Biology
The Genetic Basis of Melanism and Thermal Adaptation in Rock Pocket Mice
Quick fact
In rock pocket mice, a single mutation in the Mc1r gene can turn a light-colored mouse into a dark one, and this color change is strongly favored by natural selection on dark lava rocks—but it may also come with a cost: dark fur absorbs more heat, creating a trade-off between camouflage and thermoregulation.
Why this is interesting
You might have seen light-colored mice scurrying in the desert, but on dark volcanic rocks, some mice are black. Why did they evolve such a striking difference, and what does it have to do with staying cool?