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Dive in the Air beside a Rice Paddy

A Moment to Grab an Eluding Snake

Since I became a snake researcher nearly 40 years ago, the question I have most frequently been asked is Why are you studying snakes? Of course, my answer is Because I love snakes. Then, the next question is always Why do you love snakes? Truly, I have no idea why I came to love snakes. What I can answer is I was born to love snakes.

I was born in Osaka city. Osaka is the second largest city in Japan, but my hometown was located in a peripheral suburban area, which was just developing as a residential town at that time. Small rice paddy fields were scattered around my house, but there were no nearby woods, river, or swamp where I could easily see reptiles and amphibians. I was not a naturalist when I was a kid. Although I often kept goldfish and many kinds of insects, such as horned beetles, grasshoppers, fireflies, and cicadas as pets, I never kept amphibians or reptiles until I was 18 years old. I was usually playing in my house or in front of my house with my friends or with toys rather than going outside to explore the wild. Nonetheless, I liked animals in general and particularly snakes. I had a large collection of small rubber models of creepy animals: spiders, centipedes, scorpions, lizards, and, of course, snakes. I collected as many kinds of rubber snakes as possible (not so many were manufactured at that time, though). I liked to watch TV programs about nature and animals, and I spent much time reading my favorite color guidebooks and magazines about animals, especially reptiles, over and over again. When I was in my twenties, I found an old notebook deeply hidden on my shelf. In it, I found my childish pencil drawings of long and undulated creatures. Apparently, these depict snakes (I could recognize eyes and opened mouths). I guess those are my drawings at the age of three or four.

My late grandmother told me a long time ago that when I was a kid, a small snake once came into our house through the front door and my family panicked. I have no memory of that. However, I do remember that I sometimes heard snake–rat chasing sounds from above the ceiling of my old wooden house. A light, staccato sound made by a running rat (perhaps Rattus tanezumi) was followed by a low, slithering sound caused by a snake (most likely a Japanese Ratsnake, Elaphe climacophora) chasing the rat.

My first real encounter with a wild snake was probably when I was 9 or 10 years old. As a holiday outdoor activity, my mother had taken me to gather chestnuts in the mountains. When I was alone looking for chestnuts in a shady, small wooded area, I saw a large snake, probably a Japanese Ratsnake, slowly moving on the ground a few meters away from me. The snake apparently did not notice me and continued its slow exploring movements, which I silently watched for a while staying a couple of meters away. After experiencing a short, mysterious, dreamlike time, I quietly left without disturbing the snake. I did not tell my mother or anyone else that I had seen a snake. Somehow, I felt I should not share my first encounter with a wild snake with anyone, instead keeping it as my sacred secret.

The second encounter was my first great snake hunt. When I was in my first year of high school, one of my classmates took me to a rice paddy owned by his family where, he said, there were many snakes. On the mainland of Japan (Honshu), the best place to find snakes is rice paddy fields. Eight species of snakes occur in most areas of Honshu, and all of them can be found in or around paddy fields. The two most common species, Japanese Striped Snake (E. quadrivirgata) and Tiger Keelback (Rhabdophis tigrinus), are easy to find in paddy fields from spring to early summer. They are either basking in front of shelter, such as stone walls beside the paddy, searching for frogs along foot paths, or swimming in the water-filled paddy. The paddy field that my classmate showed me was a great habitat for snakes. I looked at a stone wall where he had often seen snakes … and … there they were! I quickly stretched out my hand to catch one snake after another. Those were adult-sized Japanese Striped Snakes, and they were everywhere. I guess I collected more than 10 snakes within several minutes. My classmate was impressed that I was good at catching snakes, even though it was my first time. We brought them back to the high school and kept them in a large glass cage in a room for the biological experimental class (the classmate belonged to a student biology circle at the high school). That night, I asked my family if I could keep the snakes at home, but they said no. I was easily persuaded to buy and keep two small birds, budgerigars, instead of keeping snakes. Meanwhile, the snakes that were left in the high school room escaped from the cage and disappeared. Neither one of us knew how adept snakes are at escaping from a cage. My classmate was seriously scolded by a teacher who was in charge of the biology circle. Fortunately I was not scolded because I did not belong to that circle. He quit the biology circle after this incident. (I’m sorry about that, my friend.)

My snake-devoted life began when I was an undergraduate student at Kyoto University. There I joined a biology circle called the Wildlife Research Association. I periodically went to the Ashiu Experimental Forest of Kyoto University, where I found plenty of snakes. I read many scientific papers written by Prof. Hajime Fukada, a pioneer in ecological studies of snakes in Japan, to learn field methods and techniques for studying snakes. Then, I started a basic mark-and-recapture study in Ashiu by myself and also began to keep snakes in my house. This time I was clever and skillful enough to persuade my family to allow me to keep snakes at home.

My snake-catching methods have evolved (and improved) over the years. I have learned suitable ways of catching snakes, specific to the species, by watching the behavior of these animals in the field. For example, among the eight species of snakes on Honshu, six species are active during the day. Among them are the two most common species, Japanese Striped Snakes and Tiger Keelbacks, which usually maintain relatively high body temperatures and move swiftly. Whenever I find these snakes, I have to move quickly to catch them. If a snake notices me approaching, it will swiftly move into a nearby bush or shelter. To overcome this escape tactic, I have to dash toward the snake and dive in the air while stretching out my hand as far as possible to grab the fleeing snake, just like an action movie star running and diving away from an explosive bomb. It is the most delightful moment when I can feel the snake’s body in my hand while my body is touching down on the ground.

In the field, I often notice the presence of a nearby snake by hearing a specific sound caused by its slithering rather than by seeing it. In that case, I quickly turn to the sound source, while looking for the sound maker and stretch out my hand to prepare for grabbing a presumed snake. On Honshu, the only dangerous venomous snake is a pit viper, Gloydius blomhoffii (Mamushi). If I identify the sound maker as a Mamushi, I immediately abort hunting before my hand reaches the snake and touches the body. Fortunately, the Mamushi is relatively small and is generally not very aggressive, and I have never been bitten by a Mamushi while hunting snakes. However, caution is necessary when I grab the Tiger Keelback, a rear-fanged natricine. Although this snake is generally calm and does not bite unless molested, its venom is potentially lethal, and several cases of human death by its envenomation have been reported.

The above diving hunt is not a suitable way to catch snakes in areas other than Honshu. On Okinawa Island of the Ryukyu Archipelago, which is located in the subtropical region of Japan, much more caution is necessary because a large pit viper, the Habu (Protobothrops flavoviridis), is common. Similarly, in tropical regions such as Taiwan and Borneo, a quickly escaping snake might be a dangerous cobra.

In this regard, Madagascar is a paradise. About 100 species of snakes are present in Madagascar, but there is no true venomous snake (although many of them are rear-fanged snakes with mild venoms). I have visited a tropical deciduous dry forest, Ampijoroa, in northwestern Madagascar for long-term ecological research, and we have recorded 20 species of snakes. There I can dive without hesitation toward a snake whenever it comes into my sight. However, I soon learned that something different is going on in that environment. If I dove toward the snake immediately when I saw it, I often failed to capture the snake. Because the body temperature of diurnally active snakes is very high in Ampijoroa, they can move quickly. Thus, if I dash toward a snake from a distance, the snake can evade my hand and escape into the bush before I reach it. Strangely, however, if I do not chase a snake, the snake does not escape into nearby bush. Instead, it stops fleeing after a short distance and stays still in an alert posture. If I remain motionless, the snake soon resumes its routine exploring movement. Therefore, I learned the following hunting method. When I find a snake fleeing, I should first freeze and wait until it stops moving. Then, after I visually locate the exact position of the snake, I carefully and very slowly approach the snake until I reach the range within which I can catch it by a short jump. After I started using this technique, the success rate of my hunting became very high.

Why do snakes in Ampijoroa adopt such a fleeing style? I speculate that it is attributable to the high density of animals in this forest. The Ampijoroa forest is not so large, having about 200 km² in area. Nonetheless, this forest provides home to many species of terrestrial vertebrates. We have confirmed 20 species of mammals, 86 species of birds, 55 species of reptiles, and 11 species of frogs—and some of these animals are living in quite high densities. Therefore, a given vertebrate would often encounter another animal, but in most cases the opponent would be a harmless coinhabitant that does not have to be avoided. Under this circumstance, if an animal flees a long distance to hide every time it encounters another animal, it might waste time and energy for unnecessary flight. Thus, natural selection might have favored individuals that make only a short run and determine whether the situation is really a risky one rather than individuals that run far away to a safe area whenever they meet uncertain danger.

There is no rule without exceptions. The exceptions are two relatively small, semifossorial species of Madagascar smooth snakes (Liophidium). They are usually crepuscular and are often found in leaf litter at the edge of small woods. If I use the above freeze-and-sneak hunting technique against these species, I will lose them. These snakes almost always quickly disappear after a short burst of movement; they likely slide under the leaf-litter layer. For these snakes, I use the standard method: dive toward the snake as soon as I find it.

These observations in Ampijoroa are based on my personal experience and must be tested to be scientific evidence. Nonetheless, I am pretty sure that snakes have many different styles of fleeing, which would have been uniquely evolved in different species or under different environmental conditions. This idea would have never occurred to me if I did not go to the field and see wild snakes. Even in a simple behavioral act, such as fleeing, we find unexpected diversity. I am confident that there is more amazing, fantastic diversity of snake behavior that you can discover only when you go to the field and meet wild, active, healthy snakes. Now I can answer that this is one of the reasons why I am attracted to snakes.