview survey about crop-raiding by the macacues and their appearance time to grasp the current distribution and status of the macaques. Based on a discretionary criteria, number of troops was estimated to be 74, and they distributed across the entire prefecture, except for Geisei village. Each troop was composed of 10-30 animals. Troop density was high at 1) mountainous forests in the northern part of the prefecture, and 2) coastal part of Muroto and Hata areas, where home ranges of several troops sometimes overlapped. I also conducted stomach content analyses from captured animals to study their dietary habits. I found that the macaques in Kochi prefecture depended on crops throughout year, while they fed also on natural items in fall. In summary, the present crop damage caused by macaques in the prefecture is fairly light, and therefore performing the basic countermeasure (such as driving them away and setting up fences around crops) should be effective. In areas where the degree of macaque dependence on the cultivated crops is high, on the other hand, we need to capture them. For developing effective countermeasure plans in western Japan, in which information on crop-raiding by macaques has been lacking, each prefecture needs to cooperate more closely to accumulate fundamental information on this matter.
Both general and academic attention toward animal welfare has been increasing and the importance of scientific investigation into welfare states of captive animals is being recognized. One of the big questions in scientific studies of animal welfare is how we can assess animal welfare in an objective manner, and this is an intensively debated topic. In this paper, I reviewed the studies on captive chimpanzees (Pan troglodytes) in order to discuss the methodologies used to assess welfare states and introduce studies that have investigated how social environments affect chimpanzee welfare by combining behavioral and hair cortisol (HC) measurements. Recently, cortisol accumulated in the hair of animals has been considered as an indicator of the long-term hypothalamus-pituitary-adrenal (HPA) axis. From a welfare perspective, long-term stress is more problematic than acute stress as it is challenging for animals to experience distress over a long period and long-term activation of the HPA axis can result in overall health deterioration. A series of studies on captive chimpanzees show that HC is useful for monitoring the long-term stress levels in captive chimpanzees. Furthermore, using the novel measure of long-term stress, I found that the stress level of male chimpanzees is affected by social variables and that male chimpanzees use social play as a means to reduce social tension. Although scientific investigation of animal welfare is still not a prevalent practice in Japan, it is a promising area of study both for improving animal welfare and deepening our understanding about animals.
Human speech and vocal communication of nonhuman primates share many features in semantic ability such as referentiality of calls or pragmatic inference. By contrast, a large gap is found in the phonological ability; vocal learning or volitional vocal control are hardly observed in nonhuman primates. However, recent studies have shown similarity between speech and the vocal, facial communication of nonhuman primates used in low-arousal situations. Here I focused on such vocalizations, called contact calls and close calls. These vocalizations are widely seen among primate taxa. Contact calls function to keep group cohesiveness. Close calls are soft vocalizations used in face-to-face communication and function to signal the benign intent of the caller. These vocalizations exhibit the subcomponent abilities that enables human speech as follows. First, they show some plasticity in usage and acoustic features. The use of close calls becomes partner-specific as individuals mature, and this process is influenced by other group members. The acoustic features of contact calls are modified not only developmentally through interactions with parents but also temporally during vocal exchanges. Second, just as turn-taking in human conversation, timing adjustment has been found in both contact calls and close calls, indicating a vocal coordination ability in nonhuman primates. Third, the facial movements of close calls or lip-smacking have been revealed to be putative precursors of speech rhythm. Finally, some studies have shown that monkeys can acquire volitional vocal control through training. Although primates lack direct projection from the cortex to the vocal control region in the brainstem, initiation of such vocal utterance or lip-smacking involves similar brain areas as in human speech. Further investigation of vocal control during contact and close calls in social, natural settings as well as in experimental settings, would contribute to a better understanding of the evolutionary course leading to speech.