Zebrafish their larval stages. In 2011, the British Heart Foundation ran an advertising campaign publicising its intention to study the applicability of this ability to humans, stating that it aimed to raise £50 million in research funding. Zebrafish have also been found to regenerate photoreceptor cells and retinal neurons following injury, which has been shown to be mediated by the dedifferentiation and proliferation of Müller glia. Researchers frequently amputate the dorsal and ventral tail fins and analyze their regrowth to test for mutations. It has been found that histone demethylation occurs at the site of the amputation, switching the zebrafish's cells
Red-legged kittiwake differ from the adults, lacking the black tail band and 'W' across the wings of juvenile black-legged kittiwakes. Juveniles take three years to reach maturity. Adults are long, with an wingspan and a body mass of . Like the Pacific race of black-legged kittiwake, the red-legged kittiwake has a well-developed hind toe. As occasional individual black-legged kittiwakes have reddish legs, any reports of red-legged away from the subarctic Pacific must record all of the other differences, not just the leg colour, for acceptance by bird recording authorities. The red-legged kittiwake feeds on fish such as lanternfish (Myctophidae), squid and invertebrates.