202406/11
On July 20, 2023, a Chinese Moccasin (Deinagkistrodon acutus) (also known as sharp-nosed pit viper or hundred-pace viper) was discovered at the Basianshan Forest Recreation Area by the environmental education instructors from the Nature Education Center of the Taichung Branch, Forestry and Nature Conservation Agency (FANCA), as well as the children participating in the summer camp. When instructor Huei Ai-Ling found the snake again in a cave a week later, it was already nesting snugly over a clutch of eggs. The FANCA Taichung Branch Director Chang Hung-Yi immediately arranged for a fence to be set up at the scene. He also commissioned the Formosan Wild Sound Conservation Science Center to set up surveillance camera facilities. This resulted in a complete record of the process of this Chinese Moccasin guarding its eggs and young until the juvenile snakes left the nest. At the press conference on June 11, the FANCA presented the world's first video footage on the reproductive ecology of a wild Chinese Moccasin.[F1]
According to the FANCA, the Chinese Moccasin (Viperidae) is a pit viper native to Taiwan and falls under the category of “Rare and Valuable Species” of Protected Wildlife. Looking at documented references, many pit vipers have been recorded to show egg-guarding behavior, but most of the recorded observations were only of females curled up over their eggs in the wild or in a captive environment. After discovering the eggs laid by this particular wild Chinese Moccasin, the FANCA Taichung Branch actively utilized a variety of filming techniques to record the whole process, and even invested manpower to guard the eggs 24 hours a day. It was all of these efforts that made it possible to obtain such valuable information and images.
Chang Hung-Yi, Director of the FANCA Taichung Branch, said that this was the first time in Taiwan and in the world that the complete process and behaviors of the Chinese Moccasin after laying eggs in the wild have been fully recorded: from egg-guarding, hatching, young protection, to the juvenile snakes’ departure from their nest. The FANCA Taichung Branch also collaborated with the Formosan Wild Sound team to use an automated infrared camera in conjunction with other tech equipment, including a time-lapse camera, night-vision goggles, and BWV cameras. After filming day and night for more than two months, the team succeeded in recording the hatching of the entire clutch of 20 eggs and the safe departure of all of the juveniles. Using harmonic radar tags that do not affect the activities of the young snakes, they were able to successfully track their movements after they left the nest, which is a major breakthrough in the global research on the tracking of juvenile snakes.
The FANCA Taichung Branch added that it also observed the female snake guarding her eggs, as well as possible temperature regulation behavior to facilitate the hatching of the eggs by leaving the nest for a period of time at noon and returning to the nest, and the female snake protecting her young by remaining in the nest after their hatching. In addition, it was the first time that harmonic radar tags, a system used in avalanche rescue, was used to track the activity of the young snakes after they left their nest.
Harmonic radar technology have been used in the tracking studies of insects, frogs, and lizards. The Formosan Wild Sound team, in collaboration with National Museum of Natural Science, attached the tags to the bodies of the juveniles, which had completed their first molting after leaving the nest, and carried out tracking on these individuals. The team found that these juveniles did not immediately disperse over long distances after leaving their nest, but instead hid in the nearby rock crevices and bushes, and then gradually moved to the surrounding secondary forests. Activities were most frequent in the early mornings and late afternoons. The FANCA Taichung Branch also explained that after the second molt, all of the tags attached to the snakes’ bodies also fell off, so the devices will not hinder the growth of the young snakes.
At the press conference, Director General of the FANCA Lin Hwa-Ching, who is a former snake researcher, mentioned that he coincidentally set the official record for the first mating and breeding of captive Chinese Moccasins in Taiwan during his tenure at the Taipei Zoo in 2000. Lin Hwa-Ching said that the reproductive behavior of snakes in captivity does not change much in terms of ecology. In the two reproduction records of Chinese Moccasins at the zoo, the eggs were laid in late July and hatched in late August, with an incubation period of over 30 days. This is similar to the FANCA Taichung Branch’s Basianshan case, and the female snake also showed egg-guarding behavior after laying the eggs.
However, compared with the difficulty of observing the initial courtship stage of the Chinese Moccasin in the wild, Lin Hwa-Ching said that from past breeding experiences at the zoo, it was observed that the Chinese Moccasin began courtship in October, with the male softly flicking its tongue and the female holding her head high. After a three-week period of mating, the male and female snakes returned to their solitary lives without any further interaction. From February of the following year, the mated female grew considerably in size until she laid the eggs in late July. Before laying the eggs, the female would not feed for at least eight months. During the process, it was also found that the female snake’s egg guarding behavior was particularly pronounced during the two weeks after egg laying, and she would strongly resist the staff from touching her eggs.
However, Lin Hwa-Ching also pointed out that since it is difficult to maintain a stable temperature and humidity level for eggs to hatch in a captive environment, the eggs had to be moved to an incubator, so it was not possible to observe the female’s egg guarding behavior during the post-hatching period, or key moments such as when the female left the nest or young snakes, and whether or not she protected the hatchlings. Therefore, the Basianshan case has filled the blanks in the reproductive data of the Chinese Moccasin. The integration of the captive breeding at the zoo in 2000 and the observation of the reproduction of a wild individual at Basianshan after a gap of 23 years has completed valuable reproductive ecological data of Taiwan’s native Chinese Moccasin.
The FANCA Taichung Branch said that the Basianshan Forest Recreation Area offers a diverse forest environment, which of course also makes it the habitat of many snakes. Therefore, the FANCA Taichung Branch will incorporate this invaluable case into the lesson plans and environmental education activities of the Basianshan Nature Education Center. The FANCA also reminds the public that snakes are a part of Taiwan’s natural ecosystem and an indicator of ecological health. When people go into nature, they should be safe as long as there are nighttime lights and they avoid exposing their legs and limbs, or reaching into dead wood piles and rock crevices where they cannot see the inside. Snakes in Taiwan do not actively attack people, so even in the event of encountering a snake, do not try to attack or catch the snake; either leave quietly or wait for the snake to leave on its own accord. When you enjoy the beauty of the mountains and forests, remember to also live in harmony with wildlife.