Blood analysis is an important tool for health management. Our zoo succeeded in being the first in the world to train our mandrills (Mandrillus sphinx), to allow venipuncture using only behavioral restraint. Two mandrills at Omuta City Zoo participated in this project, one male (A) and one female (B). We used PVC pipe to create a sleeve that could be attached to the enclosure and set a bar inside of it so that the mandrill would grip it underhanded, thus presenting the inner side of the arm. By partially blocking the top half of the inside of the sleeve, the mandrills were guided to use an underhand grip. This simplified the training, with less stress for both animals and keepers. The needle insertion was done into the cephalic vein. We used sweet potato as the unlearned reinforcer and a dog whistle as the learned reinforcer. The process was as follows: 1) excitatory conditioning, 2) gripping, 3) gripping underhanded, 4) avascularization, 5) epilation, 6) needle insertion. Training was held once a day for an average of 6-11 minutes. Number of sessions and cumulative time were 34 sessions/365 minutes for the A and 65 sessions/392 minutes for the B. The training has retained a high success rate (85% for the A, 79% for the B), allowing for regular blood sampling.

The stump-tailed macaque, Macaca arctoides, is the most distinctive in its genus with respect to reproductive anatomy and sexual behavior. Male-male mounting behaviors have been mentioned in many reports; however, ejaculation has not yet been recorded.
Herein, we report a very rare case of ejaculation in the context of male-male mounting in wild stump-tailed macaques in Khao Krapuk Khao Taomor Non-hunting Area, Thailand. The behavior was observed during documentary filming of the animals. Daily observations were conducted for 28 days from July 4th to 31st, 2018, from 8 am to 6 pm. This rare behavior was documented on July 12th, while following and filming the Wngklm group. A young male of this group, WKM-M33, and a young male of another group (Fourth group), FTH-M33, started mounting. Initially, this mounting seemed to be social interaction in the context of a group encounter. However, after a thrust of a few seconds, the mounter, WKM-M33, exhibited ejaculated-like behavior. The mountee, FTH-M33, exhibited teeth-chattering behavior and touched the mounter's genital area. After completion of the mounting, whitish semen dropped to the ground and was eaten by WKM-M33. Then, WKM-M33 squeezed out sperm from the erect penis and ate it. We were therefore convinced that the mounter, WKM-M33, had ejaculated at the time of mounting.
Although it is dificult to draw a definitive conclusion because it is a single case report, we propose two possible interpretations: 1) accidental case owing to extreme tension from group encounters during social interaction or 2) homosexual behavior between males with little access to females.

We studied wild chimpanzees (Pan troglodytes) in the Ugalla savanna woodland area of Tanzania from 1995 to 2012. Ugalla is the eastern-most chimpanzee habitat and is one of the driest and most open areas. From 52 direct observations of unhabituated chimpanzees, we found 59.6% of parties (temporal sub-groups in a unit-group) in trees and 32.7% on the ground; 59.6% of parties were observed in forests, 38.5% in woodlands, and none in grasslands. The mean±SD party size (excluding infants) was 3.1±2.2 (range 1.10) individuals. Party sizes were smaller in the rainy season (2.0 individuals) than in the dry season (3.6 individuals). This suggests that chimpanzees reduce feeding competition by forming smaller parties, especially in the rainy season when fruit availability is low and/or food patches are small. We found a lone male eight times, whereas we found a lone female only once. Mixed parties contained more females (1.9 individuals) than males (1.4 individuals). Mothers with infants might join a mixed party to reduce predation risk. The size of mixed parties with oestrous female(s) averaged 5.7 individuals, whereas that with no oestrous female averaged 4.0 individuals. We found four consort parties but no all-male party. This suggests that male chimpanzees in Ugalla frequently foraged with oestrous females but did not patrol their territory because their home range is huge and their population density is very low. Chimpanzees in Ugalla changed their party size and composition according to their feeding, anti-predation, and reproductive strategies to adapt to a savanna woodland area.