Boost for conservation:

Dehiwala Zoo, a future research platform

By Dhaneshi YATAWARA

At times nature acts and reacts in very strange and eccentric ways. Nature would lead a mother to reject her offspring. It was this decision of Mother Nature that led to the tragic death of the week-old male Bengal Tiger cub of the Dehiwala zoo almost a week ago.

National Zoological Gardens Director Bashwara Senanka Gunaratne	Veterinary Surgeon Jagath Jayasekara

According to veterinary surgeons of the Dehiwala zoo, the cub was gaining 60 grams of weight per day and was weighing a little over 1.2 kilograms at the time of its death. The post-mortem on the Bengal Tiger cub gave respiratory failure due to acute pneumonia as the cause of death.

National Zoological Gardens Director Bashwara Senanka Gunaratne said further tests would be carried out to determine the reasons which caused pneumonia.

The cub’s lungs and several other tissue samples have already been sent to the Department of Veterinary Science of the Peradeniya University for further investigations. The week-old Bengal tiger cub died on November 29 at the Dehiwala zoo.

“Its condition started worsening from Friday morning and it was showing difficulty in breathing,” said Veterinary Surgeon of the Department of Zoological Gardens at Dehiwala Jagath Jayasekara. “We gave oxygen to the cub and nebulised it when it was experiencing breathing difficulties,” he said.

What made the Bengal tiger mother reject her cub?

“There are three ways in which animals reject their cubs. These three are phenomena identified across the globe. Firstly, some animals reject feeding and caring for the cub from its birth.

“Secondly, the mother rejects the cub after feeding it for a few days and thirdly, the induced behaviour pattern of the mother animal would lead her to reject the cub,” Veterinary Surgeon Jayasekera said.

He explained that an elephant mother would reject its calf if it observes that the baby will be unfit for survival in the natural environment. “It is observed that in such instances the calf will be kept away from the herd and left to die in the wild and in certain instances they would even go to the extent of killing the calf”. According to him, carnivores tend to reject their cubs more often compared to herbivores.

Hamadryas baboon

The employees of the Zoological Gardens are raising the baby Hamadryas baboon, Sheila which was rejected by its mother from day one.

Fishing cats

“The mother baboon actually tried to kill the cub by dipping it in water, but we saved the baby after tranquillising the mother,” Jayasekara said. Now it is eight months old and growing healthily in the zoo nursery.

The Bengal tiger cub was rejected by its mother from birth. It is believed that the mother, with her natural instincts, would identify congenital abnormalities of the cub. Nature would not support carrying the weak gene pool to the next generation, resulting in only the fittest surviving.

A mother animal would reject the cub after feeding it for a few days due to two reasons.

Milk is not produced in the mammary glands of some animals and in others its glands do not release milk.The mother’s behavioural factor is also important. Animals depend on the lessons learnt in their lives. A mother animal would always depend on its previous experience in bringing up its offspring. “In this case, we suspect the mother’s rejection is a behavioural factor where she depends on her previous experience,” said Jayasekara.

The female Bengal Tiger gave birth to three cubs on June 10, 2010. All three had external physical deformities, especially in the limbs. With her natural instincts the mother rejected the babies. Though the zoo veterinary doctors and employees tried to raise them, the cubs died within four days.

“The post-mortem revealed that the cubs had deformities in their internal organs such as the liver which in medical terms is referred to as congenital abnormalities,” Jayasekara said. “It is quite common in captive breeding that certain females reject cubs,” he said. It is one of the greatest challenges in captive breeding for animal conservation.

By nature, a mother would reject feeding the cubs for three reasons, disturbed and unsafe environment, congenital abnormalities of the new-born and behavioural disorders,” Jayasekara explained. As the female tiger had a calm and safe environment for her delivery, the cub showed no external deformities at birth and the only negative point was her experience during her previous delivery.

Mother’s milk

Another major problem the cub faced was not being able to consume its mother’s first milk which is called colostrum. “A baby, including humans, should receive this milk as it gives the mother’s immunity to the baby against possible diseases”.

Hamadryas baboon

As Jayasekara explained the critical period of a cub would be the first week. “If the mother feeds the cub during this period, the animal would get colostrum from the mother, making its immunity stronger against infections from the external environment,” he said.

“In many instances, we had raised offspring which were rejected by their mothers after feeding them for about a week. Raising such babies is easier,” he said. If the mother rejects the baby from day one we find a foster mother, he said. In two separate instances in the past, the zoo had to raise a Fishing cat and a Rusty Spotted cat using lactating cats as foster mothers! “If the rejected cub is of the size of a kitten we can train the mother cat to feed the cub, accepting it in to her litter,” he said. When the cub grows a little bigger, they bottle-feed the animal. But the Bengal Tiger cub is the size of an adult cat.

A foster mother was an impossible alternative and bottle-feeding had to be adopted. A milk formula especially recommended for the cat family was given to the Bengal Tiger cub. It costs around Rs.1,500 per 250 grams. “We took every measure to minimise the indigestion condition that normally occurs in a cub due to artificial milk.”

The cub was raised in a separate room under strict conditions as a precaution against its weak immunity system.

It was fed every three hours with the special milk formula. It screamed at the top of its voice, demanding the rich milk portion when feeding time was near. It loved all the pampering it got and was very much spoilt! It was a rare and precious moment for Sri Lanka to contribute in our best possible way to protect an endangered species of the world. Yet all within the rules of Mother Nature!

Indonesian advice

The Thaman Safari Park in Indonesia supported the Dehiwala Zoo during the Bengal Tiger’s pregnancy period and delivery of the cub and is still giving expert advice on Bengal Tigers.

This safari park carries out one of the best projects in the world in conserving a sub-species of Bengal Tigers (Sumatran tigers). This breeds Bengal Tigers, then release them in to the wild.

Rusty Spotted cat        Pix : Thilak Perera

“Expert consultant doctor Retno Sudharwathi advised and guided us from the beginning. They faced many such challenges in their work and their assistance will be a great support during critical moments we face in the future,” Jayasekara said.

“What we used is one of the best standard milk formulas used in captive breeding to raise cubs. We will keep adequate stocks ready for similar circumstances in the future,” the Director of the Department of Zoological Gardens said. The Department had bought a special automatic steriliser to clean and sterilise the bottles. “If we try to dry the milk bottles and all the equipment by hand contamination is possible. So this is safer,” Gunaratne said.

With the birth of the cub the zoo identified many possible growth areas. “We will be maintaining records of each and every animal and we will be computerising them,” he said. “We need to raise the level of the zoo to a good research platform to provide services to local and international scientists involved in conservation,” Gunaratne said.