Toe-tally mysterious

Hairs on the toes of Mexican free-tailed bats light up under ultraviolet light, but the reason is unknown, Jason Bittel reported in “Mexican free-tailed bats’ toes glow in the dark” (SN: 8/28/24).

Reader Eleanor Peterson asked if the glowing toes might attract prey.

It is unlikely, but it is a logical thought, says biologist Fernando Gual-Suárez of the National Autonomous University of Mexico in Mexico City. Many organisms, such as some anglerfish and cave insects, use photoluminescence to lure prey. But unlike those life-forms, which are sit-and-wait predators, bats “are active aerial hunters,” Gual-Suárez says. What’s more, the photoluminescent toe hairs would be difficult for potential prey to see. If these marks were useful for hunting, they would be located near the mouth (think of an anglerfish’s lure, for example), and the bats would “use a different hunting strategy,” he says.

More studies are needed to know the marks’ function, Gual-Suárez says. The photoluminescence could serve no function and simply be a byproduct of the hardened structure of the hairs, which are used for grooming or sensing. Or it could be used to communicate with other bats during flights or roosting, he says.

Diving deep on decay

Scientists spotted the rare “golden channel” decay of subatomic particles called kaons. Further studies could break or bolster the standard model of particle physics, Emily Conover reported in “Rare particle decay confirmed” (SN: 9/24/24).

Reader Derek Lenehan asked how the decay might stray from the standard model.

If the decay strays from standard model predictions, it would point to new physics that is largely unknown. In this decay, a kaon produces a pion, a neutrino and an antineutrino. But other particles called W and Z bosons mediate the decay, says particle physicist Cristina Lazzeroni of the University of Birmingham in England. In new physics scenarios, some physicists have proposed new particles that could act as intermediaries, such as a Z’ (pronounced “Z prime”) boson. Another is a leptoquark, a particle with properties similar to electrons and their lepton relatives and to quarks — the particles that make up protons, neutrons and other composite particles.

Correction

The graph in “Earth’s temperature highs and lows” reversed the labels for curves showing global temperature and atmospheric CO₂ data (SN: 9/19/24). Both curves also showed fifth-percentile values rather than the average (50th-percentile) values. The correct version is shown here.