Human crocodile conflict

Need for a Conservation Action Plan:

By Dhaneshi YATAWARA

According to legend the yearling of the female crocodile which lived in the Matara river (Matara Kimbuli) was not a man eater. Yet interpreting this peculiar female crocodile character is still debatable among the literate. There are numerous explanations for this 'Matara kimbulige petiya'. This story is not a literature survey on the poem. This is an expedition on the current situation the crocodiles of Matara are facing.

The commonest crocodile in the country is the mugger crocodile known as 'hela kimbula' in Sinhala. According to Sri Lankan herpetologists the mugger it has only a few favoured natural habitats left where most of these habitats are cleared, altered and under pressure by human activities. The salt water crocodile or the saltie is a common sight along the Nilwala river in Matara. Today these salties struggle for their survival giving rise to human - crocodile conflict. The IUCN 2007 Red list recorded the salt water crocodile under the 'nearly threatened' category.

A modern crocodile exclusion enclosure in the Nilwala river

Mugger burrows - some are about 20m deep

Anslem de Silva

Human-crocodile conflict mitigation involves both awareness and the building of some expertise in controlling 'nuisance' crocodiles as well as strategy for translocation when found necessary," said Vice Chairman Crocodile Specialist Group of the IUCN/Species Survival Commission for South Asia and Iran Anslem de Silva. "However, we should be extremely careful of such translocation as the 'homing' instinct of this species is now well established," de Silva explained based on his research in the Nilwala river carried out to investigate the reasons for Human/Crocodile conflicts. The three day research funded by the Mohamed Binzyed Conservation Fund, basically focused on proposing methods on how to minimise this conflict among the vulnerable communities inhabiting the Nilwala river from Modara (the Lands-End) up to Paraduwa in Matara district.

On their three day mission the researchers collected data on eight human deaths due to crocodile attacks and ten cases of attacks resulting in minor injuries. "However, it is felt that most of these accidents might have been prevented if the victims knew some of the basic safety measures," Anslem explained.

Highly threatened

The alarming revelation in the survey was that 95% of respondents considered that crocodiles were not useful or rather did know the ecological roles played by the crocodiles.

Many have said crocodile flesh has curative properties for asthma and improves eyesight.

Although the crocodile is a protected animal, under the Flora and Fauna Act it is illegally hunted mainly for its flesh. Destruction of crocodile eggs and clearing its natural habitats still continue. In addition, occasionally a man-eater gets killed. "Shooting or capturing any specific man-eater is still questionable as an Australian study in 2005 (Caldidicott et al.) indicated that there is no guarantee that the crocodile responsible for the attack could be captured," Anslem de Silva further explained.

Killing of yearlings and sub-adults which get trapped in fishing nets is another threat crocodiles face in Matara. Some drown in the fishing nets and die. "In fact, one fisherman informed me that he killed five young crocodiles that had got trapped in his fishing nets in the past," de Silva said. Occasional attacks on humans give crocodiles a bad reputation. Just a single confirmed man-eater inevitably leads to many of the crocodiles in the vicinity being killed.

Forty-seven percent of the people interviewed have said that they have heard that when a crocodile holds on to its victim, the stomach or the belly of the crocodile should be stroked or tickled, then it will release its bite, whilst 53% did not know any methods to escape from a crocodile's grip. "when I was a young boy my family was living in the ancestral house in Fort, Matara near the Nilwala River during the 1950's. Those days I kept a yearling saltwater crocodile for about four years which I collected from Nilwala River. During this period, in order to verify this popular belief, I use to stroke the belly of the captive crocodile, which responded immediately by becoming passive and did not struggle.

When repeated it produced the same results," de Silva said. Using another yearling crocodile during the present study, de Silva experimented the same method and the animal has shown the same behaviour.

Dumping garbage on the river bank attracts crocodiles as well as its predators like the water monitor. It was observed that large water monitors ('Varanus salvator') swallowing crocodile yearlings as well as large crocodiles swallowing adult water monitors.

"During the survey, we found out that several slaughterhouses and fish stalls discard their refuse into the river, and in two such places crocodiles are attracted when fish and beef by-products are thrown into the river," de Silva said.

The water monitor attacks and feeds on large number of animals, including other reptiles, such as venomous and non-venomous snakes and crocodile yearlings and crocodile eggs. In addition, eagles, hawks and mongoose have all been observed to prey on yearlings.

Human errors

"Regarding the human-crocodile conflict and attacks, investigations revealed that in almost all the case studies the fault was on the part of human beings.

Many use insecure crocodile pens for bathing and washing," de Silva added.

Regarding the approximate length of the crocodiles seen by the interviewed families, 76% stated that they have seen crocodiles possibly measuring over 3 meters in length. Nearly 46 % of respondents have observed crocodiles between 10a.m. to 1 p.m.

An intensive awareness program coupled with protective measures like installing crocodile-pens, crocodile-fences and installing warning sign boards in risk areas should be carried out, he suggests.

As far as crocodile attacks on pet and farm animals is concerned, most of these attacks have taken place in the river-land interface, pointing to the negligence of the respective owners of these animals.

"During our survey of residents living near the river we observed that some tie their dogs in the backyard of their homes adjoining the river, which prompts the dog to bark at the slightest disturbance which unfortunately attract crocodiles to attack these pets," he explained.

Most of the riverine mangroves have been depleted mainly due to human activities.

As de Silva further explained the people living along the river should be informed of the legal aspects of the river reservation area, such as the 20 metre river bank reservation that belongs to the government, thus any destruction of the mangroves may be liable for legal action.

Install proper crocodile pens in places where it is need by the community. Installing a crocodile fence where crocodiles frequent into compounds during the night.

Crocodile fences

To enhance aesthetic and traditional beauty I recommend building a durable pen using Kitul planks on 3 sides which will create a 10 x 5 metres square, de Silva explained.

Mugger crocodile (hela kimbula) in Yala

But it should be strongly secured from the front with strong wire mesh with a door.

The kitul planks should be around 15 centimetres wide and when installed in water they should be approximately 1.5 metres above the river water level during high tide. The space between two planks should be 10 centimetres. There should be a rough concrete platform and steps leading up to the water.

Considering the fences it should be erected on a secure foundation and should be constructed so that half the land area is for the occupants and the other half for the river or rather for the crocodiles to prowl at night.

"Thus, we create land area for the crocodile, as well as protect the people and their pet animals. This technique has never been attempted anywhere in the world.

In addition, a door should be fixed to this fence so that people could use both land spaces during the day," de Silva explained.

Crocodiles are a keystone species that maintain ecosystem structure and function through selective predation on fish species, recycling of nutrients and maintenance of wetlands in drought. Thus, it is important that we conserve these reptiles and their natural habitats.It is felt that a Conservation Action Plan should be initiated in the country which addresses the specific issues of the country, according to de Silva. Fortunately, major natural habitats of the mugger are in some of the wildlife reserves, such as Yala and Wilpattu National Parks.