<&>Wellington Corpus of Spoken New Zealand English Version One <&>Copyright 1998 School of Linguistics & Applied Language Studies <&>Victoria University of Wellington <&>side one <&>0:54 so first of all a brief history of past attempts at captive breeding <,> perhaps the <&>1:00 first attempt and certainly one of the best documented was that made by professor a b w thomas of the university college of auckland last century <,> he started by collecting twenty nine animals from kariwa island in eighteen eighty five for the express purpose of breeding in captivity <,> even then an ignorance of basic biology was one of the main reasons for failure in his first attempt he collected twenty nine animals and brought them into captivity and obtained no result after twelve months he decided to go back to the wild and investigate whether the animals were sexually dimorphic or not he'd been told that they weren't when he went back to the wild and he dissected animals he found that this was incorrect and in fact all the animals he'd collected were male laughter he persevered and collected twelve animals that he considered were female out of the tuis colony and three years later had still <.>ob obtained virtually no success he did manage to <&>2:00 get one clutch of fertile eggs but those were dissected from a female that had just died so no naturally laid fertile eggs in his attempts he wrote in his paper and you can sense his frustration captivity would seem to interfere with their reproductive powers an effect which could hardly <.>an be anticipated with animals of so sluggish a nature laughter following these heroic attempts there were tut <.>m more attempts over the first er half of this century to breed tuatara in captivity but these attempts have been poorly documented one can speculate that they probably involved a fairly victorian approach this is the reptile house at london zoo last century where animals were literally passed placed in small glass fronted viewing cabinets er and the success of these attempts with tuatara being um abysmally <&>3:00 low <,,> since nineteen fifty two there are much better records available of the success of attempts at captive breeding and these data come from some results that tony and i collated from records available through the protected species unit of the department of conservation and also by circulating questionnaires to various zoos that we were told had tuatara in captivity to summarise over the last thirty eight years there've been at least ninety adults that have been collected for the purposes of display and or breeding in the zoo situations of these fifty two have been adults with one of each sex at least so theoretically situations where breeding could've occurred thirty four survived <,> and from these at least twenty six clutches of eggs have been laid but note that probably about a quarter were from females that were already carrying eggs when they were collected and these were eggs that were laid within the first year of collection forty three hatchlings have <&>4:00 been produced and thirty survive today but the oldest is seven years and as i mentioned earlier none has yet reached maturity <,> it might seem quite good that we have this many juveniles surviving or and this many <.>ha hatched over this time but when one looks at the potential reproductive rate of of as female in the wild these results are actually rather poor the average clutch size on steven's island which is <.>incid incidentally the population where all captive animals documented here come from the average clutch size is about ten eggs and females reproduce on average once every four years and the incubation success in nests is about forty four percent which means that over thirty eight years a single female should produce about forty two hatchlings about the total that reproduced from um fifty two pairs in captivity <,,><&>5 the table here summarises the <&>5:00 tuatara that are held in captivity in new zealand at present and there are very few overseas so these are essentially all of them there are about eight adults overseas and no juveniles as far as these go there are adult males adult females in this column and these are ones that are paired with at least one <.>oth one other member of the opposite sex we can see that there's a number of zoos that have just a single male or a single female together in fact there are four of those with some of wellington zoo's animals are just a single pair housed together and then there are some others places notably otorohanga where there are several animals in large outdoor colonies in this case four males and four females together so a total of twenty seven adults in er situations where breeding could theoretically occur <,> from these about thirty eggs have been <&>6:00 hatched from the eggs that have been laid in captivity and there are also nine juveniles at these institutions that have been hatched from eggs collected from nests on steven's island <,,> there's also a large number of juveniles now in captivity as a result of the incubation experiments that mike thompson carried out at victoria university these generated a lot of hatchlings that were distributed throughout new zealand to these er people or institutions um thirty five still remain at victoria university and the a total of eighty two are er currently alive at the moment <,,><&>4 well if we look now at some possible reasons for poor breeding success there's a number of factors that can be identified and i'm going to go on to talk about these in more detail <,> firstly um high adult mortality lack of appropriate physical cues for reproduction lack of social interactions for instance males and females have often been in pairs with just one other member of the opposite sex <,,> er improper nutrition word <&>7:00 all these factors you can deem sufficiently inappropriate conditions for egg incubation simply <,> so i'll go on to talk about some of these factors <,,><&>4 first of all high adult mortality of the ninety adults that are known to have been collected and distributed to zoos over the last thirty eight years the results for those sent overseas make rather horrifying reading half of them have been er sent overseas and of these a third were dead within one year this is a very poor rate of survivorship for an animal that has a life span in the wild of at least seventy years <,,> er <.>th <.>th the rate of um the death rate's much lower for those that were distributed within new zealand and an analysis of the records that are available which are in many cases scant suggest that acute temperature stress is likely to have been a major factor in many deaths <,> tuatara are adapted to cool temperatures and die within a few <&>8:00 hours at temperatures in excess of thirty degrees celsius and these temperatures are relatively low compared with the temperatures that many overseas institutions maintain other reptiles <,> and this is likely to have been a major factor in these deaths nevertheless it is quite possible to maintain adults for a long time in captivity if conditions are right and within new zealand there are there's at least one animal that's been in captivity in excess of thirty years <,,><&>3 um <,,><&>3 this is moving on to another possible well variety of possible reasons that could explain poor reproductive success this is the enclosure at wellington zoo it's on public display it's a glass fronted tank where just one male and one female are present it's a small enclosure so er high density high area er small area per animal and just one of each sex and it's also an indoor <&>9:00 enclosure where temperature and photo word are almost constant year round <,,><&>3 now we know from wild tuatara that they are seasonal breeders and like most reptiles it's highly likely that fluctuations in temperature play an important role in triggering various reproductive <.>e events this graph summarises changes in testosterone levels in male hormone in male tuatara on steven's island these are wild males that are reproducing testosterone is the male sex hormone and it stimulates sperm production and mating behaviour we find if we look from nineteen eighty six through to may nineteen eighty eight that there's clear annual pattern that there is a high around the time of spermiodusis which is when mature sperm are produced and at the time males are displaying the territorial and aggressive amongst each other and mating with females levels then fall low over winter and rise again in healthy males when it's when the late summer and <&>10:00 it's highly likely that er temperature is an important factor in triggering these changes <,,><&>4 and as far as social interactions are concerned during the breeding season the males become territorial they'll defend their territories from other males they'll engage in fights at the boundaries although these are rarely fatal <,,><&>4 to investigate whether <,> a <,> there might be abnormalities in testosterone cycles in captive males i carried out some sampling on animals that are held in captivity in new zealand zoos and compared those with data available from the studies on wild tuatara on steven's island er the open circles are the mean plus or minus one standard error for five to six wild animals over the following months and the captive animals where six to eight animals are in various enclosures throughout new zealand the sample over this <.>per this <&>11:00 spring summer autumn period when levels were expected to rise and then fall we didn't continue beyond this point with captive animals because the zoos became rather upset that some of their tuatara were becoming very secretive and they didn't want the sampling to continue because their animals were no longer displaying very well um <,> so we just had the data for the seven months but the interesting result is that the captive animals do show <.>norm what appear to be relatively normal levels of testosterone during summer they reach about the same maximum level and they fall again in autumn <,> there seems to be a displacement of about one month in their cycles so that they fall earlier and this is possibly related to differences in temperature er compared with that on steven's island i'm not sure of the exact reasons but that's one possible explanation <,,> in <&>12:00 separating the data for the males in captivity i separated here to those where there was just a single male by himself with one other female and those where there were at least two males in the enclosure with females and what we find interestingly <.>i is that there's no difference between the cycles they're both showing high levels during the late summer period and then falling in the autumn as one would expect so at this point no evidence to suggest any er lack of um <.>th the lack of interaction with other males is causing a depression in testosterone levels no word there <,> i also looked er analysed the <.>d the same data in terms of whether the males were present or had a had an ovulating female in their enclosure or had no ovulating female in their enclosure females only ovulate once every four years on average in the wild and this is the time when they're sexually <&>13:00 receptive so it's conceivable that in the absence of a sexually receptive female the male cycle might be impaired but we don't see any evidence of this we find that the word levels are high in both groups at the same time and show a generally similar pattern <,,><&>3 i also looked at levels of sex hormones in females and here the situation becomes a little more complicated because as i mentioned females reproduce only <.>ev every four years on average in the wild one can illustrate this reproductive cycle graphically in the following way you follow this through <.>thr november in four years these ovals represent eggs in the oviducts that are about to be laid so the female nests here in the spring she then spends about three years <,> during which time the follicles in the ovary represented by these circles are incorporating yolk so this period <&>14:00 of myophilogenesis or yolk production extends over about three years she then mates when her ovaries are ready to ovulate <&>pronounced obulate ovulate which means the eggs pass through the oviduct and get fertilised and then she carries the eggs in the oviduct and <.>sh and the shell is laid down over about seven months before she nests again <,,><&>4 obviously in in my study it was important to discriminate <&>pronounced discrimulate discriminate between females that were ovulating when we were sampling and those that weren't um <,> this is because the levels of sex hormones differ markedly depending on whether the female is is ovulating that year or not and this graph i've produced much the same figure along the top here er although it's just shown over three years because er in in these wild animals with sex hormone cycles we were unable to separate females in the later stages of yolk production into several years so what <&>15:00 i've shown here is the levels of estrodiol which is the sex hormone that stimulates yolk production and receptivity of mating <,> levels of progesterone <,> word which rises high at the time of ovulation and testosterone whose function is not entirely known but rises high at the time of mating and probably also associated with sexual receptivity possibly inhibits the <.>completi er stimulates the completion of the yolking phase and may contribute to oviduct hypertrophy as well so the important thing to note here is that levels of all of these hormones are high if the female is ovulating at the beginning of the year but not so high if the female is not ovulating <&>15:48