Nature’s Weather Forecasters

Do animals have built-in weather detectors? 
Nature’s Weather Forecasters

23rd of March was  World Meteorological Day. Before the discovery of sophisticated weather forecast equipment and satellites, it was simply animal and plant behaviour that had warned our ancestors of weather changes. Animal behaviour can still be used to predict weather, and ZooLander looks at some of the animals that have the ability to predict weather patterns.
Today meteorologists use satellites and there are state-of-the-art weather stations around the world to monitor the weather, and for forecasting. However, even with  the modern technology of  today, there are so many variables, that 100% accuracy in weather forecasting is difficult. But our ancestors with traditional knowledge could predict the weather by animal and plant behaviour, with acumen gained from generations before. Some farmers even looked at these nature’s signs to decide on when to cultivate and surprisingly these signs often were accurate.
Birds, bees, colours in the sky, formation of clouds and the colour of falling rain, are some of nature’s signs for predicting weather.
The swallows are perhaps the most common weather forecasters known to  many Sri Lankans. Their Sinahala name wehi lihiniya translates into English as ‘rain bird’. It is believed that if they fly low, then rain will follow by evening. This prediction is often more accurate than weather forecasts that are relayed over TV  or Radio. But how do swallows know that it would rain? Or is this   just another myth?

Wehi lihiniya - or rain birds
Zoologists who studied the movements of swallows found that there is actually a scientific basis to their behaviour. Swallows that often fly high, come down mainly because the insects which they feed on, descend to lower levels on rainy days. Scientists explain that this could happen due to changes in  ‘air pressure’ shortly  before rain. The impact of air pressure could control the movements of the little insects, more than that of birds, resulting in the swallows having to come down to feast, just before it rains. It is in fact the insects that sense the change, but it is the wehi lihiniya that gets the credit in issuing the warning about the oncoming weather changes -- in the manner of a skilful meteorologist.
Scientists have conducted research on several species of birds, and confirm that they are able to foretell the weather, although it is yet to be established, to exactly what degree. In other countries this phenomena has also been tested with some other birds like the black cockatoos. It is said that these birds will fly down from hills and mountains and will glide towards coastal areas, particularly in the early mornings when heavy rain and storms are imminent. A further explanation for this behaviour could also be the changes in plant behaviour such as  opening of  seed pods in certain trees, due to the changes in air pressure.

Birds’ nests too could give clues
In some villages in India, the village folk look at a particular bird species to have an inkling  about the upcoming rainy season. This bird builds nests on trees and if the nests are toward the top of the trees, then heavy rains follow. But if they are lower down, there will be less rain think these villagers with centuries of experience. An Indian researcher having studied this phenomenon also found that the basis could be interpreted as, when the nest is near the centre of the tree, close to the trunk, it means heavy rains. But if birds build their nests on the tips of the branches, it means scanty rains and a drier season and the birds do not have to worry too much about getting their nests destroyed by heavy rains and winds.

Fish
Both saltwater and freshwater fish have been known to change their behaviour prior to weather changes.  An explanation put forward is that shallow dwelling species such as the plankton can sense atmospheric pressure and temperature changes, and change their behaviour.  This may then trigger a reaction along the food chain.
Many species of fish will ‘bite’ prior to an intense change in the weather.  Quite often fish will swim nearer to the surface and will take bait quickly before the rains come. Several species of freshwater fish that frequent the upper reaches of rivers, streams and creeks are often caught near the mouths of rivers and creeks before flooding rain spells.
Researchers observed this type of behaviour among a group of sharks as they tracked the sharks’ movements during tropical storm Gabrielle and hurricane Charlie. When the barometric pressure dropped just a few millibars - an occurrence that causes a similar change in hydrostatic pressure - several sharks swam to deeper waters, where there was more protection from the storm.

Ants
Ants are the most reliable weather forecasters on earth, say researchers.  A change in the weather is inevitable if the ants behave in a manner which is out of the ordinary.  They will be extra industrious and work frantically to clean out nests, construct and move into new nests, and gather food, when heavy rains are on the way.
Ants building cones or crowns around their nests on the ground, is an excellent indication that rain is on the way.  When ants build nests on top of fence posts or old stumps, rain is imminent, as per  folklore. Nests can also be found in or around any object that the ant deems to be higher than ground level --  when rain is on the way.

Do animals have a sixth sense?
Yala National Park was severely damaged by the 2004 Tsunami. Lots of visitors to the park were killed, but very few  large animals had died. It is said that the animals almost ‘flew’ away from the marauding sea. It is said that elephants in Thailand had moved inland to higher ground, just a few minutes before the Tsunami. Scientists say the elephants could sense the vibrations in their feet. It could be the same in the case of  earthquakes when animals seem forewarned.
It is believed that birds and bees too can sense earthquakes. A few minutes prior to the earthquake, everything becomes completely still - no movement or sound.  Birds stop singing and chirping and flying around.  Insects cease making noises and moving about, and there is a total silence and stillness.  Seconds before the earthquake dogs will start howling and other animals become agitated.  After the earthquake has passed, the silence is felt again for a couple of minutes.
It is said that animals could be having a sixth sense helping them to make weather predictions. But scientist believe they just have the five senses which we all possess; however they are successful predictors that have more powerful senses helping them make accurate predictions...

Published on LakbimaNews on 01.04.2012 

Celebrating Aquatic Animals, Commemorating World Water Day

Aquatic Life in a Water World

March 22 is World Water Day. Water is essential for all of us and we cannot live without drinking water. In fact it is believed the life of the Earth began in water, so Earth is indeed a water planet. ZooLander looks at the amazing diversity in aquatic animals.

We can live for a few days without food, but can we even think of surviving without water. But there are some animals that need water based mediums to live in, as if their very survival is dependent on water. These are aquatic animals and live in water for most or all of their life. We breathe through our lungs, but most of these aquatic animals, like fish, use their gills, a special organ that can extract the oxygen from water. However there are other aquatic animals such as whales and dolphins that breathe air directly from the atmosphere.
The environments these aquatic animals live in are of two types - freshwater or saltwater. Creatures that live in saltwater mediums like the oceans are known as marine species. Zoos and aquariums are the best places for observing these animals and the best place in Sri Lanka to study marine species in captivity, is at the aquarium in the Dehiwala zoo. Diving or snorkeling is the other option, if you want to see them in their natural habitat.  As many of us cannot swim or dive in to the vast oceans and as it is also a specialized technique that needs to be learnt and practiced, the majority has to go to aquariums to study these beautiful animals.
The zoo aquarium is full of freshwater fish. There are lots of endemic fish species that are native to Sri Lanka, which cannot be found anywhere else in the world. This section in the aquarium is the most important and interesting corner to watch. There are other interesting river fish from other parts of the world too that you can observe at the aquarium. Zoolander has previously reported on the aquarium’s freshwater inhabitants - the giant Amazonian fish Arapima, notorious Piranha and the endemic Sri Lankan fish Pathirana Salaya. There are other  interesting fresh water fish swimming in lit-up tanks, placed in darkened passages.
The aquarium is also home to many varieties of marine fish. Those who are associated with corals are the most beautiful of them. Can you recall the Moray eel that Zoolander reported on sometime back? It’s an interesting creature found in coral habitats. On a visit to the Dehiwala zoo, one can observe many such aquatic creatures in the aquarium.
Whales and Dolphins are the most popular aquatic mammals, but none of them can be seen in captivity in Sri Lanka. However, the Dehiwala zoo is not without a representative of the aquatic mammal family. The performing sea lion is the only aquatic mammal at the Dehiwala zoo and with the daily performances, it is one of the most popular characters, entertaining visitors.
Amphibians are another aquatic form of animals that can live both on water and land and the aquarium still has its corner for frogs.

Fish gills
Have you gone to the fish market to buy fish? Or have you seen the fish on the kitchen table ready for cooking? If not, have a look at the head of a small or medium sized fish and you will notice the gills, which are used for breathing by taking oxygen from water. But how do these gills function? Have you ever given a thought to it?
The gills allow fish to absorb oxygen from the water and in the fish they do the work, of lungs. In lungs, blood in tubes flow near the surface of tiny air sacks, oxygen transfuses from the air in the sacks into the blood, and carbon dioxide transfuses from the blood to the air in the sacks. A fish’s gills work exactly the same way, except that it is water in the gill structures that handle the transfusion, and are visible dangling in the open water instead of being hidden inside the lungs.
Gills themselves have a car radiator-like appearance. Most fish have 4 gills on each side, consisting of a main bar-like structure that has numerous branches as those found on a tree, and the branches consisting of even smaller branch-like structures. This arrangement of cells allows for a very large surface area when the gills are immersed in water.
Functionally, the mechanism for pumping water over the radiator-like gills seems to vary depending on the species of fish. In general, a fish is able to reduce the pressure in its mouth cavity by lowering the floor of the mouth and widening the outer skin flap that protects the gills, called the operculum. This increase in volume lowers the pressure within the mouth causing the water to rush in. As the fish raises the floor of their mouth, an inward fold of skin forms a valve of sorts which doesn’t allow water to rush out. The pressure is then increased compared to the outside of the mouth and the water is forced through the operculum opening and across the gills.
This wonderful organ, the gill, has allowed fish for millions of years to enjoy the wonder that is underwater basket weaving. The next time you see a fish swimming around you can smile to yourself knowing that they are working much harder than us to breathe.

Fish that can live outside water
If you happen to watch the popular Sinhala TV programme Atapattama, you may have seen a large Gourami fish that comes out of the water and even allows children to cuddle it for about 15 minutes outside water. It became fascinating news and got much publicity. But fish experts say this is not a new phenomena and fish like the Gourami have the ability to live outside water for a longer time as they have another special organ in addition to gills that allows them to absorb atmospheric oxygen. This organ is called a labyrinth organ which acts as a lung helping the fish to breathe in air, allowing labyrinth fish to take in oxygen directly from air, instead of taking it from the water in which they reside with the use of gills. The labyrinth organ helps the inhaled oxygen to be absorbed into the bloodstream. As a result, labyrinth fish can survive for short period of time out of water, as they can inhale the air around them, provided they stay moist.
Labyrinth fish are not born with functional labyrinth organs. The development of the organ is gradual and most labyrinth fish breathe entirely with their gills and develop the labyrinth organs when they grow older as per the experts who studied this fish variety. It is not unique to  Gouramis -- if you remember ZooLander wrote about this special organ, when reporting about the zoo aquarium’s Dino Fish - Arapaima. The Arapaima lives in the Amazon and they too have the labyrinth organ.
Aquatic creatures are very interesting animals, even though we are not as familiar with them as with land animals. The zoo’s aquarium will provide a good opportunity for you to observe these fish. How they breathe underwater, how they swim, how they interact. Why not make a visit to the zoo once again and carefully observe these aquatic marvels and be delighted by them

Interesting facts about fish and other aquatic creatures

1. Sea turtles absorb a lot of salt from the sea water in which they live. They excrete the excess salt from their eyes, which makes them look as though they’re crying.
2. Prehistoric turtles may have weighed as much as 5,000 pounds.
3. As it gets older the cockle just adds another layer to its outer shell. To work out their age you can count the rings on them just like on a tree.
4. A goldfish has a memory span of three seconds.
5. A male angler fish attaches itself to a female and never lets it go. Their vascular systems unite and the male becomes entirely dependent on the female’s blood for nutrition.
6. Beavers can hold their breath for 45 minutes under water.
7. The sailfish is the fastest swimmer, reaching 109 km/h (68 mph).
8. The slowest fish is the sea horse, which moves along at about 0.016 km/h (0.01 mph).
9. The heart of a blue whale is about the size of a small car.
10. The tongue of a blue whale is as long as an elephant.
11. The largest jellyfish ever caught measured 2.3 m (7’6”) across the
belly with a tentacle of 36 m (120 ft) long.
12. Fish and insects do not have eyelids - their eyes are protected
by a hardened lens.
www.whereincity.com

About World Water Day

International World Water Day is held annually on March 22 to focus attention on the importance of fresh water and advocating for the sustainable management of fresh water resources.
An international day to celebrate fresh water was recommended at the 1992 United Nations Conference on Environment and Development (UNCED). The United Nations General Assembly responded by designating 22 March 1993 as the first World Water Day.
Each year, World Water Day highlights a specific aspect of fresh water. This year’s theme is “water and food security”.

Published on LakbimaNews on 25.03.2012 

Reversed roles in International Women's Day --> Will Male Mantises, Spiders protest for Equal Rights?

A few weeks ago we were all shocked by the news that a new bride had been killed by the groom while on their honeymoon. However to mantises andsome spider species, this kind of thing is rather a fact of life - the male sacrificing its life during courtship to the female partner. In contrast to behaviour in human society, it is not the female that ends up being the victim, but the male.

Human society is male dominant, but in the case of mantises or spiders it is the reverse. The female mantises are many times larger than the male. When the time comes to mate, the male mantis approaches the female carefully. He flaps his wings, sways his abdomen and makes a few circles around the female. Then copulation begins. Leaping on her back, he begins to mate. But this is often the male’s last act. While the male is busy making love to its partner, the female tears off her unwary male’s head. The female mantis eats the head of the still-mating male and then moves on to the rest of his body.

Mantises are formidable predators. They have triangular heads poised on long necks (elongated thorax). Typically green or brown and well camouflaged amongst the greenery in which they live, mantises lie in ambush or patiently stalk their quarry. They use their front legs to snare their prey with reflexes so quick that they are not visible to the naked eye. Their legs are further equipped with spikes for snaring prey and pinning them down.

The Praying Mantises got their name on account of their prominent front legs, which are bent and held together at an angle that suggests the position of prayer. But though they seem cultured and in prayer, the females are by no means virtuous. “If you put a pair together and come back later, you’ll just find the wings of the male and no other evidence he was ever there,” say researchers who investigated this interesting phenomena recognized as sexual cannibalism. Sexual cannibalism has fascinated biologists ever since Darwin. It is not limited to mantises, but is also found in other invertebrates, including spiders, midges and perhaps horned nudibranchs.

Honeymoon widows

This is also the sad fate of male Black Widow spiders. Black widows are notorious spiders identified by the coloured, hourglass-shaped mark on their abdomens and in fact they get their name from their habit of killing the male on first mating, leaving the female a ‘widow’. Female black widows mostly feed on their male partners after mating. The females are bigger than the males and also contain more venom, which is at least three times more potent than that of the males’, research reveals. Thus, even if a male bites the female in self-defence, on being bitten by the female, he would succumb to his death more rapidly and is therefore more likely to be eaten.

In fact the spider’s bite is much feared because its venom is reported to be 15 times stronger than a rattlesnake’s. If a human is bitten, he/she will expereince muscle aches, nausea, and a paralysis of the diaphragm that can make breathing difficult. However, contrary to popular belief, most people who are bitten suffer no serious damage, let alone death. But bites can be fatal to small children, the elderly, or the infirm. Fortunately, fatalities are fairly rare; the spiders are non aggressive and bite only in self-defence, such as when someone accidentally sits on them. So the male black widow doesn’t stand a chance at all, if a female bites it.

To feed, black widows puncture their insect prey with their fangs and administer digestive enzymes to the corpses. By using these enzymes and their gnashing fangs, the spiders liquefy their prey’s bodies and suck up the resulting fluid. These spiders spin large webs in which females suspend a cocoon with hundreds of eggs. The spiderlings disperse soon after they leave their eggs, but the web remains. Black widow spiders also use their webs to ensnare their prey, which are mostly flies, mosquitoes, grasshoppers, beetles and caterpillars. Black widows are comb-footed spiders, which mean they have bristles on their hind legs that they use to cover their prey with silk, once it is trapped. You will be relieved to know black widow spiders are found only in America and Australia.

Some other species of spiders such as the red-backed spider too shows this sexual cannibalism and also the horned nudibranch which is a mollusc which lives on the sea floor. Human scientists who are from male dominant societies still debate on why this kind of strange behaviour evolved in these species. There are several theories and most scientists believe that the voracious appetite of the hungry females lead to the cannibalism. The males are vulnerable at the time of mating and the hungry females don’t waste a chance to change their honeymoon beds to dinner tables. But experiments have also suggested that it is a strategy that females use to select the best fathers for their offspring.

Monogamy to the extreme

In some cases, sexual cannibalism may characterize an extreme form of male monogamous behaviour, in which the male will sacrifice itself to the female. Males may gain reproductive success from being cannibalized by either providing nutrients to the female (indirectly to the offspring), or through enhancing the probability that their sperm will be used to fertilize the female’s eggs.

Some zoologists also propose the theory that males too played a role in the evolution of sexual cannibalism by surrendering themselves to the female. They believe this act of submissiveness increases male reproductive success, as their bodies nourish the mothers of their offspring, raising the odds that those offspring would successfully hatch and grow up to produce their own offspring, thus carrying on the father’s genes. Research has also revealed that cannibalized males father twice as many offspring with a female that mates with other males. In this perspective, it can be considered as the ultimate fatherly sacrifice.

Scientists also say that cannibalism provides the males, extra time to put a plug in a female’s sperm receptacle. Researchers have also made an interesting observation of the orb-weaving spiders where the males suddenly die, as they mate - the male’s death may be a strategy for preventing other males from mating with the female as in death, its sexual organ becomes stuck in the female’s receptacle. Even if she feeds on the rest of his body, the organ remains, preventing further breeding.

It is believed different species could have different reasons for preying on the mating male. Scientific research reveals that all of the above reasons could be true. Whatever the reasons, these male mantises and spiders sacrifice themselves on their honeymoon night. So if human society can dedicate a day to the cause of betterment of the female, then perhaps the males of the mantises and spiders should form a few NGOs, protesting to initiate a day dedicated for males in their society. Don’t you think?

Insects in the Zoological Gardens

Insects conquered the earth before humans, and still are one of the largest groups of animals on earth. There are many interesting insects and many of the modern zoos have a separate section to showcase this amazing world of insects. These insect zoos are in addition to butterfly gardens that are an attraction in many zoological gardens. The insect section of the Malaysia zoo set up recently is a refuge for over 200 species. Mantises, stick insects, tarantula, scorpions, Madagascar’s hissing cockroaches are some of the insects that are the usual attractions and are kept in these insect zoos.

Dehiwala Zoo has a butterfly garden which is still under repair and this also used to have a few leaf insects and stick insects other than butterflies, in its glory days. Let’s hope once the repairs are finished, we will once again get a chance to observe interesting butterflies and other insect

Published on LakbimaNews on 18.03.2011

Scavenger sage-named

The zoo is also home to many interesting raptors: birds that hunt other animals. This week, ZooLander reports about the Brahminy Kite - one of the most common Raptor species in our country, often found abandoned in the zoo -- both in captivity and free ranging.

In ancient India, the Brahmanas were a common sight. Even when the Europeans invaded that country, there were Brahmanas who were dressed in a reddish-brown cloth wrapped around their bodies. The European invaders fought to capture these areas; no sooner things got settled, they started observing the strange new world they had stepped into. They first found the Brahmanas who were meditating in the jungles dressed in reddish-brown clothes. Then came the ornithologists; almost all of them were nature enthusiasts, even military officers and administrators would  spend their  time looking at the sky during their leisure times.  It didn’t take long for these ornithologists to note the reddish-brown patches that soared high in the sky.

Beautiful raptors
Observing more closely, they realized these to be beautiful raptors, with colourful wings, similar in colour to the reddish-brown clothes of the Brahamanas. Legend has it, that it led to this bird of prey being named the Brahaminy Kite. Another theory says that this bird is being treated as a sacred symbol by the Brahmin cast of India, and hence it was named Brahminy Kite.
However, the Brahminy Kite is also considered a contemporary representation of Garuda which is a sacred mythical bird in Hindu legend. Hindus believe Garuda is the vehicle of God Vishnu, and is depicted as having a golden body of a strong man, a white face, red wings, and an eagle’s beak -- complete with a crown on its head which are most of the characteristics of the Brahminy Kite. The Garuda, the ancient deity, is said to be a massive bird that is even large enough to block out the sun.
No matter how the bird got its name, Brahminy Kite is a beautiful bird which has a  distinctive and contrastingly coloured reddish-brown or chestnut coloured plumage, a white head and breast, with black wing tips. The juveniles are brownier when young, but acquire the normal coloration no sooner they reach adulthood.
Brahminy Kite is a master of adaptation that has managed to adjust to the changes in the environment and survived even in busy populated cities such as Colombo. Today, Brahminy Kite is the only medium sized raptor one can observe in the city of Colombo. Its secret also lies in its feeding habit being primarily a hunter; but it can also survive by scavenging and birds commonly found in large numbers, in mass waste dumping sites.

Brahminy in the Zoo
Right - you can see them in the sky flying at a distance. “But where can I see a Brahminy Kite closer... or where will I get a chance to go so close and touch one of these majestic birds..?” you may ruminate. Without any hesitation, ZooLander recommends that you visit the Dehiwala Zoo to have a closer encounter with the Brahminy Kite...
The Brahminy Kite enclosure is located at a far corner of the Zoo. There are a couple of Brahminy Kite pairs in this cage and their unmistakable scream -kweeaa or kyeeer, when active, can be heard at a distance.

Kids’ Corner
But at the zoo you can also have a more intimate encounter with a Brahminy kite, if you visited on a week day or on a Saturday,  the ‘Kids’ Corner’. In the zoo, have you noticed that there is an area dedicated to  children..? Known as ‘Kids’ Corner’ this is where some of the tamed animals are taken out and allowed to interact with children, under the guidance of members of the Young Zoologists’ Association. A Brahminy Kite too is also often taken out to this open area in the Kids’ Corner allowing the Zoo visitors and especially kids to have a one on one encounter with the beautiful raptor. Some of the brave kids also dare to touch the eagle and a gentle touch without hurting the bird is allowed. But remember, touching overly can amount to harassment; everyone is advised to careful not be a nuisance to this cute Brahminy          Kite.
Brahminy Kites are not saints as their  names denote, as they actively hunt for prey. They hunt small prey such as fish, crabs, frogs from water and rodents (mouse, squirrels), reptiles on land etc. Scanning and hunting for food using their eagle eyes, the Brahminy Kites forage both over water and land, soaring 20-50m above the surface. When they spot prey, they descend fast and snatch the prey using their sharp talons. Brahminy Kites don’t dive into the water, but can skilfully pick the fish that come onto the surface unaware of the danger lurking in the sky. They eat their food on the wings. However, in the zoo they do not need to kill animals as they get a free meal everyday. Brahminy Kites in the zoo are usually given a fish diet.

Major scavenger in the city
However, as mentioned earlier, the Brahminy Kite is also a major scavenger in the city, garbage dumps being their favourite ‘restaurants’, a habit which has helped them survive even in populated areas. In Colombo, too, you can find a number of Brahminy Kites near garbage dumps. Sometimes over 30 Brahminy Kites can be seen hovering above, looking down to pick carrion  or an unwary mouse that comes to feed on the dump. In natural areas, it is said that the Brahminy prefer mud flats.

Brahminy Kites are also aerial acrobats, mate on or near the nest, its breeding season in South Asia being from December to April. The Brahminy Kites build bowl shaped nests, usually on top of large trees. Both parents take part in nest building, using small branches and sticks, lining the nest with leaves. They like to build the nests closer to a good food source, such as a water body where they can catch fish in abundance to feed the young -- or a good dumping ground where they can scavenge easily. Brahminy Kite eggs are dull white or bluish-white and are oval shaped. Brahminy mothers often lay a clutch of two eggs. The mother Kite has to incubate these eggs for about a month and both parents take part in feeding the hungry fledglings.
Juvenile Brahminy Kites have a different plumage often displaying a uniformly dark brown plumage, white parts streaked with buff. In flight a pale patch at base of primaries is seen and it is difficult to distinguish these juveniles, from the Black Kites (which have square tails) and immature White-bellied Fish Eagles.

Brahminy Kites are found in many parts of the world including the Indian Subcontinent, Southeast Asia and Australia. Known as Elang Bondol in Indonesia, the Brahminy Kite is also the official mascot of its capital city, Jakarta. In Australia, the Brahminy Kite is identified as Red-backed Sea-eagle, perhaps because they are not familiar with Brahmanas and do not associate the colour similarities.

Brahminy Kite is not a threatened bird species; however their populations are  declining in some areas. It is their adaptability to city life which gives them a lifeline and helps in their survival. At your next visit to the Zoo, take a closer look at the Brahminy Kites.


Published on LakbimaNews on 11.03.2012

Motherly love of a savage beast

Crocodiles are seen as ruthless killers lurking in the waters ready to attack humans. People also say that they are so ruthless that the mother crocodile even feeds on its young. Are crocs that savage?
Two weeks ago, ZooLander reported about the giant crocodile which was killed because it hunted a man that went near the marsh it lived in. Human-crocodile conflict has existed in many areas, with occasional attacks unfortunately tagging these aquatic reptiles as ruthless man-eaters.
‘Crocodile mothers are so blood thirsty, that they eat their young just as they emerge from the eggs’ is something most people believe. There are many who say they have witnessed croc mothers eating their young. Yet even the most menacing creatures in the animal kingdom usually care for their young. So what made crocodile mothers so ruthless?
There is a saying which goes ‘the eyes don’t lie’, but if you do not observe everything closely, even what your eyes see can be deceiving. It was herpetologists who first observed that crocodiles do not eat their young. Crocodiles being held in captivity helped inmaking this observation. What people see as croc moms trying to eat their young is in fact them carrying them in their mouths to a more secure place.

The young are vulnerable, that’s why they got mommy
Crocodiles usually build their nests on the bank of a river, or near a lake, an area where both land based and water based predators lurk. Though crocs are one of nature’s deadliest animals, their babies are still vulnerable to predation. This gentle act by crocodile mothers most definitely help save the lives of lots of their young for sure. And though they carry their babies in their mouths, they are ever so careful not to bite them. Like a cat moving its cubs to safety by lifting them from the skin of their necks carefully, croc mothers too take extra care not to close their deadly jaws while the babies are inside.
Scientists also believe there is chemical recognition between mother and juveniles, so she can recognize her own offspring and the young crocs also use several types of calls to communicate with the mother crocodile to solicit her protection. However, the young crocs are fair game for other adult crocodiles! The female will try to defend them, but quite a few crocodiles are eaten by larger crocs before they reach maturity. Scientists say this cannibalism actually serves a purpose - when populations are healthy, and there is no need for large numbers of juveniles to enter the population, their mortality is very high. However, if the population is low and needs to recover, the survival rate of the juveniles becomes much higher and many more survive to become adults. It’s a tough life being a crocodile!
This journey into the water, caught between jaws with a series of sharp teeth, would definitely be a memorable first tour in life, for croc babies. But this act is not the only behaviour that shows the gentle, caring side of a crocodile mother.

The importance of temperature
First of all, the crocodile mother ensures her babies get a comfortable bed until they are hatched. Croc mothers usually build a mound from vegetation and mud, and then dig a hole at the top, into which they lay their eggs before covering them over. A clutch of eggs can have as few as 8 eggs and as many as 80. Crocodile eggs take about 85 days, or almost 3 months, to incubate.
There is also amazing findings which say, that the sex of the embryos of the eggs, are decided by the temperature to which they are exposed in the nest. Scientists have found that crocodile embryos do not have sex chromosomes, and unlike humans their sex is not determined genetically, but by temperature. If the eggs are exposed to a temperature of around 31.60C (890F), these eggs will turn in to male crocs while the females are produced at slightly lower and higher temperatures. The decomposing vegetation in the nest mound provides warmth to the eggs, while the mother stays close by, guarding the nest site.
Guarding the nest is not a habit prevalent in other reptiles, which just lay eggs and moves away, leaving the babies to survive on their own. However, unlike other reptiles, crocodile parental care doesn’t stop there. The mother will guard the nest until the eggs are ready to hatch. Then when she hears the babies (called “hatchlings”) calling from within their eggs, she will open the nest and help them come out. Mother crocodiles will sometimes help the babies hatch by gently cracking the eggshells in their mouths.
The baby crocs form a ‘crèche’ - a small group that the mother will defend vigorously. Not a bad mother to have, you might say! Eventually, after several weeks or months, the juvenile crocodiles split up and disperse to try and find their own habitat, saying good bye to their beloved mother that had taken care of them, so very well.

Love even in captivity
There are facilities, similar to zoological gardens, that are specifically made for crocodiles. The most famous one is the Madras Crocodile Bank located in India. However Zoolander also found an interesting research conductede by the St. Augustine Alligator Farm in Florida, USA. They usually separate the eggs once the mother croc lays them in the mound nest, and hatch them in artificial incubators. But when they let a mother take care of its young instead as part of the study process, they reapedsome very interesting results.
They had selected a Siamese crocodile for this experiment in the year 2000. One week after the eggs were laid, the zoo based researchers gently opened the top of the nest and checked the condition of the eggs. After they allowed the eggs to hatch naturally, one morning 7 weeks later, they had noticed the mother croc lying on top of the nest. Her head was cocked sideways, seemingly listening.  After the lapse of an hour the hatchlings began coming out of the nest. As the zoo researchers watched, the female slowly used her front legs to pull dirt away from the top of the nest. When she uncovered a hatchling, she gently picked it up in her mouth and carried it to the water.  If she uncovered an egg that was not yet hatched, she gently broke the egg with her mouth, scooped up the baby and again carried it to the water. Sometimes the hatchlings were still attached to the egg by their yolk and both baby and egg would be carried to the water.  One little guy had quite a struggle - the egg he was attached to started to fill up with water and began to drag him under.  He was pulled partially under water before he managed to wiggle his way free.
All this goes to prove that zoos too can be used easily, to research the behaviour of animals. The Colombo zoo too, will soon provide many opportunities to study the behaviour of the animals in captivity, with the aim of relating these behaviours to animals in the wild.  Research, in fact, opens our eyes to the real situation, as in the case of crocodiles.
Many of us believed that crocodiles were just ruthless blood thirsty man-eaters, but they are as gentle as human moms, when it comes to parental care. True, they are dangerous animals in their territories, but let’s not make outcasts of them and have a grudge and kill them whenever a crocodile is sighted.

Published on LakbimaNews on 04.03.2012