Quirks & Quarks has been taking your burning science questions for half a century. And while we thought we might have answered every question there is to answer over the years, our listeners proved there are always more fascinating head-scratchers for us to tackle.

Like:

• Are comets eternal?
• In a sauna, what am I sweating out?
• Did dinosaurs produce milk?
• If heat rises, why is there snow on the top of mountains?
• What does a black hole orbit?
• What if we had no moon?
• Why are cat and dog tongues so different?
• Why are robin eggs so blue?
• Why do some animals become mega sized?
• How do animals deal with strong bright UV light?

Some of the oceans biggest, most powerful predators, like certain sharks and tuna, are “mesothermic” or warm-bodied. Running hot allows them to rapidly convert their food to energy and heat, helping them swim faster and hunt in cold waters. But that advantage may become a disadvantage in a warming climate, meaning these fish need to find new ways of cooling off, or face a new threat to their survival.

PLUS:

• Ancient Peruvians traded parrots across deserts and mountains
• From the archive: David, Jay and Bob, and Quirks & Quarks' origin story
• Sea cucumber 'zombie tissue' straddles the line between life and death
• Dream engineering may help you solve problems in your sleep

Gold miners working in the Yukon regularly find ancient ground squirrel burrows throughout the permafrost, many containing fossilized feces. Researchers analyzing these well-preserved poop piles found they contain some of the oldest DNA ever recovered, dating from 30,000 to 700,000 years ago. Tucked inside were traces of a wide range of ancient animals, including woolly mammoths, grasshoppers, steppe bison, ancient horses, American cheetahs, as well as hundreds of plant species.

PLUS:

• ‘Super-good, ice-making microbes’ may trigger snow and rain, or help freeze food
• We’re a hotbed of mutations, and scientists are leveraging that for our health
• Going out on a limb. Animals regrow body parts, maybe we can too
• From the archives: Isaac Asimov on human creativity and robots