On Friday, 6th November 1998 a curious event happened at Glasgow Zoo which has us all puzzled, but a Veterinanian somewhere might be able to explain, hopefully in great detail what has happened.

Ayeesha , our six year old Indian Tigress gave birth to two cubs. "Nothing strange about that" you might say, except that Ayeesha had been heavily in oestrus some five weeks earlier for a full week. When zoo keeper David Hughes, Head of the North Section informed me of this at the time, I was so puzzled - believing Ayeesha to already be eight weeks pregnant - that I made a point of going to see for myself.

She appeared to be a full oestrus, exhibiting lordosis, soliciting mating from her mate Butu , crouching, holding her tail to one side, and indeed carrying out full mating. I, in common with the rest of the staff, then assumed the previous foetus ( if any ) had been re-absorbed or the previous oestrus had been unsuccessful ( a not uncommon occurrence ). Although, this would have been Ayeesha's third litter ( previously having had one at Dublin, and one here !)

Ayeesha and her mate Butu are in a large heavily planted enclosure, about half a hectare in extent with a large, three compartment house with underfloor heating. One end consists of a display cage some 4 metres wide, by 6 metres long, and 2.5 metres in height. All interconnecting doors were open at the time ( although we feed the two tigers separately, to prevent squabbles ). Ayeesha had plenty of opportunity to remove herself to the cubbing den, or even to a quieter corner. Instead, she chose to give birth amongst hay on the one metre wide sleeping platform along the rear wall ( some 1.2 metres above ground ), and with Butu present in the vicinity.

Butu seemed to be well aware of what was going on, though not interfering in what was a fairly bloody experience. He has subsequently been jumping up onto ledge to sit next to Ayeesha as she nursed the two cubs, and briefly nosing at them. Ayeesha has exhibited no nervousness at all, so we decided to leave well alone and so far - Sunday 8th November, 1998 - so good.

Both cubs seem well - though noticeably smaller than her previous cubs. Ayeesha is used to Butu being present with the cubs - and he them - although we were careful only to introduce him very, very carefully on the previous occasion and even then only when the cubs were about twelve weeks of age.

Apart from all the behavioural observations, the internal biology is fascinating and demands explanations, which we hope will be rapidly forthcoming. Is it possible that all developments took place in one branch of the uterus, permitting the other to apparently cycle normally? Is there anything developing there at the moment? Or, has it been suppressed as logic would suggest?

It is interesting to note that David Hughes tells me that two weeks ago in the third week of October, Ayeesha appeared to be on oestrus again, though this time for only a few hours perhaps a day or so.

Cub Update: 25/11/1998

Peter Kerr M.R.C.V.S., Zoo Veterinarian of

At the time of writing, the tiger cubs are 2 weeks and 4 days old. All is well, quiet and settled. Ayeesha the female, as one or two e-mails predicted she might, came into oestrus on Monday 23rd and for a short time on the 24th. She was mated on several occasions by Butu , the male, without any undue stress, or frustration evidenced in the male..

Peter Kerr agreed with our actions and general interpretations, whilst he was away. He believed there was almost certainly a uterine problem with Ayeesha . He explained that tigers; being a cat, exhibit an induced oestrus - ovulation being triggered by mating or the presence of the male.

Butu is a quiet male, who never harries or harasses the female, so the suggestion included in a couple of e-mails that the pheromones produced by a randy male could induce oestrus, was unlikely because Butu is not particularly randy.
" If anything, she is the randy one!! "

Peter Kerr has recommended the acquisition of calf's milk because of worries that the production of extra oestogen during oestrus might affect the supply of milk for the cubs. He does not want the cubs removed, nor bottle fed. Just the offering of bowls of this milk as a supplement if/when this becomes necessary.

He is a bit concerned if Ayeesha continues to come into oestrus regularly from now on. Normally oestrus would be suppressed until the cubs were about 2 years of age, and facing independence (earlier if the cubs were removed for any reason, or they died).

What should be emphasised, and indeed Peter Kerr explained this again himself, is that normally we would have separated the female into her cubbing den, and separated the male, perhaps as early as 10 days before cubbing was due. That we did not on this occasion was because we were fooled by the lengthy period of mating 6 weeks before the birth, causing us to commence the count-down all over again.

That we are now able to witness everything in such detail is by a combination of good fortunes.

• Firstly, the female gave birth and is nursing her cubs in the public exhibition den, in full view.
• Secondly, she is completely unconcerned by people watching her, partly because she is separated by a 25mm thick laminated glass which is almost sound-proof.
• Thirdly, Butu , the male, is very quiet, and non-aggressive.
• Fourthly, the female has bred before here, so is experienced and trusting with the staff and surroundings etc.

Peter Kerr has pointed out that in due course it may be necessary to address Ayeesha's suspected ovarian problem. If this was a cow, there is an injection which can be applied which reduces, or eliminates any cysts or similar malfunctions. However, this has never been tried on a carnivore, but might well be worth a try on this occasion, if it can prevent the necessity of invasive surgery or worse, a hysterectomy. However, this is probably some way off and the likelihood, or otherwise, will be determined by the behaviour of Ayeesha and Butu .

What we definitely will not do, unless there is absolutely no alternative, is remove the two female cubs for hand-rearing on the bottle. That would be the easy and old-fashioned approach. Supplementary feeding is more subtle, and permits us to continue to observe this unique scenario.

It must be emphasised how unusual this is.

Normally, the cubs would have been born inside a dark cubbing box. Not only would we not have been able to observe every detail of the family's domestic routine, I and most of the staff would not have seen them until they were about 4 weeks of age. Then they probably would not have been on show to our visitors until they were 6 or 8 weeks of age (or until Ayeesha moved into the display cage.) Then they wouldn't have normally been introduced to Butu until they were about 10 or 12 weeks of age.

To have all this unfolding in front of us, no more than 2 metres away, is a beautiful, uplifting experience which I for one have never seen before, and I don't expect to witness this behaviour again in my lifetime.

Tigers have given birth before in public view, and with the male present, and this has usually ended in disaster because the female was not prepared for the birth, and was stressed. The cubs were either eaten, or were trodden upon and died, or were continually carried around by a distressed mother etc.

For probably hundreds of years, and certainly all of my working lifetime, it had been the popular zoological keeper's perception, worldwide, that male tigers killed newly born cubs when they encountered them. Recent researches in the wild are suggesting that this is not so, with males taking a paternalistic view of their cubs.

• Could it be that the misconception has arisen because male tigers in the wild have been observed killing young cubs which were erroneously assumed to be their own cubs?
• What if the cubs had been sired by another male, and the male was just mirroring the behaviour that we have become so used to ( and had comprehensively explained, in the African Lion )

In remote country areas in Scotland, it has long been believed - indeed I have seen it written down more than once - that where a Scottish wild cat fathers kittens by a domestic cat, he will return when they are a few days, or weeks old, and kill them.

Could this not be a similar scenario, where another male - not the sire - is doing the killing, and for the same sub-conscious, jealous-gene, reasons?

Tiger Update 29/11/1998

On Monday, 23rd November 1998, Ayeesha came into oestrus and mated many times during the day. As Ayeesha and Butu , her mate, have unrestricted access to all three rooms of the Tiger House, and the one acre of heavily planted, outside enclosure, at all times, most of the matings took place outside and well away from the cubs.

It should perhaps be emphasised just how fortunate we believe ourselves to be in that Ayeesha chose, voluntarily, to give birth to her cubs, then nurse them, in a corner of the main glass-sided display cage, some two metres from onlookers. Strangers and keepers alike, watch through the glass. If she had so chosen, she could easily enough have retreated to an off-exhibit cage, with more privacy. That she did not, has presented us with unrivalled opportunities for observation.

The fact that Ayeesha came into oestrus 2.5 weeks after cubbing, confirms the initial diagnosis of a possible cystic uterine, or ovarian disorder.

Dr D. Magnus Nicolson, of Glasgow's West of Scotland Science Park has summarised Ayeesha's situation as follows:

During pregnancy, the Cell Mediated Immune System is down-regulated in order to prevent rejection of the foetus. At this time the body's tumour surveillance capacity is therefore also diminished. Now that your tiger has given birth, I would expect an increase in her immunocompetence. If the hormonal dysfunction that was observed was a result of a cyst it is possible that her own immune system may be able to deal with this growth if it is small. Let's hope this is the case..

Certainly, our vets too have decided to follow this course of action in the hopes that Ayeesha stops cycling , thus denoting a normal situation having been restored.. Again, perhaps it should be emphasised again, that it was Ayeesa's week-long oestrus mid-way through her 90-day gestation, that confused us, resulting in Butu still being in the same enclosure when the birth took place, permitting the resulting observations to be made.

In mid-week, after two weeks of taking soundings and opinions, largely via e-mail discussion lists and our web-site, we released a comprehensive Press Release accompanied by a Broadcast Quality, professionally made video.

It was interesting how people invited to comment tended to home-in on their particular area of interest or expertise. Peter Jackson, of the Cat Specialist Group of I.U.C.N. , the International Union for the Conservation of Nature, concentrated on the behavioural aspects. He confirmed both that cub killing by males in the wild, was likely to be the cubs of rival males, and stating his belief that improved standards in zoos was probably resulting in more of this behaviour becoming possible, because the tigers were less stressed . [Times ].

Another Keeper of a Zoo in the South of England with many tigers said that when a female gave birth with the male present, she was " easily able to fend him off. " It must be emphasised that there was no question of Ayeesha fending Butu off on this occasion. It appeared just like an exercise in co-operation, and still does.

It is probably significant that this is Ayeesha and Butu's third litter together, and that Butu is an easy-going, placid male. We would probably continue to recommend the utmost caution for the first litter, or allow it to take its chances and be prepared for failure and possible injuries. However, this is by no means inevitable, particularly if the dens are sufficiently large and private to permit the male and female to choose where events take place, and whether or not they needed to interact or stay out-of-the way.

When we decided to release the story to the media, we used an agency, on this occasion Press Team Scotland who can be contacted at:

The still photographs, and the video took several visits to make (largely because it took some time for the realisation to dawn that the family shots of Butu and his mate, and cubs all cuddled in together, could only be obtained first thing in the morning, because they all slept together. Butu lying across the corner, Ayeesha alongside, and touching him, and the cubs at right angles suckling her. By 9 am Butu was up and strolling around outside, and whilst he regularly popped into the dens, especially if something was going on, and there were visitors about, and interacted with the cubs, he could not be photographed in the glorious en-famille situation depicted here, until the following morning.

This was one of the main reasons we wanted a video made, as normal TV news film would just use what they secured in the mid-afternoon say. Yet we felt it important that the body language of the early morning was able to be portrayed and would be of considerable interest to zoologists and zoo keepers world-wide if we could record it.

We have now sent a copy of the video down to a bog London agency that specialises in the USA Market, and are hopeful that an edited version will be transmitted coast to coast in the coming week in the USA.

On Thursday the 27th November 1998, the story and stunning colour photographs were carried by

• The Times,
• Glasgow Herald,
• Scotsman,
• Daily Record,
• Scottish Daily Mirror,
• Daily Express,
• Daily Mail

Most people, and those invited to comment, focussed on Butu's egregious behaviour. However, it must be emphasised that had it not been for Ayeesha coming into oestrus whilst already pregnancy, we would have been fully prepared for the birth, with Butu separated some days previously.

Ayeesha's physical disorder will lead directly to a complete change in our management of this pair of tigers when they give birth, if they give birth again, or are allowed to give birth again.

If the biological explanation is, as is suggested by Dr Magnus Nicolson, then there seems no reason from a veterinary point of view why Ayeesha should not be allowed to have another litter. If it is not, then a hysterectomy, or the removal of an ovary is another possibility at the other end of the spectrum, and something we would obviously seek to avoid if at all possible.

On Thursday, I was approached by the wife of a friend who had come to the zoo specially to see the cubs. She said: I was interested in the description of Ayeesha's condition. When I was pregnant with my son, and she pointed at her three-year-old. The Doctors said I had a cystic ovary too. After he was born, it just went away of its own accord.

Tiger Update, 3rd December 1998

Both cubs are growing well, and are clearly receiving sufficient milk in that, after suckling, and/or when the mother gets up, they both roll over asleep.

They are both mobile, creeping about from den to den. (really room to room). Their hind legs are still wobbly and they creep along - crouching. The mother keeps lifting them back, to what she clearly considers as the favoured den site, just inside the door of the display cage, about 2.5 metres from the windows. These dens were carefully designed, so that the tigers could see out whilst lying down on the warm concrete floor (underfloor heating). The windows come down to 12 cms above ground level. Ayeesha clearly enjoys suckling the cubs whilst being able to see out in several directions. Judging by the two front paw marks, on the window ledge on the outside, a passing badger, took the opportunity of standing on his hind legs to look in (either attracted by the high pitched calls of the cubs, or a follower of our regular web-reports?)

One e-mail suggested that Ayeesha's repeated oestrus' could perhaps have been prompted by the pheromones produced by a randy male. Butu , is not particularly randy, however he is normal . When Ayeesha strolled out into the outside enclosure (as there is no necessity to isolate hr or her cubs, her quality of life has greatly improved, especially when compared to the six, or seven weeks isolation from the male, and thus the outside enclosure, she was previously faced with) Butu , was clearly pleased to see her, or was responding to her hormonal stimuli perhaps?

He bounded playfully to greet her, snuffling a tiger greeting, then started to sray, firstly on two fence uprights, then urinating as a large pool on the perimeter, slabbed path. The female carefully sniffed all this, exhibiting " flehmen " - the wrinkling back of her hips, and silent " snarl " with head held high, as she did so. Perhaps his pheromone levels are having a more significant effect that we had previously thought.

The final observation, is that whilst Ayeesha was out , one of the cubs, very deliberately, left the nest site and wobbled over to the far corner of the cage (about 3 metres) where there were some previously produced faeces. She then defecated, quite methodically and deliberately before making her own way back to the nest site. One can think of a number of reasons why such behaviour might be advantageous in a wild situation.

Bengal Tigers cubs thriving

As anticipated, if not almost predicted, after the birth of the cubs, Ayeesha did come into oestrus, for the first time after three and a half weeks, then again six weeks after the birth. Since then - nothing. Ayeesha was in oestrus for two and a half days, six weeks before the birth, which fooled us into thinking she was not pregnant.

Dr.Magnus Nicholson advised us that Ayeesha was almost certainly harbouring a cystic condition, taking advantage of the reduced immuno-suppression typical in pregnancy to grow and develop. He informally predicted that provided any cyst was not too large, when the immune system kicked back in after the birth, it would cause any cyst to go into retreat then hopefully disappear. He also warned that Ayeesha would almost certainly come into oestrus once or twice before this was accomplished. We are almost certain that something like this has been happening. We also regard this as a good example of good keepers observations, relayed to the management of the collection, then supplemented by outside expert knowledge, can result in the unravelling of a fascinating zoological pageant, without automatically diving to look for a Veterinary, and possibly invasive, solution, or, perhaps even worse, not even Trying to make the connection between the observations.

Because Ayeesha and Butu had ready access to the outside enclosure, nearly all matings took place well away from the very young cubs. This avoided , any possible conflict with the male - a worry of some correspondents - not that we ever saw signs of stress from him with regard to the cubs. Indeed he was often to be seen lying down inside, in front of the windows, with the cubs clambering over him, lion-style. How we wished we could have afforded a Web-Cam, so everybody could have shared this with us.