Transposing bodies of knowledge and technique: Animal models at work in reproductive sciences

Transposing findings: The constructive role of recalcitrant processes

In elucidating the mammalian female cycle, the timing and occurrence of ovulation and fertility in relation to menstruation were fundamental problems. One of the most notorious generalizations was on this very point. Carl Hartman, a major reproductive scientist noted its implications for clinical medicine:

Occasionally the embryologist as physiologist makes a grave error, particularly when he attempts to extrapolate from animal to man. The most serious blunder in this regard was made by Bischoff [in l853], and his misinterpretation set gynecology back three-quarters of a century. While recovering the eggs of the bitch, Bischoff noted that she bled at about the time she ovulated. Hence, he concluded that women ovulate when they undergo the menstrual flow. … The theory was adopted by the physiologist Pfluger [in l865] and was espoused by all but a few dissidents almost up to the present century. (Hartman, 1967: 2; see also Corner, 1951)

The key contribution of the first generation of American reproductive scientists was, in fact, an accurate portrayal of the human female cycle. ³

It was not only with humans that recalcitrant generalizations caused problems: another serious concern was the reproduction of ‘mundane’ species important for experimental research and organized into local breeding colonies. Herbert McLean Evans, another major 20th century reproductive scientist and co-developer of the widely-used Long–Evans rat (Clarke, 1987), offered an account of how a cherished, hypothesized presumption that species conserve physiological forms and processes was not sustained by further research:

Perhaps one of the most striking series of events in the early history of study in this realm was created by three investigations concerning small laboratory animals. The three papers were those of Stockard and Papanicolaou [1917] on the guinea pig, of Long and Evans [1922] on the rat, and of Edgar Allen [1922] on the mouse. They demonstrated that the sequence of steps in the development of the so-called ‘estrous rhythm’ could be clearly shown by the type of cells found free in the vaginal fluid. It appeared, indeed, for a time that the application of the vaginal smear method would be all that was required to segment the stages of the estrous cycle in all animals. [However, e]arly studies by Hammond [1927] in the cow, by McKenzie [1926] in the sow, by Andrews and McKenzie in the mare, and by Cole in the cow [1930] and ewe [1931] did not substantiate this optimism; the beautifully distinct changes in the vaginal lochia of small rodents were peculiar to the smaller forms. Only in the dog, as determined by Evans and Cole [1931], was the estrogen level high enough for pronounced vaginal cornification which divulges ovarian changes. (Evans, 1959: vii–viii)

Such differences across species, many of which seem counterintuitive, are not uncommon and may problematize important transpositions.

British agricultural scientist S.A. Asdell further noted that generalizations based too extensively on research on one or a few species can lead to errors:

As a consequence of relying too much upon evidence from a single species, the rat, which is easier than most to work with, some of the earlier generalizations have not stood up under further testing. For instance, prolactin was found to be the hormone that stimulates the corpus luteum to secrete progesterone. This is so in the rat and probably in many other rodents, but in those species of other orders of mammals about which we have information, LH [leutinizing hormone] is the activating hormone. (Asdell, 1977: x; see also Ramsey, 1972)

Interviews undertaken by Clarke in the early 1980s with senior reproductive scientists revealed that a quite fierce ‘pro-rat versus anti-rat’ dispute was going on, which included debates about transposing physiological understandings of rats to humans. ⁴

A more recent account of the problematics of generalizing goes beyond portraying normal or pathological physiology. Here the mechanisms of intrauterine devices (IUDs) for contraception, a technological ‘intervention’ in bodily processes, were found to be quite heterogeneous across species:

[I]n animal studies the way IUDs prevented pregnancy varied from species to species. In sheep and chickens, they blocked sperm transport; in the guinea pig, cow and pig, they inhibited implantation; while in the guinea pig, rabbit, cow and ewe, they also interfered with the function of the corpus luteum. … Similarly, research on humans has tended to show that IUDs affect ova and sperm in a variety of ways. (Bullough, 1994: 187–188)

Such research is highly charged and consequential, given the intensity of transnational debates about when life begins, particularly crystallized around abortion but also significant for many kinds of contraception and stem cell science.

Thus, reproductive scientists were vividly aware that extrapolating research results to the bodies of other species, including humans, could be highly problematic due to both inter- and intra-species differences. Yet such extrapolations were routinely made as requisite bricks with which to build a rationale for modern experimental research in general, and the reproductive sciences in particular.

Transposing infrastructures

We next analyse two historical attempts in the biomedical sciences to generalize research results from animals to humans. ⁵ Presented as useful research offerings from biologists to gynaecologists, they are analysed as claims-making ‘demonstrations’ of the generality of physiology across species’ bodies, and the consequent ‘usefulness’ of biologists’ work for enhancing the gynaecological market. Yet researchers confronted a powerful contradiction. As George W. Corner (1951: 920) noted: ‘Experiments could not be done on humans, and the use of the operating table and mortuary was limited for people do not come to those places unless they have something wrong with them and we wanted to study the normal cycle … in addition to routine abnormalities.’ Primates became the solution. Since Darwin, evolutionary proximity had made non-human primates preferred, if contentious, ‘exotic’ (Clarke, 1987) research subjects, especially but not only in the reproductive sciences (Bourne, 1973; Fridman, 2002; Goldsmith and Moor-Jankowski, 1972; Haraway, 1989; Schmidt, 1972). The infrastructures of basic science could be expanded to serve clinical medicine (Fridman, 2002; Goldsmith and Moor-Jankowski, 1972).

The 1930s was the decade of menstruation and cyclicity studies (Corner, 1951). Hartman (1939: 670) offered a highly explicit generalization about cyclicity across species in Endocrinology:

Those workers who have made first-hand observation on human material as well as that of monkeys feel, in general, that information gained from a study of sexual physiology in the higher monkeys is directly transferable to man. In the cyclic histological changes in the genital tract and in its response to hormonal stimulation no species differences of importance have been brought to light.

This article’s title names its intended audiences: ‘Studies on reproduction in the monkey and their bearing in gynecology and anthropology’. The clinical promise of the reproductive sciences was explicitly asserted (Hartman, 1939: 670):

Indeed, it is upon the results of experiments on the monkey that gynaecology has built up some sort of rationale for experimental work in the therapeutic control of menstrual disorders. More certain procedures looking towards further alleviation of sufferings peculiar to womankind awaits the continued cooperation of the gynaecologist and the student of primate anatomy and physiology.

Yet, despite Hartman’s initial claim of ‘direct transferability to man’, later in the article he qualifies this: ‘One gets the impression that monkeys are more unpredictable with reference to the onset of the menstrual flow than women, even though only the monkey data from the more favorable season of the year, September to April, are used’ (Hartman, 1939: 672). That is, even when deleting menstrual cycle data from monkeys for four or more months of each year, these embodied primates’ cyclic patterns clearly diverged from those of humans. Species differences were erased or de-emphasized. The social practices of transposition thus include ‘simplification work’ (Star, 1983). ⁶

Significantly, Hartman called for ‘cooperation’ between gynaecologists and primate anatomists and physiologists, in order to explicitly link clinical and basic research efforts. Such cooperative efforts had begun, Hartman noted, when Dr George Corner’s (1923) research on the menstrual cycle in rhesus monkeys stimulated a parallel study in human females by Dr Jessie King (1926). King’s exceptional work required women to provide self-reports on their menses and have regular vaginal smears. Subsequent cooperative research did not, however, involve women as active subjects (Clarke, 2004; Hanson, 2004).

The second exemplar of generalization important to the gynaecological/obstetrics market concerned embryonic pathology. In Corner’s (1981: 353–354) description of research on abnormal monkey embryos, the claim of generalizability is tacit rather than explicitly articulated – a common practice:

Bartelmez and I joined in a little monograph [1954] describing nine very early abnormal embryos of the rhesus monkey from the Carnegie colony. … [I]t is unique in the literature of primate embryology in that we could study, along with the embryos, the maternal ovaries and endometrium (lining of the uterus). The findings helped to lay to rest the old idea that embryonic pathology is always caused by uterine inflammation [a problem in the body of the mother]. In five of our cases the ovaries and endometrium were normal; the embryonic abnormality must have resulted from constitutional defects of the embryo itself. In other cases, the possibility existed that the abnormality of the embryo resulted from primary failure of the corpus luteum [in the mother’s body].

Here, as elsewhere, a reproductive scientist made a concrete research offering through generalization to obstetricians, gynaecologists and animal agriculturalists. The finding that serious pathology of the embryo/fetus could be found in a healthy mother was a radical departure from the canon. In humans, it was a first step in ‘absolving’ women from ‘blame’ for at least some proportion of fetal abnormalities and miscarriages. In animal agriculture, the utility of this generalization was that producing abnormal offspring might not condemn prized organisms as unfit for further reproduction. Transposition as a social process thus helped organize markets and resources as well as cement the reproductive sciences across their professional divides (Clarke, 1998: 157–162).

Through these and other research projects, reproductive scientists and others asserted the generality of findings from primates to humans to promote funding of expensive primate research colonies as a requisite infrastructure for biomedicine. They deemed the considerable expense of such colonies worthwhile because the research would ultimately be valuable for human health, precisely because of the greater transposability of findings from primates to humans.

Robert M. Yerkes, founder of the Yale Laboratories of Primate Biology, Inc., established at Orange Park, Florida, in 1929 (Yerkes, 1935), further argued for US-based colonies to regularize access to primates for research on the basis of international scientific competition (Clarke, 1987). In Almost Human, Yerkes (1925: 270) contrasted the relative absence of primate colonies for research in the US to the facilities available to Koehler in Germany, ‘Mrs Kohts’ in the new USSR, and researchers at the Pasteur Institute in French Guiana. Recent scholarship has confirmed the centrality of new forms of scientific institutionalization in the USSR – specifically the ‘monkey farm’ founded at Sukhumi in around 1926 (Fridman, 2002; Krementsov, 2008). In 1930, the Rockefeller Foundation began funding the Yale Laboratory of Primate Biology in Florida. By 1935, Yerkes’ (1935: 619) articulation of his research goals featured reproductive science: ‘the study of varied problems of primate reproduction, genetics, behavioral adaptation, hygiene and pathology’, precisely those areas most transposable to ‘man’.

The ramping up of research after the Second World War again provoked comparisons with research infrastructures in Soviet institutions, as part of the Cold War focus on scientific and technological competition. During the 1950s, many former imperial colonies in Africa and Asia became nation-states, and purchasing wild primates became challenging (Clarke, 1987; Goldsmith and Moor-Jankowski, 1972; Hanson, 2004). At the same time, intensive expansion of ‘postcolonial’ development plans, including goals of population control, fuelled the reproductive sciences and contraceptive research using primates (Greep et al., 1976). After visits in 1956 by American scientists to the well-established Soviet primate colony at Sukhumi, and the launching of Sputnik in 1957, the US network of National Primate Research Centers was funded by Congress in 1960, through the National Institutes of Health (Bourne, 1973: 487; Fridman, 2002). Primates from the new colonies were then used in polio research and drug testing (Goldsmith and Moor-Jankowski, 1972; Schmidt, 1972), and extensively in other research thereafter, including HIV/AIDS research. Thus, transposing primate bodies has been routinized in practice.

Producing dynamic relations

Given the structure of the modern life sciences, with the experiment as the major means of production of scientific knowledge by the First World War, assertions of species generality fit well with scientific research traditions, including scientists’ own cautionary warnings against ‘overdoing’ those assertions (for example, Ramsey, 1972). As exemplified here in the case of the reproductive sciences, such assertions drew human bodies into the scientific enterprise by association, legitimating the use of model organisms to multiple audiences with idealistic pronouncements about the ultimate human value of this work. Scientists thereby did not themselves need to work with living human materials, which would violate the clinical/basic research divide. Transposing findings developed with primates in basic science to humans in clinical medicine became key to selling reproductive science to biomedicine. It was important rhetorically as a new scientific technology, and financially in terms of garnering research funding (Clarke, 1998: 157–162, 207–230). Generalizability undergirded these links between different kinds of animals (including human) and the different social spaces such bodies inhabit, specifically labs and clinics.

Transposing techniques

Historically, assisted reproductive technologies have been developed in the highly capitalized arenas of agriculture and biomedicine, including artificial insemination, in vitro fertilization and embryo transfer (Biggers, 1984; Edwards and Steptoe, 1978; Herman, 1981). Public funding through the US Department of Agriculture, along with extensive capitalization of biomedical and agricultural technoscience, propels such technological developments (Fuglie et al., 2000). No such funding structures are as prevalent in animal conservation efforts. There is no National Institute for the Health of Wild Species (Wildt et al., 1993), an absence that many study participants would bemoan. Thus, the assisted reproduction of endangered animals was often described as a matter of transferring techniques used with domestic animals in agriculture to members of endangered species in zoos. Zoological parks in the US can thus be described as on the ‘receiving end’ of reproductive technology transfers – sites where technologies and aspects of the requisite infrastructures were imported rather than developed.

These efforts were initiated in the 1980s when some scientists in the zoological community became committed to refashioning assisted reproductive technologies to reproduce endangered and other zoo animals. Today there are on-going endeavours in using artificial insemination, in vitro fertilization and embryo transfer techniques – originally developed in the agricultural industry and refined in human infertility medicine – in research centres affiliated with zoological parks (Swanson, 2006; Wildt, 2004; Wildt et al., 2001). The use of nuclear transfer technology with animals of endangered species is thus an extension of such endeavours.

The following statements made by people involved in cloning endangered species show how they frame their interpretations of the social processes of transferring somatic cell nuclear transfer technologies into the domain of endangered species preservation.

Because there is a lot of funding for research with livestock from the USDA because we eat livestock, the research and the technologies used with these animals is much further ahead than what you have for endangered species. So I would say there is sort of a trickle down. It would look like a funnel. (Industry scientist, fieldnotes)

Each species has its own peculiarities of reproduction, and availability, and resources, and all those things so that each one has to be adapted. I pretty much spent my career adapting embryo transfer technology to the whole gamut of species. And that really is what is going on now with the nuclear transfer, is it’s being adapted to different species. (University scientist, interview)

These quotes highlight how a technique is developed with a particular species. Those species are themselves situated in certain social and historical processes that have coalesced into established and institutionalized human–animal relations, such as livestock improvement research usually pursued in schools of agriculture. The goal, then, is to transfer these techniques to other species located in other types of socially mediated spaces, in this case zoos.

It is important to emphasize that transferring a technique such as nuclear transfer, or any other assisted reproductive technology, requires considerable work (Clarke and Fujimura, 1992). For example, if a research centre decides to do somatic cell nuclear transfer, new equipment must be purchased; new laboratory protocols must be generated and tested; tasks must be redistributed; personnel must be trained in the micromanipulations involved in the processes; donor oocytes and somatic cells must be obtained, allocated and stored; surrogates must be procured and cared for, often for prolonged periods; and microscopes, cultures, and many other (often quite expensive) technologies and materials must be at hand. Most challenging of all, funding to afford all this must be generated. Such work is often effaced in discussions about technology transfer. But even this list of requisite humans, non-humans and tacit knowledges does not begin to elucidate the range of activities needed to make techniques work in different, highly localized settings. In concrete practice, for the nuclear transfer process to work, a whole slew of humans and non-humans must not only be brought together but also must learn how to relate to one another in particular ways. Cloning must be ‘articulated’ (Strauss, 1988) within a specific laboratory.

There are rewards, however. Transferring techniques allows both biotechnology companies and zoo scientists to make offerings to zoos in the form of the reproduction of rare species. Transferring techniques also offers zoos an identification with cutting-edge science, a core goal that has posed particular challenges for the modern zoological park. It further allows biotechnology companies to present themselves as altruistically contributing to endangered species preservation. Transferring techniques from agriculture and biotechnology to the zoo thereby allows some parts of different institutional identities to become transposable, all the while allowing each institution to retain its core means of identification.

Transposing bodies

Transferring techniques across species is a familiar concept aligned with the long-established animal model paradigm (Bynum, 1990). However, somatic cell nuclear transfer is not simply developed through research on domesticated species and then transferred to endangered species in a linear fashion, with clear demarcation between these categories. Rather, the bodies of domestic animals have also been incorporated into the actual experiments adapted for reproducing endangered wildlife using somatic cell nuclear transfer. Specifically, certain modifications have to be made to somatic cell nuclear transfer techniques when used with endangered wildlife, resulting in a revision and reorganization of this practice into what is now commonly referred to as ‘interspecies nuclear transfer’. Here, the nuclear DNA of an endangered animal is regenerated using an enucleated egg cell of a closely related, domestic species. This heteroplasmic embryo is then gestated by a domestic animal (Friese, 2010). Thus the bodies and body parts of animal models have literally been transferred into the very different places, spaces and bodies involved in endangered and zoo animal reproduction. The bodies of the model organisms are viewed as fungible enough with the targeted species that the two can be made interchangeable not only epistemologically but also materially. It is significant in this context that the model organism serves as a substitute rather than a site of comparison (Ankeny, 2007)

The decisions to clone a gaur and then a banteng must also be understood as attempts to work around two different kinds of inaccessible bodies and body parts simultaneously. Advanced Cell Technology was in the process of shifting its business and identity from a company producing transgenic animals for human therapeutics to one producing human stem cell therapies. The gaur project assisted in accomplishing this shift. Advanced Cell Technology wanted to discover whether it was possible to do nuclear transfer by using somatic cells from one species and ova from another one. This was an attempt to avoid using human oocytes that are difficult to acquire and allocate, and are politically contentious as well (Franklin, 2003; Maienschein, 2003). Advanced Cell Technology was interested in using domestic cow ova, plentiful materials that could be obtained from slaughterhouses, to produce embryos using human somatic cells to derive pluripotent stem cells. The idea was that by using cow ova, the resulting embryos would not count as human embryos, and the entire procedure could thereby be disentangled from political contestation (see also Franklin, 2003).

Significantly, the interchangeable nature of species bodies has been critical to both ‘reproductive cloning’ of endangered wildlife and ‘therapeutic cloning’ associated with human embryonic stem cell research. Here, domesticated animals are not only extensively studied with well-developed techniques supporting their reproduction; when used as models, their bodies are also transposed into new ‘experimental systems’ in order to simultaneously work around the inaccessibility of both human and endangered animal oocytes. This extends the logic of generality. If the bodies of animals from different species are treated as more or less the same in the epistemic cultures of biology and medicine, then the body parts of model organisms should be more or less interchangeable with those of targeted endangered species. This extension undergirds not only interspecies nuclear and embryo transfer, but also xenotransplantation.

Transposing infrastructures

The transfer of domesticated bodies in the practices of cloning endangered animals is enmeshed with the ‘infrastructuration’ (Edwards and Lee, 2006) of particular species as model organisms in the life sciences (Rader, 2004: 258, 260). Here, the increased use of a species in scientific research results in greater knowledge regarding that species, which has resulted in certain animals being both better models in and better commodities for the biosciences and biomedicine. Zoos lack this kind of infrastructure for doing reproductive science research involving endangered animals. While zoos have long defined themselves in part as scientific institutions, the utility of zoo animals as research objects has always been tenuous (Ritvo, 1996). Precisely because of the rarity of most zoo animals in general, and endangered species in particular, there has been little or no physiological research on them. This has meant that reproductive science research in zoological parks must address physiological questions that have long been answered with research on livestock, companion animals and humans. The following quote demonstrates this point:

One of the limitations with these captive animals of endangered species is we have such a lack of basic information about their basic biology. So whenever we’re starting with a new species, you have to figure out how long is the estrus cycle. Are they seasonal? What does a sperm sample look like? How do you synchronize them? So basic techniques, basic information that we very much take for granted with domestic animals, we know nothing about the biology of these endangered species so we have to go way, way back and start over at a very basic level. And then species differences are so great that when we learn enough about one species we try and then apply it to another species and quite often we have to – occasionally that might work but really with every different species we have to go all the way back to basics. So we’re always coming from so far behind is one of the limitations with these assisted reproductive techniques. (Interview, Zoo scientist, emphasis added)

Lack of animal subjects is coupled with a lack of knowledge regarding endangered animal physiologies, which means that zoos do not have the infrastructure generally required for developing assisted reproductive technologies.

Interspecies nuclear transfer was thus, in part, more feasible and hence more attractive to researchers working in zoological park settings because they could theoretically work around the lack of both endangered animals and knowledge about the physiologies of endangered species by utilizing well-studied, domestic animal bodies in the somatic cell nuclear transfer and embryo transfer processes. It is easier to work with a domestic animal than a wild or endangered species for other reasons as well, including their legal status as sacrifice-able and the relative safety for the researchers in physically interacting with most domestic as compared with wild animals. Thus researchers prefer to move the actual bodies of the animal models into experiments about endangered species when feasible. Well-studied organisms thus serve as infrastructure for developing reproductive technologies in the zoo.

In sum, interspecies nuclear transfer can be conceptualized as a potential means for overcoming the lack of actual endangered animals to work with and the corresponding lack of knowledge regarding the physiologies of endangered species. Rather than work with wild and endangered species, researchers actually do much of the work with domestic animals and domestic animal body parts. Hypothetically, one would not need to know very much about the reproductive physiology of the species that is being cloned because most of the work is done with well-understood domestic species. All that is needed from an endangered animal are preserved fibroblast cells. Here domestic animals do not simply provide models through which researchers can learn about reproductive physiology or tinker with reproductive techniques before working with rare and endangered animals. Rather, the domestic animals operate as an ‘infrastructure’ (Bowker and Star, 1999; Star and Ruhleder, 1996) comprised of available, well-studied bodies that legally and ethically can be deployed to know and reproduce animals of endangered species.

Disruptions of recalcitrant processes

As a practice, transposing the bodies and techniques of domestic and endangered animals emphasizes similarities across species. This is consistent with the development of animal models in the history of the 20th century biomedical sciences, which emphasized underlying physiological mechanisms that are conserved across species (Bolker, 2009; Bolker and Raff, 1997; Bynum, 1990; Logan, 2001, 2002; Löwy, 2000). Transposing the bodies and body parts of one species into the reproductive processes of another one extends this logic. If the basic physiological processes are the same or similar enough, then one species body can stand proxy for another. However, in practice, transferring bodies of members of domestic and endangered species involves recalcitrant processes of varying kinds, and biological, epistemological and socio-political issues are manifest.

First, efforts to generalize continue to face recalcitrant differences between species. For example, a zoo scientist told me of a project in interspecies embryo transfer where domestic cow eggs and surrogates were used to clone an anoa, an endangered bovine species. The scientist commented: ‘I predicted that this wouldn’t work because it’s a totally different line of bovine and it has a very different placentation. So I, I don’t think there’s any hope to do that.’ Indeed, managing differences between species is an important aspect of transposing different kinds of bodies in the process of both interspecies nuclear transfer and embryo transfer. For example, domestic cows and endangered cows often have different lengths of gestation, which need to be managed in interspecies embryo transfer. In addition, mitochondrial differences are often understood as key differences between species that may influence the viability of somatic cell nuclear transfer itself (Beyhan et al., 2007; Niemann et al., 2008; Rideout et al., 2001). Questions about the kinds of bodies and/or body parts that can or cannot (and should or should not) be made transferable, in what contexts and with what infrastructures, are all sites of lively debate in this situation, reinvigorating questions about species differences.

Second, some zoo scientists resist efforts to transfer techniques developed on domestic animals to endangered animal reproduction, because such efforts obscure significant differences between species. That is, some physiologists working in zoos are less interested in pursuing similarities between species than in exploring species difference per se and viewing zoo animals as ‘exemplary models’ (Bolker, 2009) for wildlife organisms.

It’s incredibly naïve for us to think that any of the technologies, or even some of the general knowledge, that have been developed for humans or livestock have much application at all to any of these wildlife species. If you think about it for a minute, it makes sense. Species are, by definition, different. And we have discovered over the many years that I’ve been doing this now – and I’ve been doing research with wildlife species since about 1978 – that all these species have these unique physiological characteristics. Those differences dictate whether or not a particular technique has any relevance. So the bottom line is that the technology – whether we’re talking about semen collection and sperm evaluation or we’re talking about cloning – the value is really as a tool to understand species uniqueness, the different mechanisms among species that make them so different from one another. (Interview, zoo scientist)

Transferring the bodies of domestic animals and the techniques developed with them in cloning experiments on endangered animals is clearly a matter of concern here. The restricted availability of endangered animals for cloning experiments poses an epistemological problem for these researchers.

‘Surrogate models’ (Bolker, 2009) continue to play a role in efforts to understand the physiology of wildlife from a perspective that emphasizes diversity as opposed to generality. A zoo scientist who focuses on endangered cats articulates this point:

As most of our cat studies go, a big chunk of the research was done on domestic cat models. You can do a lot of hypothesis testing with them under a lab situation, which is a lot more controlled. And you have relatively unlimited access to these animals. You can do a lot more experiments with domestic cats, [rather] than getting access to some of these wildcats in various [zoological] institutions. So the way we, in our program, address any big question is with the domestic cat [first]. Once we’ve thought that well, we’ve got some answers, then we go see if we can extrapolate those answers to other species. Sometimes it works out. Sometimes it does not. That’s where models do have limitations – in how it does apply to reproduction itself.

Significantly, this quote demonstrates that some zoo scientists do not view the physiology of well studied, domestic animals as generalizable a priori (Logan, 2002). Instead, like this zoo scientist, they examine both the similarities and differences between well-studied and lesser-understood species as explicit parts of the research programme.

Finally, transferring different kinds of animal bodies can create classificatory problems that have social and legal ramifications (Friese, 2010). For example, researchers from Advanced Cell Technology sacrificed three fetuses that developed from the gaur–cow heteroplasmic embryos, in order to assess their genetic origins and patterns of development (Lanza et al., 2000). This was considered normal and proper procedure among biomedical scientists who were used to working with animal models. However, after the scientists reported this practice in a scientific journal article, some conservationists argued that sacrificing the fetal animals violated the Endangered Species Act (ESA). The ESA states that no animal of an endangered species, nor any part of such an animal, should be harmed in any way. A scientist who had been involved in the project commented that had the gaur not been reclassified from endangered to threatened, the entire project would have been found in violation of the ESA. Transposing the bodies of different species thus brings different types of human-animal relations together, requiring careful negotiation of the biological, social and political embodiments in question.

Producing dynamic relations

Cloning and other reproductive technologies have been transferred to zoological parks and endangered species preservation sites, not only through the application of physiological knowledge from model organisms to other species but also through the application of the bodies of model organisms. This is part of an attempt to redistribute the reproduction of endangered wildlife across species boundaries.

However, biological differences between species at times ‘resist’ (Pickering, 1999 [1993]) such transfers. Different placentation, for example, is understood to resist the transfer of domestic cows into the reproduction of endangered anoa. Meanwhile, differences in the epigenetics of cellular development are understood as being recalcitrant to the transfer of domestic animal eggs into the regeneration of endangered animal cells (Chung et al., 2009). Thus the extent of generalizability is itself increasingly becoming a site of investigation within reproductive biology research programmes in US zoos.