DOCUMENTARY LION BATTLE ZONE FULL DOCUMENTARY WILDLIFE ANIMALS 2013 HD EN ESPA?OL

In the U.S., the numbers of rats and mice used is estimated to be between 20 and 100 million a year.[75] Other rodents commonly used are guinea pigs, hamsters, and gerbils. Mice are the most commonly used vertebrate species because of their size, low cost, ease of handling, and fast reproduction rate.[88][89] Mice are widely considered to be the best model of inherited human disease and share 99% of their genes with humans.[88] With the advent of genetic engineering technology, genetically modified mice can be generated to order and can provide models for a range of human diseases.[88] Rats are also widely used for physiology, toxicology and cancer research, but genetic manipulation is much harder in rats than in mice, which limits the use of these rodents in basic science.[90] Nearly 200,000 fish and 20,000 amphibians were used in the UK in 2004.[91] The main species used is the zebrafish, Danio rerio, which are translucent during their embryonic stage, and the African clawed frog, Xenopus laevis. Over 20,000 rabbits were used for animal testing in the UK in 2004.[91] Albino rabbits are used in eye irritancy tests (Draize test) because rabbits have less tear flow than other animals, and the lack of eye pigment in albinos make the effects easier to visualize.[91] Rabbits are also frequently used for the production of polyclonal antibodies. 

 Cats 

 Cats are most commonly used in neurological research. 24,221 cats were used in the U.S. in 2013,[92] around half of whom were used in experiments which have the potential to cause “pain and/or distress”[93] though only 0.3% of cat experiments involved potential pain which was not relieved by anesthetics/analgesics. 

 Dogs 

See also: Laika and Soviet space dogs Dogs are widely used in biomedical research, testing, and education—particularly beagles, because they are gentle and easy to handle, and to allow for comparisons with historical data from beagles (a Reduction technique). They are used as models for human and veterinary diseases in cardiology, endocrinology, and bone and joint studies, research that tends to be highly invasive, according to the Humane Society of the United States.[94] The most common use of dogs is in the safety assessment of new medicines [95] for human or veterinary use as a second species following testing in rodents, in accordance with the regulations set out in the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. The U.S. Department of Agriculture’s Animal Welfare Report shows that 67,772 dogs were used in USDA-registered facilities in 2013.[96]