Architecture for Animals
The design of buildings to house animals presents architectural challenges of unusual complexity and originality, requiring the simultaneous satisfaction of the needs of the animals being housed, the desires of the human visitors who come to observe them, the requirements of the keepers who must manage them, and the aesthetic ambitions of the architects who design the enclosures. London Zoo, which has been building animal houses and enclosures for nearly two centuries, has addressed these challenges in a remarkable variety of ways, producing an architectural collection that ranges from modest Victorian brick structures to pioneering works of twentieth-century modernism. The zoo's architectural history is one of the most interesting and least-known chapters in the story of British architecture, and the buildings it has produced, at their best, are among the finest pieces of design produced in this country in any building type.
The earliest animal houses at London Zoo were designed by Decimus Burton, who also designed the lodge houses at Hyde Park Corner and various other significant London buildings of the 1820s and 1830s. Burton's zoo buildings, several of which survive in modified form, were conceived in a relatively conservative classicising style that reflected the architectural language of the period. The Giraffe House, the Clock Tower, and various other Burton structures established the basic planning principles of the zoo, with animal enclosures arranged along a network of paths and separated from each other by suitable landscaping. These early buildings were well suited to the zoo's original scientific purposes, providing clear views of the animals for scientific observation while maintaining the separation between the human and animal worlds that Victorian convention required.
The late Victorian and Edwardian periods brought a range of new building types to the zoo, reflecting both the expansion of its collections and the changing understanding of the appropriate architectural language for zoological institutions. The Reptile House of 1927, which remains one of the most architecturally distinguished Victorian-influenced buildings in the zoo, combined a traditional exterior with an innovative interior arrangement that sought to provide appropriate environments for reptiles from different climatic zones. The building's combination of technical sophistication and architectural confidence reflects the high point of the late Victorian and Edwardian zoological tradition, and its survival in largely original form makes it one of the most important buildings in the zoo's architectural collection.
The arrival of modernism at London Zoo in the 1930s was a revolutionary moment in the institution's architectural history and one of the most significant episodes in the wider history of British modernist architecture. The decision to commission Berthold Lubetkin and his Tecton partnership to design new buildings for the zoo reflected both the progressive instincts of the zoo's management and the growing influence of the European modernist movement in British architectural culture during the interwar period. Lubetkin, who had trained in Paris and had worked with Le Corbusier before establishing his own practice in London, brought to the zoo commission a depth of architectural culture and a structural inventiveness that transformed the possibilities for zoo architecture and that produced buildings of enduring importance in the wider history of twentieth-century design.
The formal and aesthetic qualities of the Tecton buildings at London Zoo reflect the fundamental principles of the modernist movement as Lubetkin understood them: the integration of structural innovation and aesthetic expression, the subordination of formal composition to functional requirement, and the use of new materials and construction techniques to achieve spatial effects that traditional building methods could not provide. But Lubetkin's modernism was never merely functional: it was always grounded in a powerful aesthetic sensibility that understood the zoo's buildings as works of art as well as works of engineering. The Penguin Pool in particular demonstrates this integration of the aesthetic and the functional at the highest level, producing a building that is simultaneously a piece of sculpture, a structural tour de force, and a carefully considered response to the specific behavioural requirements of its penguin inhabitants.
The Penguin Pool: A Masterpiece of Modernism
The Penguin Pool, designed by Lubetkin and Tecton and completed in 1934, is one of the most celebrated pieces of modernist architecture in Britain and one of the most photographed structures in London Zoo. The pool's famous interlocking spiral ramps, which allow penguins to ascend from the water level to a raised platform and descend again by a different route, are constructed in a reinforced concrete of exceptional thinness that exploits the structural potential of the material with extraordinary confidence and skill. The ramps, which appear almost impossibly thin and delicate for their span, are the product of calculations by the structural engineer Ove Arup, one of the founders of the engineering firm that still bears his name and that has been responsible for some of the most structurally innovative buildings in the world. The collaboration between Lubetkin and Arup on the Penguin Pool was one of the most productive architect-engineer collaborations in British architectural history.
The geometry of the Penguin Pool is based on the intersection of two ellipses at different angles, a formal idea that generates the complex curves of the ramps and the containing wall and gives the whole composition its characteristic quality of fluid, dynamic movement frozen in concrete. This geometry was derived from careful analysis of the penguin's natural behaviour, particularly its characteristic waddling gait on land and its extraordinary agility in the water, and was intended to create an environment that would display these behavioural qualities to maximum advantage for the observing visitor. The relationship between the formal geometry of the pool and the functional requirements that generated it is one of the most interesting aspects of the building's design and illustrates Lubetkin's ability to transform functional analysis into formal beauty.
The structural achievement of the Penguin Pool ramps is extraordinary by any standard. The outer ramp, which spans approximately fifteen metres at its widest point, is supported by a relatively simple system of columns and beams, but the inner ramp, which appears to float unsupported at the end of its spiral, is actually held up by the outer ramp through a complex system of internal reinforcement that transfers the loads from the free end of the inner ramp back to the structure of the outer ramp and from there to the foundations. This structural solution, which required Arup's calculation of forces that had not previously been considered in a building context, demonstrates the sophisticated engineering thinking that underpinned Lubetkin's apparently effortless formal experimentation.
The debate about the future of the Penguin Pool, which emerged when it became clear that the concrete ramp surfaces were causing foot problems for the penguins who used it, raised fundamental questions about the relationship between architectural heritage and institutional function that have been widely discussed in both the architectural and conservation communities. The decision to remove the penguins from the pool and to adapt it for other uses was the right one from the perspective of animal welfare, but it involved the loss of the specific functional purpose for which the building was designed. An architecture that was conceived as the perfect integration of form and function has been reduced, by the evolution of scientific understanding, to a form from which the function has been removed. The building retains its extraordinary formal quality, but it no longer fulfils the purpose that generated that formal quality, and this disjunction raises questions about the nature of architectural value that do not admit of easy answers.
The conservation of the Penguin Pool as a listed building of Grade I importance reflects the consensus view of the architectural community that the building's significance goes well beyond its original functional context and that it merits preservation as a work of art of the highest order regardless of its current use. The pool is one of the most important British examples of early modernist architecture, a building that demonstrated at a specific historical moment what the new movement was capable of achieving when given a sympathetic client and the freedom to experiment. Its preservation is thus an act of cultural conservation as well as an act of architectural conservation, maintaining for future generations the evidence of a specific moment in the history of architectural thought.
The Gorilla House and Other Tecton Works
The Gorilla House, also designed by Lubetkin and Tecton and opened in 1933, predates the Penguin Pool by a year and represents the firm's first major work at the zoo. The building's circular plan, with a central rotating mechanism that allows the gorilla enclosure to move from the indoor to the outdoor sections of the building, was a response to the specific behavioural and climatic requirements of these large primates, who need access to an outdoor environment but who must also be able to retreat to a heated indoor space when London's weather makes outdoor life impractical. The rotating mechanism, which was Tecton's response to the problem of providing controlled access between indoor and outdoor spaces without creating an escape risk, was a genuinely original piece of engineering thinking and illustrates the firm's commitment to solving functional problems through technical innovation rather than conventional architectural solutions.
The formal character of the Gorilla House is quite different from that of the Penguin Pool, reflecting the different functional requirements of the two buildings and the different stage in Lubetkin's and Tecton's development that each represents. The Gorilla House has a more conventionally modernist character, with its clean white walls, horizontal windows, and flat roof reflecting the influence of the Bauhaus and the International Style that dominated European modernism in the early 1930s. The building is significant as one of the first genuinely modernist structures to be built in London, and its reception at the time of its opening was a landmark in the gradual acceptance of modernist architecture in Britain.
The several other Tecton buildings at London Zoo, including the North Gate kiosks and various ancillary structures, demonstrate the firm's ability to work at different scales and in different formal registers while maintaining a consistent quality of spatial thinking and material handling. These smaller structures, which might easily be overlooked in favour of the more celebrated Penguin Pool and Gorilla House, are in their own way equally impressive, showing the same attention to detail, the same responsiveness to functional requirements, and the same quality of workmanship that characterise the major works. Taken together, the Tecton buildings at London Zoo form one of the most important collections of early British modernist architecture in existence, and their preservation and maintenance is a priority for both the zoo and the wider architectural conservation community.
The influence of the Tecton buildings at London Zoo on the subsequent development of British modernist architecture has been very considerable. The buildings demonstrated, at a time when modernism was still struggling for acceptance in Britain, that the new architecture was capable of the highest quality of design and that it could engage successfully with the most challenging functional requirements. The Penguin Pool in particular became an emblem of the modernist movement's possibilities, reproduced in architectural publications, discussed in schools of architecture, and celebrated by critics and architects as a demonstration of what the integration of structural innovation and aesthetic ambition could achieve. The building's influence on subsequent generations of British architects, who grew up with the Penguin Pool as one of the canonical examples of what architecture could be, is incalculable.
The Snowdon Aviary
The Snowdon Aviary, designed by Lord Snowdon (Antony Armstrong-Jones), Cedric Price, and the structural engineer Frank Newby, and opened in 1965, represents a very different moment in the architectural history of London Zoo. Where the Tecton buildings of the 1930s drew on the continental modernist tradition to produce buildings of formal elegance and structural refinement, the Snowdon Aviary belongs to a very different tradition: the British engineering culture of the 1960s, with its emphasis on technical innovation, flexibility, and the honest expression of structural forces. The aviary's vast tent of steel cables and nylon mesh, supported from a series of asymmetric steel masts, is a structural tour de force that opened new possibilities for large-span, lightweight structures and demonstrated the creative potential of tensile construction at a scale that had not previously been attempted.
The spatial experience of the Snowdon Aviary is one of the most remarkable in London Zoo. Entering through the airlocked double doors at the base of one of the masts, the visitor finds themselves in an enormous volume of enclosed space that seems to defy the conventional categories of indoor and outdoor. The mesh structure allows light and air to pass freely through, so that the interior feels almost open while being in reality a controlled environment capable of housing large numbers of freely flying birds. The birds themselves, which include various species of large exotic birds that use the full height of the enclosure for their flight, complete the extraordinary spatial experience by demonstrating the full potential of the space for natural avian behaviour. The aviary is, from the visitor's perspective, one of the most exciting spaces in London Zoo and one of the most memorable spatial experiences in any building in London.
Cedric Price's contribution to the Snowdon Aviary design is an interesting one, reflecting his characteristic interest in flexible, adaptable structures that could evolve with changing needs and that resisted the conventional architecture's tendency to fix programmes and relationships permanently in built form. Price's involvement with the aviary reflects the wider engagement with zoo design that he pursued through various speculative projects in the 1960s and 1970s, in which he explored the idea of zoo architecture as a form of environmental design that could shape animal behaviour while remaining responsive to the animals' changing needs. While the Snowdon Aviary is a more conventional building than Price's most radical proposals, it reflects his thinking about the relationship between structure, space, and the specific requirements of its non-human occupants.
The structural engineering of the Snowdon Aviary by Frank Newby is a landmark in the development of British structural engineering practice. Newby had worked with Frei Otto, the German architect and structural engineer who was the primary pioneer of tensile structural systems, and brought to the aviary commission a deep understanding of the principles and possibilities of cable-net structures. The calculation of the forces involved in a structure of this scale and complexity, at a period before computer-aided structural analysis was available, required both theoretical sophistication and practical ingenuity, and the success of the resulting structure, which has performed without significant structural problems for over fifty years, is a testament to the quality of Newby's engineering thinking.
The Zoo's Contemporary Architecture
The contemporary architecture of London Zoo, which has been shaped by the changing understanding of animal welfare and the growing emphasis on conservation that has transformed zoological practice since the late twentieth century, represents a very different approach from both the modernist masterpieces of the Tecton period and the engineering bravado of the Snowdon Aviary. The new animal habitats that have been created in recent decades at the zoo, including the Gorilla Kingdom, the Tiger Territory, and the In with the Lemurs enclosure, reflect the contemporary emphasis on providing animals with environments that support their physical and psychological wellbeing and that illustrate, for the visiting public, the threatened status of the species being housed.
The architectural language of these new facilities is generally more naturalistic than the earlier modernist buildings, seeking to create the illusion of natural habitat within the zoo setting rather than celebrating the artificiality of the architectural intervention. The Gorilla Kingdom, which replaced the original Lubetkin Gorilla House, creates an environment of tropical forest vegetation, water features, and climbing structures within a large enclosure that seeks to provide the gorillas with a range of behavioural opportunities approximating those of their natural habitat. The success of this approach in improving the welfare of the zoo's gorilla population has been documented by the zoo's own scientific staff and represents a genuine advance in the application of behavioural science to zoo design.
The challenge of creating high-quality contemporary architecture within the context of a zoo that contains listed buildings of considerable historical significance is one that the zoo and its architects must address in every new building project. The proximity of the Penguin Pool, the Gorilla House, and the Snowdon Aviary to any proposed new structure creates both constraints and opportunities for architectural dialogue, and the quality of contemporary zoo design is partly a function of the skill with which new buildings relate to these exceptional predecessors. The best of the recent buildings at London Zoo show an awareness of this context and seek to engage with the zoo's architectural history in positive and creative ways, while the less successful ones simply ignore the historical context in favour of a generic naturalistic aesthetic that could be applied to any zoo in the world.
*Published in the Hampstead Renovations Heritage Collection — exploring the architecture, history, and stories of London’s most remarkable neighbourhoods.*