7. VETERINARY AND HUSBANDRY

7.1. Captive Husbandry Requirements (John Brueggen)

Crocodilians are amazingly resilient animals, and have four basic requirements:

Fresh Water: Crocodilians in captivity should have enough clean, fresh water to completely submerge. This is necessary for both drinking as well as their psychological well-being. Even C. acutus and C. porosus, which have excellent salt glands, need fresh water, and choose to raise their hatchlings in or around fresh water until the young are about one year old. Crocodilians are masters of the interface between air and water, able to hide nearly their entire body beneath the water while still having ears, nose, and eyes above the water. Crocodilians usually feed and breed while in the water.

Dry Land: Crocodilians in captivity need to be able to completely remove themselves from the water. There needs to be enough dry land that the entire animal can haul out of the water and completely dry off, preferably in a sunny or heated location. Unlike amphibians, crocodilians do well to completely dry out. This is good for their skin, as algae and parasites are reduced during these drying periods.

Sunlight or Artificial Heat: Crocodilians are ectothermic vertebrates, dependent on their environment for their heat energy. While it is generally accepted that alligators are more cold tolerant than crocodiles, all crocodilians require sunlight (or a reasonable facsimile) to be active and digest their food. Captive crocodilians will need appropriate water temperatures and ambient air temperatures, but will also need a heat lamp or heat pad if direct sunlight is unavailable for basking. Social displays, growth, and digestion are reduced when optimum temperatures are not acquired, and temperature also plays a major role in sex determination of crocodilian embryos during egg incubation.

Food: Crocodilians are opportunistic, generalist feeders (G. gangeticus is the exception to this, consuming fish almost exclusively). In captivity, whole animal protein should be used. However, some pelleted diets have been formulated for captive crocodilians. Crocodilians may also consume non-traditional food items in captivity. In general, adults subsist quite well on one feeding per week, while hatchlings and juveniles may need to eat more often. Growth rates are directly tied to food intake of captive crocodilians. Most crocodilians feed in the water but lift their head out of the water to swallow, allowing gravity to pull the food down the throat. However, crocodilians are capable of swallowing their food underwater, despite popular beliefs to the contrary (Brueggen 2003).

It should be noted that the above is a very general summary of the basic needs of crocodilians in captivity. There are more complex issues, such as the space animals need (especially as the population increases), social behavior (even as it relates to parental care), enrichment, training, pheromones, nest building, egg incubation, and so much more. 

References 

Brueggen, J. (2003). Crocodilians swallowing prey underwater. Crocodile Specialist Group Newsletter 22(1): 22. 

Groves, J. (2007). A Guide To The Husbandry of Crocodilians. Chapter 5 in Crocodilian Biology and Captive Management Manual.

Vliet, K.A. (2001). Courtship behaviour of American alligators Alligator mississippiensis. Pp. 383-408 in Crocodilian Biology and Evolution, ed. by G.C. Grigg, F. Seebacher and C.E. Franklin. Surrey Beatty & Sons: Chipping Norton, Australia.   

Vliet, K.A. (1989). Social displays of the American Alligator Alligator mississippiensis. Amer. Zool. 29: 1019-1031. 

 

7.2. Zoological Collections (Kent Vliet)

Zoos, aquaria and other "living"; institutions are deeply involved in the conservation of endangered crocodilians. In recognition of the important roles that these institutions play in conservation, research and education, the CSG established a Zoos thematic group within its organizational structure. The group includes a few dozen members of the CSG experienced in captive management, zoo husbandry, captive breeding and reintroduction. Those seeking information or wishing to communicate with this group may contact the CSG Vice-chair of the Zoos group, Dr. Kent Vliet (kvliet@ufl.edu). 

Exhibition of captive crocodilians brings these animals and their conservation dilemmas into the public conscience. Zoo specimens serve as ambassadors for their species in the wild. Through visitation to zoos and aquaria, zoo education and outreach programs have the ability to reach millions of people worldwide each year. While the majority of these visitors live in urban areas and regions of the world outside the native range of crocodilians, zoo interpretation and education programs can raise the awareness of the importance of crocodilians in the natural world and encourage support and participation in programs necessary for the long-term survival and conservation of crocodiles. People must be inspired and motivated to care about and understand the threats that animals face in the wild. Thus, the actions of zoos can direct public participation and financial support to conservation projects of endangered and critically endangered crocodilians. Access to captive animals by scientists facilitates research and expands our knowledge of the biology and behavior of the group.

Although crocodilians have been held in captivity since at least ancient Roman times, historically, zoo collections were simply menageries of mixed species. It was only really in the late-1960s and 1970s when zoos first began keeping crocodilians in breeding pairs and captive reproduction was first recorded. Since that time, all living species of crocodilians have been reproduced under captive circumstances. Zoological collections in the USA include virtually all of the living crocodilian species, as do those in Europe. 

Conservation programs in zoos extend far beyond promoting the preservation of endangered species through ex-situ captive breeding programs. There is growing awareness of the important role ex-situ conservation plays in overall conservation strategies (Pritchard et al. 2011). And, with an increasing rate of global extinctions, continued habitat loss and the, as yet not fully understood, impact of global climate change, this role is certain to become more important in the future. 

Captive breeding populations in zoos may serve as assurance colonies or genetic reservoirs in case of an ultimate loss of the wild populations. There are relatively few, but highly significant, cases in which zoo animals have made enormous contributions to the initiation of recovery of critically depleted wild stocks. For instance, in the 1970s, an adult male Gharial (Gavialis gangeticus) from the Frankfurt Zoo, transported to India to assist an intensive captive breeding effort, became an important founder in the effort to head-start and reintroduce Gharial into wild sanctuaries. 

Managed, cooperative breeding programs in zoos are designed to maintain the genetic diversity of small, captive breeding populations. This attention to heredity proves invaluable when captive populations are needed as a source for reintroduction programs. The Chinese alligator (Alligator sinensis) Species Survival Plan (SSP) in Association of Zoos and Aquaria (AZA) zoos in North America has managed a cooperative breeding program for this species for almost three decades. The known genetic pedigree of these animals made them attractive to wildlife officials in southern China and Chinese alligators from the SSP were imported into China for a reintroduction effort on Chongming Island, near Shanghai. 

Within zoos, there is significant linking between in-situ and ex-situ conservation programs. The Cuban crocodile (Crocodylus rhombifer) faces the possibility of being genetically swamped in the wild due to hybridization with the sympatric populations of American crocodile (C. acutus). It is quite conceivable that no genetically pure C. rhombifer will remain in the wild in the next few decades. There has been a managed breeding program for the Cuban crocodile in AZA institutions in the USA for many years. European Association of Zoos and Aquaria (EAZA) institutions in Europe are initiating a similar program. These captive breeding programs, plus captive populations of genetically pure crocodiles in Cuba, may be the only long-term hope for continued existence of this beleaguered species. 

The CSG includes several taxon-specific conservation programs that bring experts from academic institutions, wildlife authorities, zoos and aquaria, and other related professions to focus their talents on conservation problems of critically endangered crocodilian species. The CSG Tomistoma Task Force has drawn great support of expertise from the zoo community in its efforts to protect the Tomistoma (Tomistoma schlegelii) and its habitats. The Chinese Alligator Fund initially grew from the efforts of zoo professional and private individuals interested in helping the plight of this species. The CSG has a Chinese Alligator Working Group which focuses its efforts on identifying potential release sites of captive-bred alligators and helping to establish new reintroduced populations.

The World Association of Zoos and Aquariums (WAZA) consists of more than 250 zoos and aquaria as institutional members, and has advanced several conservation strategies to implement conceptual development of practices and strategies for zoos and aquaria to adopt. Conservation Strategies are published in multiple languages to communicate the message of the strategies and to facilitate promotion and adoption to a broader audience. Through a series of workshops organized by WAZA in 2000/2001 a strategy was developed to increase WAZA participation in in-situ conservation. The strategy involves the branding of conservation projects or programs by WAZA, after these projects have met sets of endorsement criteria. Since this time, WAZA branding of projects has taken on increasing clout within the conservation community. Branding of conservation priorities in the Mesangat wetlands of East Kalimantan were instrumental in the establishment of the EAZA/IUCN SSC Southeast Asia Campaign mentioned below. The Mabuwaya Philippine Crocodile Conservation Program also has been WAZA-branded as proposed by Chris Banks (Melbourne Zoo). In partnership with the EAZA and the European section of the IUCN-SSC Conservation Breeding Specialist Group (CBSG), WAZA is establishing a World Zoo and Aquarium Conservation Database. This database currently catalogues more than 900 in-situ conservation projects supported by the international zoo community. 

AZA is a professional organization of more than 6000 institutions, individuals and vendors from all over the world. Since 1924, rigorous accreditation standards ensure the professional conduct and standards of AZA institutions and partner organizations. AZA-accredited institutions provide support for research and conservation projects worldwide. In 2010 alone, AZA facilities provided $US130 million in support to conservation projects in more than 100 countries. Species Survival Plans (SSP) for many of the world's most threatened and endangered species provide coordinated captive breeding programs, in-situ conservation programs, habitat preservation and restoration, public education and research. SSPs for crocodilian species are managed by the AZA Crocodilian Advisory Group (CAG), the first Taxon Advisory Group within the AZA. The CAG maintains studbooks and SSP programs for the most endangered crocodilians species (Alligator sinensis, Crocodylus rhombifer, C. siamensis, C. mindorensis, C. intermedius, C. (Mecistops) cataphractus, Gavialis gangeticus, Tomistoma schlegelii). 

ISIS, the International Species Information System, maintains an extensive database of animal species held in zoos and aquariums, and details of their zoo environments. This system, the Zoological Information Management Systems (ZIMS), links records from more than 800 member zoos and aquaria in at least 80 countries, and includes comprehensive data on more than 2.6 million captive animals of 10,000 species. 

EAZA is a professional association of zoos and aquariums in Europe, with more than 345 member institutions from 41 countries. The EAZA manages cooperative breeding programs. The Endangered Species Program (ESP), similar to the SSP programs of the AZA, has intensive, cooperative, population management plans for individual species. Each has a coordinator and a species committee, which make pairing, breeding and transfer recommendations designed to promote and maintain the genetic diversity of the captive population. RRPs include only specimens kept in EAZA institutions. There is an EEP for C. mindorensis and one was previously maintained for A. sinensis.

European studbook (ESB) programs are less intensive management plans than the EEPs. A studbook keeper maintains records of all specimens in the program and all life events, including data on births, deaths, transfers, etc. ESBs exist for C. rhombifer and T. schlegelii, plus Osteolaemus tetraspis is being considered. ESBs may include specimens from non-EAZA institutions and from some highly qualified private collections. The EAZA has a single Taxon Advisory Group for all reptiles. Fabian Schmidt (fschmidt@zoo-leipzig.de), Zoo Leipzig, oversees the crocodilian matters in this.  

The Southeast Asia Campaign, a joint venture between the EAZA and IUCN/SSC, raises public awareness and funds for the conservation of biodiversity in Southeast Asia. One project in this campaign, the Conservation of the Mesangat wetland in East Kalimantan, is of extreme importance to the conservation of two endangered species of crocodilians - T. shlegelii and C. siamensis. Both species occur in Mesangat Lake and the vast peat swamp forest surrounding it, an area salvaged from development from a local palm oil company and now proposed for permanent conservation by YASIWA - the Equatorial Conservation Foundation of Indonesia. 

International Zoo Educators Association (IZE) members dedicate themselves to improving the impact of conservation education programs in zoos and aquariums. 

The CBSG is a network of conservation professionals from around the world committed to developing scientifically-based, cooperative conservation programs aimed at saving threatened species. The CBSG has developed workshops aimed at gathering essential data for the scientific analysis of conservation strategies directed at endangered species. These Population and Habitat Viability Assessment (PHVA) workshops bring together attendees with a range of knowledge on biology, ecology, habitat, reproduction, genetics, GIS and land use patterns. Computer models use data compiled from these sources to evaluate the potential impact of various management strategies on the risk of population decline or extinction of the species. 

Other regional zoo associations exist, too numerous to list all:

* British & Irish Association of Zoos & Aquariums (BIAZA)

* Canadian Association of Zoos and Aquariums (CAZA)

* Mexican Association of Zoos & Aquariums (AZCARM)

* Pan African Association of Zoological Gardens, Aquaria & Botanical Gardens (PAAZAB)

* Sociadade de Zoologicos do Brasil (SZB)

* South Asian Zoo Association for Regional Cooperation (SAZARC)

* South East Asian Zoo Association (SEAZA)

* Zoo and Aquarium Association (ZAA)

References 

Acharjyo, L.N. (1999). Role of Nandan Kanan Zoological Park in the conservation of Indian crocodilians. ENVIS (Wildl. & Prot. Areas) 2: 1-4.

Arteaga, A., I. Cañizales, et al. (1996). Taller de analysis de la viabilidad poblacional y del habitat (PHVA) del Caiman Orinoco (Crocodylus intermedius). Conservation Breeding Specialist Group: Apple Valley, MN, USA.

Brazaitis, P. and Abene, J. (2008). A history of crocodilian science at the Bronx Zoo, Wildlife Conservation Society. Herpetol. Rev. 39(2): 135-148.

Conde, D.A., Flesness, N., Colchero, F., Jones, O.R. and Scheuerlein, A. (2011). An emerging role of zoos to conserve biodiversity. Science 331(6023): 1390-1391.

Fa, J.E., Funk, S.M. and O'Connell, D.M. (2011). Zoo Conservation Biology. Cambridge University Press: Cambridge, UK.

Honegger, R.E. and Zeigler, F.W. (1990). The 1989/1990 Crocodile surveys in European and American Zoos and Aquaria. Int. Zoo Yearb. 30: 153-157.

IUCN (2002). Technical Guidelines on the Management of Ex Situ Populations for Conservation. IUCN: Gland, Switzerland.

Lacy, R.C. (1993/1994). What is population (and habitat) viability analysis? Primate Conservation 14/15: 27-33.

Pritchard, D.J., Fa, J.E., Oldfield, S. and Harrop, S.R. (2012). Bring the captive closer to the wild: redefining the role of ex situ conservation. Oryx 46: 18-23.

Maunder, M. and Byers, O. (2005). The IUCN Technical Guidelines on the Management of Ex Situ Populations for Conservation: reflecting major changes in the application of ex-situ conservation. Oryx 39: 95-98.

Rao, R.J., D. Basu, et al. (1995). Population and Habitat Viability Assessment (PHVA) Workshop for Gharial. Report: 99 pp.

Seal, U.S. (1993). Population and Habitat Viability Assessment Reference Manual. IUCN-SSC Conservation Breeding Specialist Group: Apple Valley, MN, USA.

Soberon, R., Ross, P. and Seal, U. (eds.). (2000). Cocodrilo Cubano Análisis de la Viabilidad de la Poblacion y del Hábitat: Borrador del Informe. IUCN-SSC Conservation Breeding Specialist Group: Apple Valley, MN, USA.

WAZA (2005). Building a Future for Wildlife - The World Zoo and Aquarium Conservation Strategy. World Association of Zoos and Aquariums: Bern, Switzerland.

WAZA (2009). Turning the Tide: A Global Aquarium Strategy for Conservation and Sustainability. World Association of Zoos and Aquariums: Bern, Switzerland.

7.3. Health and disease diagnosis and management - Paolo Martelli & Brian Stacey

7.4 Humane killing guidelines Paulo Martelli

An "analysis on humane killing methods for reptiles in the skin trade"; was put together by a panel of experts, several of which from the ranks of the CSG.(document available online). The CSG vet group considered the conclusions and edited them to specifically suit crocodilians in Zoos and farms.

Hunting for sport or hunting and trapping by traditional hunters follow a different set of laws, regulations and traditional rules that are beyond the scope of this document.

The CSG Veterinary Group can be contacted for clarification or details of any of the below methods.

Acceptable Methods

Captive-bolt pistol (penetrating or non-penetrating)

This is the preferred method, alone or with a subsequent method to ensure death (pithing) if the brain is not immediately destroyed. See diagram of correct location to place bolt to maximize brain destruction (below). There are ongoing studies to develop crocodile stunners and in some countries regulations already in place.

Shooting

With appropriate caliber for size of the animal and in line with relevant legislation, training and safety protocols (effective, quick and humane). Minimizing the distance between the animal and the shooter will reduce margin for error for "missing"; the brain. See diagram of correct location to place shot for brain destruction (below). In some countries, regulations dictate that lead bullets must be retrieved and properly disposed of. If there is any doubt as to the accuracy of the shot, the crocodile should immediately be pithed.

Injection of overdose of pentobarbital

Contingent on the context and appropriate experience/training of the person (eg veterinarian, researchers). The meat must not be allowed to enter animal or human food chain. And carcass cannot be disposed in landfills. If there is any uncertainty as to death by injection (eg low body temperature affecting metabolism of drug or slow uptake of intraperitoneal/extravascular injection) subsequent pithing is recommended.

Pithing

Only after anesthesia or stunning (captive-bolt, blow or electrical stunning) or as a procedure following any other method to ensure complete brain destruction.

Discouraged Methods

Blow to the head with a hard implement

Must cause instantaneous destruction of the brain in combination with a subsequent method to ensure death (pithing) if the animal is only stunned. This technique is difficult to perform in crocodilians due to the thickness of the braincase and must be reserved only for situations where circumstances necessitate it.

Cervical transection

The CSG is aware that in many places animals are killed by cervical transection alone followed by exsanguination. The group is also aware that in many countries guns or electrical stunners are either illegal or not readily available. If cervical transection is used, it must be immediately followed by pithing. Also, all crocodile managers should aim to implement one of the recognized humane methods as soon as possible.

Unacceptable Methods:

Exsanguination, freezing, heating, suffocation, drowning, inhalation of toxic gases

Hunting for sport or hunting and trapping by traditional hunters follow a different set of laws, regulations and traditional rules and the above was not discussed to cover those particular instances.

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