Dr Shahed Hassan
For long we have merely observed many a butterflies flying away from beautiful gardens laden with colourful scented flowers before the start of a strong wind or a heavy rain. In many cases crawling lizards and similar species have been seen to start strange behaviour couple of hours before a seismic vibration. We have perceived these symptoms as the coming of an earthquake. Such behaviour of animals prior to occurrences of minor or major geophysical aberrations remains a subject of curiosity and scientific inquiry. Unfortunately, no major breakthrough has been made in this field as of yet.
Countries experiencing frequent natural disturbances and calamities have developed and are equipped with scientific devices for advance forecasting of approaching disasters but still more effective instruments are needed to avoid life and property losses. It is assumed that Mother Nature probably has given all the required apparatus since time immemorial, within the hidden sensory organs of both human and nonhuman primates as well as other species of life. The recent discovery of magnetosensitive global positioning system or GPS cells in the pigeon brain that allows the species to register its own navigation map is a commendable scientific achievement. Further research works are still ongoing as to reveal presence of iron particles in birds, ducks and fish to store spatial memory and weather reading skills.
Nevertheless, observation on unusual behaviour of different species of birds and other animals never escape the notice of the people who, for their living and survival, largely depend on nature. They take into account all the biotic creatures available in the four major spheres of nature which include the biosphere, atmosphere, lithosphere and the hydrosphere and do not remain blindfolded when any strange movements among them are noticed. For each deviation from usual pattern of behaviour the local people derive certain interpretations and take necessary actions for themselves. In fact, the animals (including birds and aquatic species) are environmental channels to tune weather forecasting and geophysical disturbances and this branch of knowledge is reflected in mythology and other forms of oral traditions.
The keen observers have found that prior to earthquake some animals eat more, birds change their songs or tunes, underground animals come to the surface, caged animals become highly agitated, aggressive and fearful or try to escape. Among the domesticated animals, cats cry or act nervous, dogs notoriously howl and sniff the ground, insects suddenly disappear and appear in swamps, and aquatic animals leave the water or head far out to sea. People living in close contact with nature believe that there are many more biotic indicators to predict the change in the environment. Unfortunately, there is a serious dearth of research and scientific explanations for such nexus.
It was reported that dogs ran away to hill tops in north of Phuket (Thailand) long before the people, mostly tourists, in the area realised the coming of the Tsunami (Dec 26, 2004), so did the elephants in Anadaman Islands and Sri Lanka. It is indeed incredible how the animals sense these incidents before humans. When the tsunami struck, there were much human causality but hardly a few animals died. The fishing communities living in Japan's Wakayama coast seriously try to locate the height of Tsubame birds' nests during early summer only to guess the height of sea waves to come along with late summer typhoons. Usually sea waves never reach the nests. Wakayama people consider this indicator as more effective than what the Japan Meteorological Agency transmits through weather bulletins.
As regard the migratory marine mammals, scientists explain that usually their internal cerebral magnetic compasses guide their travel routes and distances. But any derangement or disturbance in the magnetic fields influence their compass thus resulting into their disoriented course and direction. Small creatures like ants scurrying about with their eggs, birds having a dust bath and spiders making webs in the shade, all signify the onset of rains. Birds flying low usually signal the coming of a storm is known to those who live along the coastal zones. It is, therefore, by reading behavioural signs and monitoring their actions humans can get a clear idea of what the weather has in store for them. It is known from the traditional apiarists or the bee keepers that when the bees store excessive food in their hives and seal with wax, heavy and substantial rains are expected. Decline in the number of barn owls indicates approaching of extreme weather. Examples cited so far are mostly derived from published, unpublished reports and personal research works abroad.
In Bangladesh, such unexplained barometric indicators are not less in number. From a recent investigation in the northern part of the country, affected by both hot and cold waves, it has been observed that the rural people keenly observe and largely depend on the behavioural changes among the pet animals, wildlife, fish stock and flying insects and birds.
On the basis of observation their livelihood plan is designed and crop calendar is prepared accordingly. When ants are seen to carry their eggs and head northwards, it is said to be an indication of positive sign of rain and if the trail follows southwards, it is an indication of drought soon to come. An abundance of dragonfly signals heavy rains. The local seagulls tend to change the usual style of laying eggs right before a hail storm is due. If the same species flies to certain height and then dives down below and repeats this action exactly three times in a particular place before settling down indicates imminent rain within a week.
Rain forecasting can be detected from the way hens, ducks and pigeons spread and dry their wings. Forecasting of flood is perceived from appearance of red stripes on body of small fishes and frequent urination by cows at waning moon night. Fireflies flying off in swarms are considered as an indication of bumper growth of vegetables. Similarly, bats building nests in barns are considered as a sign of good crop harvest.
Bangladesh is blessed with at least five agro ecosystems within the boundary of 55,000 sq miles and each ecosystem has its unique but threatened biodiversity. Thus, people living in those ecosystems obviously depend on multiple nature-gifted indicators to predict weather, both favourable and adverse. Here is one observation from the coastal zone where the Rakhains (an ethnic minority) live. The entire agricultural pursuit of the Rakhains depends on appearance of rings on feet of a particular species of frog. More the number of ring appearances, more the rainfall apprehended and accordingly the type of crop to be planted is decided along with a product marketing strategy. In fact, such information is only orally transmitted from one generation to the next. Documentation, along with scientific explanation, would obviously help develop a scientific Farmers' Almanac for the country. To this end, collection of field data is not a difficult task. The problem remains on scientific explanation. We often casually say that animals have ESP or a sixth sense. In reality, the animals are not much different from human beings except that their existing five senses are greatly used. In-built barometric devices and hydrostatic pressure are not only felt by animals and fishes but also by people living at certain altitude and close to water bodies.
Attempts have been made in this article to highlight behavioural changes in animals, birds and fishes only to draw attention to our local scientists to the fact that animals can detect low frequency or infrasound sound which we, human beings, would not recognise as sound at all. Animals' sensory physiology is super-sensitive to temperature, touch vibration, electrostatic and magnetic fields which gives them a head start in the days and hours before surrounding weather changes or approaching calamities. A simple man-animal analogy has been drawn here but it still remains unanswered what physiological factors operate in animals. Presence of all the technical devices needed for weather reading in animals makes them 'living barometers', about whom we do not know much.
Shahed Hassan is Professor of Anthroplogy, University of Dhaka.