Although most research is done on rats and mice, some human biological and psychological characteristics are most closely resembled in other animals.
PIGS have been instrumental in studying the healing process of burn victims. Pig skin serves as a temporary bandage that protects patients from infection and allows human skin to gereate.1
- One of the greatest contributions of pig research has been the development of the CAT scan, which allows doctors to examine organs without surgery.2
- Like dogs, pigs are used for studies of heart surgery and anaesthesia and nonsurgical treatments for heart-attack patients.
Research on SHEEP with kidney failure allowed surgeons to perfect and implant the arteriovenous shunt, a device that allows patents with kidney failure to be connected to dialysis machines for long-term treatment.
Research on sheep also has led to an understanding and treatment of problems that occur during human pregnancies and in infants soon after birth. For example, sheep have been used in the development and testing of a device that assists lung function in infants soon after birth.3
FERRETS have been used in studies of the influenza viruses and other viral diseases.4
WOODCHUCKS have brought insight into the cause of human liver cancer. Woodchucks and humans have similar hepatitis viruses. Researchers have found a correlation between the hepatitis B virus and the development of liver cancer, a condition found in both humans and woodchucks.5
The ARMADILLO is the only animal besides primates and mice in which the leprosy bacillus grows. Scientists are able to test a vaccine for people already suffering from the disease and are working to develop a preventative treatment in areas of the world where leprosy is most prevalent.6
GUINEA PIGS are used in a variety of studies. Their historical importance is shown by “guinea pig” being synonymous with “research subject.”
- Guinea pigs are used in nutritional studies.
- Guinea pigs need vitamin C provided in their diet, making it easy for a deficiency to be induced and studied.7
LOBSTERS are being used to study motor coordination to treat diseases such as syphilis, Parkinson’s disease and Huntington’s chorea. Whereas humans have 10-100 trillion neurons, lobsters have only 30. This small number allows researchers to pinpoint and study the electrical and chemical exchanges in the nervous system that go into the process of walking.8
Because they have anatomically similar, although larger, middle ears as humans, CHINCHILLAS are good models for treating childhood middle-ear infections.9 Chinchillas also have been used to study hearing loss resulting from exposure to loud noises.
ELECTRIC EELS are used in neurobiological studies, and the information is applied to the human nervous system. The Amazonian electric eel delivers shocks to its enemies and prey, making it an important model for the study of bioelectrical and chemical spheres of the nervous system.10
Because the offspring of OPOSSUMS develop in a pouch outside the body, scientists use these marsupials to study early organ and system development such as the central nervous system and the immune system.11
- Opossums also are used to study the oesophagus, since its physiology is similar to that of humans.12
- In captivity, opossums develop bacterial endocarditis so they can be a model for the study of the disease.13
ANGLERFISH are studies for their islets of Langerhans, which produce insulin and other hormones. Researchers are finding how insulin is produced and applying this information to diabetes treatment in humans.14
The heart tissue of the AXOLOTL, or Mexican salamander has been used by researcher to manipulate heart cells to divide in a dish. By doing this, scientists are trying to determine how heart-cell division is possible and apply the information to the human heart, which does not regenerate cells after a heart attack.15
SLUGS have played an instrumental role in research concerning human short- and long-term memory and character-growth processes. Although slugs are simple creatures, they have the human-like capacity to act based on past painful and pleasurable experiences.16
Scientists use PIGEONS to study coronary heart disease. When certain species of pigeons are fed a high-cholesterol diet, they develop atherosclerosis, or hardening and thickening of the arteries. This makes pigeons good models on which to test possible treatment for the disease in humans.17
There are many species of FISH used in biomedical research including studies of temperature and electrolyte regulation, genetics, bacterial diseases and water pollution.
- Goldfish are used in neurological and vision studies.
- Rainbow trout are used as models for studying liver cancer.
- The immune system of sharks appears to make them virtually invulnerable to cancer. Scientists are investigating the immune cells of sharks to determine whether they are more efficient than those of humans.
- Tropical fish are used in studies of skin tumours, or melanomas.18
ENDANGERED ANIMALS taken from the wild are not used for research, but a great amount of research is being conducted toward their preservation, mostly in the area of reproduction, including embryo transfer to assist in their survival.
1Nanney, LB: Epidermal and dermal effects of epidermal growth factor suring wound repair. J Invest Dermatol 1990 May; 94(5):624-9.
2 National Research Council: Use of Laboratory Animals in Biomedical Research. Washington, D.C.: National Academy Press, 1989.
3Kinsella, JP; Gerstmann, DR; Rosenberg, AA: the effect of extracorporeal membrane oxygenation on coronary perfusion and regional bloodflow distribution. Pediatr Res 1992 Jan; 31(1):80-4.
4 Rarey, KE; Davis, JA; Rush, NL; Deshmukh, DR: Effects of influenza infection aspirin, and an arginine-deficient diet on the inner ear in Reye’s syndrome. Annotol Rhinal Laryngol 1984 Nov-Dec; 93(6Pt 1):551-7.
5 Popper, H; Roth, L; Purcell RH; Tennant BC; Gerin JL: Hepatocarcinogenicity of the woodchuck hepatitis virus. Proc Natl Acad Sci USA Feb; 84(3):866-70.
6 Truman, RW; Shannon, EJ; Hagstad, HV; Hugh-Jones, ME and others: Evaluation of the origin of Mycobacterium leprae infections in the wild armadillo, Dasypus novemcinctus. Am J Trop Med Hyg 1986 May; 35(3); 588-93.
7 Navia, JM and Hunt, CE: Nutrition, Nutritional Diseases and Nutrition Research Applications. In: Wagner, JE and Manning, PJ (eds.), The Biology of the Guinea Pig, Academic Press, NY, 1976.
8 Dickinson, PS; Mecsas, C; Marder, E: Neuropeptide fusion of two motor-pattern generator circuits. Nature 1990 Mar 8:344(6262):155-8).
9 Reilly, JS; Doyle, WJ; Cantekin, EI; Supance, JS and others: Treatment of ampicillin-resistant acute otitis media in the chinchilla. Arch Otolaryngol 1983 Au; 109(8):533-5.
10 Powers, D: Fish as Model systems. Science 246 (Oct. 20, 1989): pp 352-358.
11 Cutts, JH; et al: General Observations on the Growth and Development of the Young Pouch opossum, Didelphis virginiana. Bio. Neonate, 33:264-272, 1978.
12 Sarna, SK et al: Myogenic and neural control systems for esophageal motility. Gastroenterology, 73(6):1345-1352, 1977.
13 Sherwood, BF et al: Experimental bacterial endocartitis in the the opossum (D. Virgininan). III. Comparison of spontaneous occurring endocarditis with that induced experimentally by pyogenic bacteria and fungi. Amer. J. Path., 64:513-520, 1971.
14 Milgram, SL; McDonald, JK; Noe, BD: Neuronal influence on hormone release fro anglerfish islet cells. Am J Physiol 1991 Oct;261(4 Pt 1):E444-56.
15 McCourt, R: Model Patients. Discover. August 1990: 36-41.
16 Montgomery, G: Molecules of Memory. Discover13 (Winter 1990-91); 38-47.
17 Clarkson, TB; Prichard, RW; Loftland, HB and Goodman, HO: the pigeon as a laboratory animal. Lab Animal Care 13(6): 767-780, 1963.
18 Klontz, GW: Fish as Research Models. Animal Models for Biomedical Research IV. National Academy of Science, Wahsington, D.C., 1971.