Fundulus heteroclitus in the Laboratory: A History

The mummichog, Fundulus heteroclitus, was first used in thelaboratory as a source of ripe eggs and sperm to provide developingbony-fish eggs. These in turn were used mostly to study embryologicalprocesses and responses to various chemicals. Other investigationsat the end of the nineteenth and beginning of the twentiethcenturies dealt with regeneration, developmental genetics andhybridization, osmoregulation, behavior, and pigmentation, especiallycolor change. Except for experiments on chromatophore control,endocrinological studies did not get underway until the 1930s.They have included the functioning of the thyroid, adrenal,and pineal glands, and the endocrine control of reproduction,growth, osmoregulation, and calcium metabolism. Among more recentlystudied subjects are survival at subzero temperatures, adaptationto stress, weightless orientation in space, circadian rhythms,and the bioassay of the exophthalmos-producing substance ofman as well as other physiologically active factors. The singleattribute of the mummichog that has been most responsible forits remarkable popularity as a laboratory animal is its hardinessin captivity. Despite the fact that it is not widely availablelike the goldfish, is not easily bred in aquaria like the livebearingguppy, and has no value as a food or game fish like the trout,the mummichog has made a most substantial contribution to experimentalbiology