Specific mating behavior of Malayan pangolin (Manis javanica) in captivity.

Pangolin is a mysterious animal in the Family Pholidota, Mammalia. Malayan pangolin (Manis javanica) is one of eight existing species and is listed in Manis. With the number of wild pangolins (Manis spp.) rapidly decreasing, captive breeding has become an important way to protect them from extinction. The research on mating behavior of pangolins is an important content to understand its reproductive characteristics and develop breeding management. From 2016 to 2022, a total of 360 mating events were observed in six males and 24 females through closed circuit television (CCTV) surveillance. The results show that males do not engage in complex courtship behavior before mating. In addition, we found that male pangolins adopted a ventrolateral mating position. Once males selected the side (left/right) of the female pangolin from which to approach to mate, they usually remained on the same side for subsequent mating, suggesting that male pangolins may have a preference in mating position. Finally, all mating events were observed at 1.72 ± 1.47 (n = 83, Mean ± SD) days after cohabitation and adjustment time before mating (from the male touching the female to intromission) took 4.98 ± 3.86 mins (n = 323). During mating, males hugged females and remained still for 47.37 ± 10.08 seconds (n = 323), which is the ejaculation and post-ejaculation quiescent time. Remarkably, we observed for the first time two peak mating times, 19:00 to 22:00 and 1:00 to 3:00, suggesting that they may have a preference for mating times. This study provides new insight into the mating behavior of M. javanica and contributes to the development of scientific conservation measures to improve the reproductive capacity of M. javanica.

High-Quality Genomes of Pangolins: Insights into the Molecular Basis of Scale Formation and Adaption to Myrmecophagous Diet.

Pangolins are one of nature's most fascinating species being scales covered and myrmecophagous diet, yet relatively little is known about the molecular basis. Here, we combine the multi-omics, evolution, and fundamental proteins feature analysis of both Chinese and Malayan pangolins, highlighting the molecular mechanism of both myrmecophagous diet and scale formation, representing a fascinating evolutionary strategy to occupy the unique ecological niches. In contrast to conserved organization of epidermal differentiation complex, pangolin has undergone large scale variation and gene loss events causing expression pattern and function conversion that contribute to cornified epithelium structures on stomach to adapt myrmecophagous diet. Our assemblies also enable us to discover large copies number of high glycine-tyrosine keratin-associated proteins (HGT-KRTAPs). In addition, highly homogenized tandem array, amino content, and the specific expression pattern further validate the strong connection between the molecular mechanism of scale hardness and HGT-KRTAPs.

Weaning period and growth patterns of captive Sunda pangolin (Manis javanica) cubs.

This study tracked and recorded the weight changes of 13 captive Sunda pangolin cubs from lactation to maturity to explored the appropriate weaning time and reveal the rules of its weight growth. SPSS 25.0 was used to build a cubic equation model to fit the body weight change rules of 4 individuals who nonvoluntarily ingested artificial feed (NIAF) at 127 days after birth and 5 individuals who voluntarily ingested artificial feed (VIAF) at 86-108 days after birth. The body weight of NIAF cubs aged 0-120 days and VIAF cubs aged 0-150 days were estimated according to the fitting model. An independent sample T-test was performed on the mean body weight of the two groups during the late lactation period. The results showed that at 105 days after birth, the body weight of the VIAF group was significantly higher than that of the NIAF group (P = 0.049), and the body weight of the VIAF group was extremely significantly higher than that of the NIAF group at 114 days (P = 0.008); The peak cumulative body weight of the NIAF cubs during lactation appeared around 130 days of age (n = 3); The mortality rate was 66.7% (n = 3) after about 150 days if the feed was continuously consumed nonvoluntarily. It was concluded that the milk secretion period of the mother is about 0-5 months after giving birth; the weaning period of the cubs should be 4-5 months after birth. If the cubs don't follow the mother to eat artificial feed for 3 months after birth, it can start be induced with artificial diet which adds termites, and the time point cannot be later than 130 days, otherwise it is not conducive to the survival of the cubs; When sexually mature, the body length and body weight of female cubs account for about 84% and 60% of the adult, respectively; the body maturity and body weight of female cubs tend to be stable about 15.3 months and 16.4 months, respectively. Finally, a special needle-shaped nipples and nursing patterns of female Sunda pangolins were also recorded in this study. These findings play an important role in guiding the nursing of captive Sunda pangolin cubs and other pangolin cubs. It is expected to improve the survival rate of the cubs by exploring the appropriate weaning time and the rules of weight growth. By scientifically planning the reproductive cycle of the female Sunda pangolins, our goal is to expand the population size and eventually release to the wild, meanwhile improving knowledge of this critically endangered species.

Successful captive breeding of a Malayan pangolin population to the third filial generation.

Pangolins are threatened placental mammals distributed in Africa and Asia. Many efforts have been undertaken in the last century to maintain pangolins in captivity, but only a few of them succeeded in maintaining and keeping this species in a controlled environment. This study reports the first systematic breeding of the Critically Endangered Malayan pangolin (Manis javanica) in captivity. Our captive breeding approach successfully improved the reproductive rate for both wild and captive-born female pangolins. From 2016 to 2020, we had 33 wild pangolins and produced 49 captive-born offspring spanning three filial generations. The female offspring further bred 18 offspring, of which 14 (78%) were conceived during the first time of cohabitation with males, and four offspring were conceived during the second cohabitation event, suggesting that they may practice copulation-induced ovulation. We observed that captive-born female pangolins could reach sexual maturity at 7-9 months (n = 4), and male pangolins could mate and successfully fertilise females at nine months age (n = 1). We also observed a female pangolin conceiving on the eighth day after parturition (the fifth day after the death of its pup). Our captive pangolins had a female-biased sex ratio of 1:0.5 at birth, unlike other known captive-born mammals. Also, captive-born pangolins were generally more viable after successful weaning and had a similar gestation length (~185 days) to wild pangolins. Most importantly, we report the first self-sustaining captive population of Malayan pangolins, and this species has an efficient reproduction strategy. These advances provide more comprehensive information for people to understand pangolins, and have implications for conserving endangered Malayan pangolins and providing scientific guidance to the management of other pangolin species.

Effects of Chronic Stress on the Fecal Microbiome of Malayan Pangolins (Manis javanica) Rescued from the Illegal Wildlife Trade.

Pangolins (scaly anteaters, Pholidota) are among those mammals that are most affected by the international, illegal wildlife trade. Recently, wildlife rescue centers in China became dedicated to rehabilitate confiscated pangolins and prepare them for reintroduction to the wild. Chronic stress is thought to be the main reason for a disturbed microbiota community and a higher mortality rate of pangolin in captivity. In this study, we compared the cortisol levels and the fecal microbiome of Malayan pangolin (Manis javanica) born and reared in captivity (PCB; n = 7) with those rescued from the wildlife trade (PCT; n = 16). Results show that the level of cortisol in PCT was significantly lower than that observed in PCB. There were also significant differences in the composition of the fecal microflora between the two groups, and the diversity of intestinal microbiota was higher in PCB than in PCT. At the phylum level, the bacteria with significant difference between the two groups included Firmicutes and Bacteroides. At the genus level, bacteria such as Bacteroides, Parabacterides, and Clostridium showed significant differences between the two groups. This study proves that chronic stress has a considerable effect on the diversity and composition of fecal microbiota in Malayan pangolin.