Category: Biology

Exploring the Luminescent Life of Fireflies | July 05 2025, 05:02

While walking with Yuka, suddenly the owner falls on his knees and digs around in the grass for a while. That’s when I found a firefly and wanted to capture it lighting up. The firefly Photinus pyralis is quite common here, but I never got around to studying it closely.

Interestingly, the females of another genus of fireflies, Photuris, use the flashes of Photinus males to locate and eat them. It has been discovered that the females acquire special steroids called lucibufagins from their prey, which repel spiders.

(While figuring this out, I learned something new. Luciferase, an enzyme responsible for the glow, is extracted from these fireflies. It’s named after the word Lucifer, Latin for “light-bearer.” Interestingly, Greece also had its Lucifer, “light-bearer,” known as the god Phosphorus. Incidentally, the element Phosphorus was discovered by alchemist Hennig Brand through the evaporation of urine. He named the discovered element phosphorus mirabilis, from Latin meaning “miraculous light-bearer.” This just shows how many things in the world are connected.)

A Close Encounter with a Scentless Fawn | June 04 2025, 15:13

I walked with Yuki and he passed by a little deer less than a meter away without noticing. This is a dog that can smell a hare running past the house by scent. It turns out that fawns are born almost odorless, and this saves their lives.

It is precisely because of their nearly complete lack of smell that does leave their young alone for extended periods. Mothers leave fawns for several hours at a time during the first weeks after birth so that their own smell does not transfer to the babies. During this time, the mother returns several times a day to feed her young. Although she may not be continuously near the fawn, she is usually somewhere close by, and surely worried about seeing us around her baby.

However, it’s not only the lack of smell that helps fawns remain hidden from potential predators. The white spots on their fur are another protective measure. When a fawn walks, the spots may seem obvious, but when the mother leaves it to hide in tall grass or other covers, these spots mimic dappled sunlight falling on the forest floor, as noted by the Iowa Department of Natural Resources. Such spotted coloring, combined with the faint smell, makes it difficult for predators to find fawns. Typically, the spots disappear by winter when young deer are old enough to survive on their own.

It is said that fawns are born in late May-early June. Today is precisely June 4. They’re right on schedule!

Despite the fact that he is lying in the open sun in thirty-degree heat, overall, if necessary, he can move on his own. Fawns are born generally ready for life in the wild and are generally able to run immediately after birth (albeit poorly).