The fact that South African Pedetes capensis has a hot pink fluorescent color under ultraviolet light was recently reported in Scientific Reports. Thanks to this, the rabbit, which has been nicknamed Disco Rabbit, is news that it is different from the known biofluorescent mammals.
The wavelength of light that the human eye can detect is approximately 400–700 nm, which we also call the visible range. Infrared or ultraviolet rays outside this area can only be seen through sensing tools. However, many animal species other than humans have eyes that can see various areas of light. It is usually interpreted as a result of evolution in a way that is more favorable for finding food or avoiding predators and finding mating partners, depending on the ecological environment in which the species are located. In mammals, it is known that the marsupial opossum (Didelphimorphia) and some rodents detect ultraviolet rays.
On the other hand, biofluorescence, in which living organisms fluoresce, is generally observed in invertebrates, fish, reptiles, and amphibians. In mammals, biofluorescence was observed in the genus Glacomys spp., the opossum (Didelphimorphia), and the platypus (Ornithorhynchus anatinus). They not only live in various ecological environments across three continents, but are also widely distributed in mammalian phylogeny, so they are interpreted to have evolved independently into biofluorescent properties. The function of biofluorescence has not yet been elucidated in detail, but it has been commonly thought that biofluorescent mammals are all nocturnal and have a connection with the dark environment.
The leap rabbit announced this time is also nocturnal. The researchers revealed that while studying biofluorescence through specimens of the New Continent Sky Squirrel and Anomaluromorpha at the Museum of Natural History in Chicago, they discovered that a rabbit that accidentally jumped also fluoresces. The 14 specimens of the museum were collected between 1905 and 1963 from various parts of Africa, including Angola, Botswana, Kenya and Tanzania, respectively. Four were males and ten were females. As a result of observing this specimen under several wavelengths from ultraviolet to visible light and analyzing it by fluorescence spectroscopy, these rabbits showed partial fluorescence in the abdomen and back of both females and males, but the absorbance was slightly different, the researchers reported. did.
The researchers also observed five more leap rabbits from Omaha's Henry Doorly Zoo and Aquarium to see if this was only observed in museum specimens, with the same results. They reported that their hair was wiped with dishwashing, but the fluorescence did not disappear or diminish.
Afterwards, the researchers extracted fluorescent substances from the rabbit's fur through chromatography. Here, fluorescent substances such as europorphyrin-I, europorphyrin-II, and heptacarboxylporphyrin were found. It was reported that some substances were not used as a standard reference substance for the analysis of fluorescent substances, but the detected names were unknown.
As a result of the analysis, the researchers concluded that through the objects of museums and zoos, these leap rabbits exhibit biofluorescence in both males and females, which is not caused by environmental factors or collection and storage processes, but appears to be due to substances naturally generated from the rabbit hair I concluded. Compared with other biofluorescent animal species, it is interesting to note that in addition to the porphyrin family, which is a substance that causes biofluorescence, other unidentified chemical components were found in leap rabbits.
It is not known why these leap rabbits glow. However, noting that jumping rabbits live independently from the herd, stay in burrows during the day and then search for food in the grass at night, the researchers hypothesized that this could be to protect themselves from predators.