1. Cockroaches can survive under nuclear radiation: Cockroaches have a very strong resistance to radiation and can even survive in environments with nuclear radiation.

2. Crocodile tear glands: Crocodiles shed tears before swallowing their prey. This is because crocodiles secrete a type of tear fluid while eating, which helps lubricate the food and makes it easier to swallow.

3. Owls' turning: Owls have very flexible necks, allowing them to turn almost completely behind them, which is an advantage when they hunt.

4. Human sense of smell: The human sense of smell can remember 10,000 different smells, and olfactory memory is more durable than visual memory.

5. Blue whale's tongue: The blue whale's tongue weighs the same as an elephant's, making it the heaviest tongue in the animal kingdom.

6. The composition of pencils: Pencil lead is not made of lead, but is made of a mixture of graphite and clay.

7. Lifespan of yeast: Yeast can survive for decades or even longer under suitable conditions.

8. Nail growth rate: On average, human nails grow about 1/8 inch (about 0.3 cm) per month, while toenails grow at half the rate of fingernails.

9. The brain during sleep: During deep sleep, the brain clears away waste products that have accumulated throughout the day.

10. Potassium content in bananas: Bananas are very high in potassium. Eating one banana provides about the same amount of potassium as eating four carrots.

These little-known facts are just a part of the many interesting things in life, reminding us that even the most ordinary things hold endless mysteries and fun.