5 Dollars - Elizabeth II Heaviside's dolphins

Oliver Heaviside's dolphin (Cephalorhynchus heavisidii) is named not for the Victorian mathematician Oliver Heaviside, as is commonly assumed, but for a Captain Haviside who transported early specimens to the Natural History Museum in London — the taxonomic name was simply misspelled and stuck. Cook Islands issued a broad run of wildlife conservation crowns throughout the early 1990s, farming the series largely for the collector market rather than circulation, with this piece among dozens struck to the same specifications under that program.