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One of the earliest studies of crocodilian genetics was conductedat the Bronx Zoo by human geneticist Maimon Cohen, director ofthe Cytogenetics Laboratory of the Greater Baltimore MedicalCenter, and herpetologist Carl Gans (Cohen and Gans 1970). Withthe advent of molecular genetics technology, a new generation ofscientists emerged to give us a fresh look at the relationships amongcrocodilian species: George Amato, first at the Zoo and now at theAmerican Museum of Natural History (Amato 1991, 1994; Amatoet al. 1998); paleontologist Chris Brochu of the University of Iowa(Brochu 2001; Brochu and Densmore 2001), and Lew Densmoreof Texas Tech University (Densmore 1983; Densmore andDessauer 1984; Densmore and Owen 1989; Densmore and White1991).Roland A. Coulson and Thomas Hernandez (Coulson andHernandez 1964, 1983), of Louisiana State University, pioneeredwork on crocodilian metabolism working with Ted Joanen and hiscolleagues at Rockefeller Refuge.The Right Time and the Right Place for CrocodiliansThe United Nations Convention on International Trade in EndangeredSpecies of Wild Fauna Flora (CITES) came into beingin 1973 and called attention to the alarming depletion of crocodiliansworldwide. The Lacey Act of 1900 was broadened and theBlack Bass Act of 1926 and the Endangered Species Act (ESA)(1966) were combined and amended, which gave sweeping protectionsto crocodilian species throughout the world. The exoticreptile leather trade was itself facing extinction as wild populationsplummeted and anticipated profits evaporated, because thedemands on the resource outstripped the legal and illegal supplyof raw skins. In the United States, the American Alligator, the symbolof America’s southland, was endangered. The Wildlife ConservationSociety (then the New York Zoological Society) and thereptile department were at the heart of the crocodilian conservationmovement. F. Wayne King (1967–1973) had succeededDowling as Curator of Reptiles and he soon developed a consuminginterest in crocodilian conservation, expanding on the crocodilianwork begun by Dowling and Brazaitis (1966). King organizeda meeting in 1971 between law enforcement agencies, Louisianaand Florida wildlife authorities concerned with the plight ofAmerican alligators, and representatives of the exotic leather trade.The first comprehensive work on species identification of crocodilianhides and products was introduced to facilitate wildlife lawenforcement (King and Brazaitis 1971) followed by the speciesidentification of living crocodilians (Brazaitis 1973a). These factorsprovided a huge incentive to develop captive breeding programs.In this new era at the Zoo, we still had no accommodations forbreeding crocodilians, no conviction that crocodilians could besuccessfully bred in artificial pools, and no official plan to initiatea crocodilian breeding program at the Bronx Zoo. Then, one dayin March 1964, a maintenance truck parked behind the ReptileHouse as the workers enjoyed a coffee break. In the back of thetruck was a discarded wooden tub that had served for many yearsas a temporary pool for a Pigmy Hippopotamus in the ElephantHouse. It measured about 2.5 m in length, 2 m in width, and 70 cmdeep at its deepest end. The reptile house keepers commandeeredthe half-rotted tub, installed it in the conservatory behind the westpools, and immediately populated it with a trio of Chinese Alligators(Figs. 9, 10). The first Bronx Zoo endangered crocodilian speciesbreeding initiative was born (Brazaitis 1968). Something wasmissing, however, and no breeding occurred.The west crocodilian pools and the conservatory areas (Fig. 11)were eventually retrofitted in 1981 to include two off-exhibit breedingpools, five nesting areas, and three main exhibit breeding pools.Conspicuous is the exceptionally small size of the complex andits nesting areas, and, in particular, the shallow nature of the pools.The main exhibit breeding pools (1, 2, 3) are less than 65 cm attheir deepest point (Table 2).A number of endangered species in the collection had nowreached sexual maturity, and with improved diets and health, beganto display reproductive behavior. Because more than one species,following their own intrinsic breeding cycles, would be breedingwithin a relatively short time period, it was necessary to establisha “breeding calendar,” to anticipate having the appropriateaccommodations ready at the right time for the right animals. Thecalendar indicated what species was anticipated to be breedingduring what period, and when the females were scheduled to layeggs. “Musical crocodiles” became the theme, as males and femalesof one species after another were scheduled in rotation, firstto pair and breed in the main or rear breeding pools. Then, femaleswere isolated in secluded rear pools during gestation andlater given access to a nesting enclosure to deposit their eggs. Finally,the female crocodile was rotated out to make room for thenext gravid female. Eggs would be removed immediately afterlaying for artificial incubation in the reptile nursery. Hatchlingsand growing young, up to a meter in length, were then reared ingalvanized cattle troughs on the second floor of the Reptile House,at about 30–35°C, under black light and color-corrected daylightfluorescent lights. In 1983, eggs of three species of crocodilianswere under incubation simultaneously.To date (2008), 10 species of crocodilians have been successfullybred at the Bronx Zoo. Prior to 1980, unanticipated and unrecordedreproduction had taken place with the hatching of singleeggs of West African Dwarf Crocodile, Osteolaemus tetraspis, anda Smooth-fronted Caiman, Paleosuchus trigonatus, found in thepool water. Behler et al. (1987) provided an overview of crocodilianreproduction at the Bronx Zoo.A Chronology of Crocodilian ReproductionInitially, the species we bred were the species that were alreadyon hand. As husbandry techniques were refined and new data onthe status of wild populations emerged, captive breeding programsfocused and gave priority to the most critically endangered species.Programs evolved to include collaborative efforts amongconsortiums of interested private individuals, zoological institutions,and governments; the Crocodilian Advisory Group of theAmerican Zoo and Aquarium Association, and the IUCN CrocodileSpecialist Group. Dedicated space and resources are limited,and priorities changed as some species and wild populations recovered.Yacare Caiman, Caiman yacareThe Yacare Caiman of the grasslands of central South Americadeserved special interest. Decimated by excessive hide hunting, it142 Herpetological Review 39(2), 2008