Animals are used in behavioural and biological research in special and significant ways. Many medical advancements that improve human life are based on laboratory animal research studies. Scientists carefully and thoughtfully select and justify the specific animal models used in their research, adhering to current legal requirements, the principles of the 3 R´s (reduction, reuse, and refinement), and ensuring that animals are used only when no other research solution is feasible or available. The laboratory animals most often used in biomedical research so far have been rodents (mice, rats, and guinea pigs), but in the current development of research, researchers have turned their attention to alternatives such as zebra fish and the Xenopus (clawed frog), although anatomically and physiologically different from humans, following the sequencing of their genomes, it was demonstrated that the main genes involved in certain pathologies in humans are similar to those in these animal models.