Solving Human–Elephant Conflict in Sri Lanka

By Eng. Ruwan Nagahawatte

1.0 Introduction

Sri Lanka is among the top countries in the world that have large bio diversity. But, Industrial development and urbanization in Sri Lanka has threatened many animals that have been living in different regions of the country. Even though many animals that do not have enough muscle and intelligence to fight back against the humans, had been thrown out of their native habitats. However the elephants have been able to fight back for their native habitat and even to challenge human existence in some of areas of the country with their strength and intelligence.

Total elephant population in Sri Lanka is approximately 7500. Country loose 300 elephants per year in average and based on latest statistics, death ratio for human to elephant is almost 3:1. Unfortunately, we are one of nation that had endangered the native elephant population. Below map shows the scale of spread of this problem in the country. So far an effective solution for co-existence has not been found. Hence as an engineering community of this country engineers have paramount responsibility to act swiftly to find a find a suitable tool that keeps elephants in the jungle and help to find a way for coexistence.

Beating drums, making loud human noise, lighting fire, making electric fence, creating trenches, bursting fire crackers are widely used from generations to chase away the elephant from human farmlands but most of them had been ineffective and carry great human risk. The high intelligence levels and adaptive learning capabilities of elephants have been able to create headache for human who they thought that they’re the most intelligent species of this world. Hence it is important to understand the elephants’ needs and capabilities first, before making plan for conservation.

2.0 Understanding the Elephants

2.1 Elephant Behavior

Elephants have played vital part in Sri Lankan history in fighting many wars with our kings and safeguarding the country from enemy forces. Elephant also play a very dominant role in our cultural and religious activities. While much of the people love this majestic giant, it had been a never-ending struggle for many poor farmers to safeguard their crops and to survive against the encroaching elephants. Generally Elephants are non-violent against other species if they were not threaten. The trunk of an elephant is a fusion of the nose and upper lip. It does not contain any bones, but is composed of thousands of muscles, as well as blood vessels, hair, skin, and bristles. The trunk is a highly versatile tool and is used to smell, breathe, touch, lift, grasp, feed, snorkel, and sift to produce sound to communicate. The trunk can hold over five liters of water and this can be sprayed over their body to help with bathing and cooling. Elephants have six sets of teeth, all of which are present in the skull at birth. Tusks are modified upper incisors that are made of ivory. Not all elephants develop visible tusks and only some elephant males have obvious tusks. Most females and some male elephants have small tusks, called tushes. Tushes have a slightly different composition to tusks and can break quite easily.

Elephants have mighty hunger and can be described as either eating machines or manure factory. They do not grind their food as cows, goats, deer and often feed for up to 16 hours a day. In the wild, one animal generally consumes 180 kg of vegetation and drink 150 liters of water per day. They mostly feed on grasses however they also eat a large amount of tree bark, leaves, roots, vines, and fruit. Due to lack of grinding, elephant’s digestive system works less than 50% efficiency. Elephant’s massive hunger and inefficient digestive system leads to lots of manure production. An elephant defecates for 12 to 15 times a day, and they expel 60- 80 kg from digestive system. Elephants play a vital role in the ecosystem as they disperse many seeds along with defecates as they travel.

Elephants also generate lot of biogas as methane in their digestion process and daily methane generation of an elephant is able to operate a properly equipped, car for 30 km. Elephants spend approximately three-quarters of each day for traveling to find food and water and they eat even on the walk. Elephants usually rest during the hottest part of the day and feed more in the morning, late afternoon, and evening. The strong, vertical legs of elephants allow them to stand for long periods of time without using much energy. Elephants can sleep whilst standing. Elephants walk on their toes and have a thick, fibrous pad on each foot that cushions each step.

Elephants are very active animals and friendly. They had been tamed and lived with people as their best companion for many centuries. Despite their heavy weight and size, elephants are speedy runners who can reach speed up to 25kmh in very short time. Elephants have peripheral vision, which enable them to see both front and rear without turning the head. However elephants are born blind and their vision improve as they mature. Elephant are color blind and they can see green and red during day time and can see blue and violet light at low light conditions. The sense of smell and hearing ability of the elephant is far greater than other animals. Elephants have great memory power like a human's brain in both structure and complexity. Researchers have found that elephants exhibit many behaviors that reveal substantial intelligence, including grief, altruism, mimicry, play, art, use of tools, and self-awareness. Best example of elephants intelligence is that the ability to recognize their reflection in a mirror. Elephants can store large amount of data in their memory with lot of details from birth to the death. Due to same facts, he oldest female give direction to heard to avoid danger zone and threats in consultation of her life long memory.

Elephant can sense the relative humidity variation in the air and it can detect a water source that is as far as 20 km away the animal. Elephant hearing range is identified as 14-12,000 Hz. Elephants communicate over long distances using low-pitched sounds that can be heard over 3km away. This communication is important for elephant survival. Females in estrous make specific vocalizations that bulls can follow, and warnings can also be given about predators that are a risk to young calves. When a predator is in sight, adult elephants will emit loud warning calls that prompt the herd to huddle closely together with the youngsters in the middle for protection. Elephant use scent as an important communication method and they have highly developed sense of smell. The trunk is especially important for this form of communication. Elephants will touch each other regularly to communicate different messages and feelings including excitement, dominance, and their reproductive status.

2.2 Thermal Distribution and Cooling System of Elephants

Elephants generate large amount of heat due to internal metabolism activities and physical movements. The heat signature photograph taken on an elephant is illustrated below. Red color indicates the hottest areas of the skin and yellow represent the moderate temperature and blue represent the cooler areas of the skin.

Generally, the size of the ears of an elephant is directly related to the amount of heat dissipated through them and ears act as the radiator fans at times. The difference in ear size between African and Asian elephants is based on their geographic range. Ears help to regulate body temperature and flapping the ears helps to cool an elephant in two ways. Ears of an elephant act as a fan to move air over the rest of the elephant’s body, also the blood acts as a coolant where internal heat is dissipated to atmosphere and cools down in the ears.

As the cooler blood re-circulates through the elephant’s body, the animal’s core temperature will decrease several degrees. The hotter it is the faster the elephants will flap its ears. On a windy day, however, an elephant may find it easier to simply stand facing into the wind and hold its ears outward to take advantage of the breeze. An elephant may also spray water on its ears, which also will cool down the blood before it returns to the rest of the body. Large ears also trap more sound waves from surroundings.

Elephants have grey-blackish skin. It varies from paper-thin in some places such as the inside of the ears to as thick as over 2cm on other parts of the body including their backs. Young elephants have reddish brown hair covering their bodies that diminishes with age. Elephant skin lacks moisture, especially around the joints, to provide the necessary flexibility for the motion. The wrinkles in an elephant’s skin help to retain moisture, keeping the skin in good condition. Despite it’s rough and dry appearance, the skin is delicate and soft. Elephant’s take frequent mud baths or dust with soil to protect against insects, to control body temperature, to condition and moisturize the skin, and to protect against sunburn.

Elephants have very few sweat glands. The few sweat glands that an elephant has are located on the foot, near the cuticles. This results in a skin that is dry to the touch but soft and supple and wet area around the top of their toenails.

2.3 Elephants Instinct and Weaknesses

Elephants are the majestic animal in the jungle and any jungle that provide home to elephants are rated as top attraction in the world. Elephants are harmless animal if not provoke or if one does not try to approach their territory without permission. Scientist found that elephants have routines like annual migration from place to place to survive the harsh environment and they look after each other in the heard collectively. Elephant herds are looking after by a leader who is accepted by all. They have their own unwritten laws and regulations. The who challenge the rule of law in the community are thrown away from herd and those outlaws are thrown away from the heard and some elephants live lonely.

Many researches had been conducted to identify the elephant behaviors and it was identified through research that elephant’s intellectual capacity is unmatched with any other animal species. Elephants are fast learners with very good memory. In recent research it was further found that elephants communicate through low frequency range even when they are apart by few kilometers. Also it was identified that their feet are highly sensitive to vibration and they can filter vibration that transmit through soil and identify the seismic readings effectively to monitor the movement of other elephants in the herd even they were as far away by miles. The sense of smell and highly sensitive hearing of the elephants are very developed compared to the human and elephants use these senses very effectively in identifying the dangers and to find their survival in the jungle. Elephants do not tolerate high noise, as their ears are highly sensitive. Elephants further found to be very responsive to of heavy smells and avoid those heavy smells.

Even though elephants are bulky in size they are fast runners and they can achieve top speed of 60 km per hours under a minute and chase down a human and toss him up and down few times and stamp till death. Humans from ancient times knew that the elephants never play with fire and they well know the danger that poses by fire as individual and to the total population of the herd. Hence it has great respect for fire. Elephants respect other animals in the jungle and only bring retaliatory action when they were attacked as individual or as heard. Elephant’s memory and intellect were identified from ancient times and they were captured and trained to do heavy works that need more muscle power than humans.

3.0 Insight into Human Elephant Conflict

Ancestors believe that best act to demonstrate ones braveness is through the killing of majestic animals and showcase the tusks at their homes. Hundreds of thousands of animals around the world had been killed for pleasure. Human conflict with elephants spared into centuries. So far people who had upper edge with analytical brainpower and used many weapon to kill elephants to extract of their tusks.

With the growth of population and under the flag of development, people encroached the jungle to built the farmland, cities, highways, airports, road networks and many modern human needs. Elephant being the largest mammal on the ground didn’t respect human rules on their habitats and challenged the human existence in their habitats by encroaching in to the human occupied territories. Human more often took offensive approach in these elephant’s conflict and sometime acted with heavy cruelty without being punished for their crimes. Today even there are laws to punish the killing of elephants, the existences of elephants are threatened and they had become one of fast diminishing animal population in the world. So governments around the world had impose law banning the killing of elephants and start punish people who broke the law.

Even though the written law is applicable for humans, the governments were not being able to bring the elephant under the law. Hence governments seek the assistance of scientist in identifying the elephants and find methods to keep them away from humans. Till today hundreds of researches conducted to identify the elephants and exploit their weakness in driving them away from human define boundaries. But all efforts were ineffective and elephants had been able to find ways-and-means to avoid those traps through their fast leaning skills and high adoptability. Elephants had been able give a meaning to their names and today policy makers are helpless against the might and intelligence against the elephant.

3.1 Co-existence of Humans and Elephants

The environmentalists who had been living in city with all the comfort and not lived in bordering village for month facing the elephant conflict day in and day out are trying to come to conclusion based on emotional sense. However history repeat that these methods are not practical for establishing solution for the problem. Rural community who had lived with elephant encroachments even in their lifetime never expects the elephant to be killed. They still love this majestic giant. However they are asking a solution for coexistence. Hence it is important to introduce a tool that will keep elephant within their allowed adequate territory.

The coexistence will benefit both the human and elephant where loss of lives in both sides will be minimal and both parties will enjoy their share of life. Coexistent solution will provide the assurance that farmers will have access to their share in agriculture. 3.2 Need for Exploitation of Elephants Senses in Boundary Fence

For decades human has been engineering tools and systems to keep elephants away from the rural farming community but failed. The failure of these system were mainly due to none proportional response of these devices as elephants get closer and closer. Elephants were faced with equal size response at each time and they got easily adapted to the threatening force. Hence, humans no longer will be success in coexistence without a barrier fence that can give proportional response to elephants as they get closer and closer. In simple terms, separation fence should be smart enough to adopt and intensify its impact, as elephant get closer to the separation line. If not, elephants will easily use its muscles and adaptations ability to overrun any defenses that human put in their path hindering the access to the separation fence. Further the instrument that needs to be installed in the fence should be able to give a physiological punch without physically harming the animals.

4.0 Proportional Response

Fire, sound and even aground slope are the three main tools that are being tried to use against the charging elephants. However the impedance of these tools against the distance between the source of emission/obstacle and the animal need to be increase, as they get closer. This is called a proportional response. However use of sound in proportional response can be equally disturbed the humans and all the animals in the surrounding areas. So use of sound in proportional response to be reconsider. But the proportional response in ground slope preparation and thermal punch can be easily adopted for feasible solution. Thermal response is considered in below considering the ground slope response is simpler in design and can be used as an integral part of the construction work thermal response.

4.1 Heat Spectrum

Thermal energy released from heat source is travel in three modes. Conduction and convection need media for the heat transmission. However radiation does not need medium for heat transfer and can be felt far from the heat source due to its transmission through electromagnetic wave nature. Use of infrared bandwidth of the light spectrum for heat transfer is becoming popular today. It is used in paint booths, worming for animals during cold weather, and medical treatments are very popular today.

4.1.1 Short-wave Infrared Heater Lamps (0-1000nm)

Lamps that emit short-wave infrared waves reach maximum temperature almost immediately and is the hottest option. These lamps run up to 300 °C and have a radiating efficiency of 80%. Hence, short-wave lamps provide an instant and intense heat source. The lamp has the capacity to provide rapid thermal punch and in the process waste very little energy.

Figure 4., illustrate that short wavelength infrared light has highest skin penetration compared to the other wavelengths.

4.1.2 Medium-wave Infrared Heater Lamps (1000-3000 nm)

Medium wavelength lamps start up time is relatively slow (usually under 30 seconds), also with a lower heat output of 900°C and reduced efficiency. Overall efficiency of the lamp is reduced to 60% and 40% heat generated through lamp is lost in heating the air as opposed to directly targeting animals. So as wavelength increase its bandwidth lamp will struggle to get the same kind of warmth from lamps as it is mounted inside.

4.1.3 Long-wave Infrared Heater Lamps (3000-6000 nm)

Finally long-wave infrared heat runs much cooler at 300°C, takes around 5 minutes to warm up, and only 40% of the energy here is converted into heat. This means that around 60% is wasted heating the air. This type of lamp does have its uses in environments where no glass is allowed or indoor spaces where heating air wouldn't be a big waste of energy. However the long wave infrared lamps heat specific area with zero light levels.

Heat punch is a sudden rise of temperature in your skin that feels same as you had unexpected punch. Though it is illegal, heat punch is briefly used against the slow drivers in highway by prime mover drivers in Australia to repel them from fast lanes in highway. Generally a properly designed infrared inferred lamp fitting could heat up an area of 25m2 very quickly due to its effectiveness in shortwave length. Since electromagnetic waves do not worm the medium it travels and increase of temperature start as it touch the surface. This characteristic is highly suitable to drive away of elephants from the fence as there is promotional increase of heat as elephants as they get closer and closer to the fence. Correct use of low wavelength in infrared light is important in this application as we need good amount of penetration into the skin, as we need to penetrate the thick skin of the elephant.

4.3 Selection of Infrared Lamps

Short wave infrared lamp is most suitable in penetration of heat through the skin and giving proportional response in terms of distance. Every animal that roams in the jungle during daytime is exposed to inferred lights that is emitting from sun. Hence use of inferred light on animal does not pose any additional health impact to the elephants or other animal. Hence the short wave infrared lamp is identified as most suitable lamp for the application.

5.0 Proposed Elephant Fence with Heat Punch

Generally every smart fence need mode of detection of when and where to deliver its intended function. Hence Elephant fence proposed for this application is expected added with a motion sensor to generate trigger response for inferred light to turn on. This feature will save lot of energy usage from the power supply and delivery effective proportional heat response to approaching elephants in needy areas only. The most common motion sensors available in the market are capable of tracking movements is approximately 10m in distance from the mounting position and it will act as a switch that open and close the power supply into the inferred lamp. The trigger response can be adjusted for heat impact up to 15 min where the adjustment can be made as necessary.

Elephant fence that is proposed with motion detection technology and inferred heating element can be illustrated as below.

6.0 Discussion

Human-Elephant conflict in Sri Lanka is one of key issues that need an immediate solution. Government, and non-government organization had used many tools and techniques to keep elephants away from the agriculture lands and help farming community. However elephants found to be returning to the same place by overcoming the traps and fences. Elephants found to be an intelligent enough to create headache for the most intelligent species in earth. Adoptability and unexplored communication channels of elephants have been the main tools they used to overcome all the challenges that had been created by humans in restricting their movement on ground. The predictability and non-proportional response of old techniques are found to be main draw back that could help elephants to get adopted to the traps very quickly.

Hence if new technique is proposed, the new techniques needs to be fabricated as a permanent solution for this problem having considered all the failures of previous tools and techniques including the electric fence. The use of uphill slope that increase as it gets closer to fence with thermal punch can be the most ideal as it could give two-dimensional impacts to elephants that may be hard for them to configure at their intellectual levels.

The color blindness of the elephant in day and night can also be easily used to camouflage some area of the villages from elephants. Illumination with blinded colors can be added as the third-dimension to proposed protective fence to further strength its ability to resist elephant. The techniques discussed in this article are based on scientific principals and hence it is proposed that need for modelling these features in a sample fence before the full scale implementations.

7.0    References

1. C. T. Herbst, A. S. Stoeger, R. Frey, J. Lohscheller, I. R. Titze, M. Gumpenberger, W. T. Fitch. How Low Can You Go? Physical Production Mechanism of Elephant Infrasonic Vocalizations. Science, 2012; 337 (6094): 595 OI: 10.1126/science.1219712
2. Sunday Times: Ditch Electrical Fences Human- Elephant Deaths are rising
3. https://elephantconservation.org/elephants/just-for-kids/#:~:text=http%3A//www.telegraph.co.uk/earth/wildlife/7663160/Elephants%2Duse%2Dhot%2Dspots%2Dto%2Dstay%2Dcool.html
4. Human- Elephant Conflict Prevention toolkit and Best Practices – East Africa, May 2016
5. Human-Elephant Conflict in Sri Lanka- Pattern and Extent- T.G. Supun Lahiru Prakash, A.W. Wijerathne and Prithiviraj Fernando

Eng. Ruwan Nagahawatte

Eng. Ruwan Nagahawatte has more than 15 years of experience in designing, construction and operation of power generation system in Sri Lanka. He is graduated from University of Moratuwa and involve in sustainable engineering practices.