1. What Is a Nautilus?: A nautilus is a fascinating, ancient marine animal with a soft body tucked safely inside a gorgeous, spiral-shaped shell.

2. Swimming Living Fossils: Nautilus creatures have been cruising the oceans for over 500 million years—meaning they were swimming around the deep sea long before dinosaurs ever walked the Earth!

3. The Ultimate Spiral Shell: The nautilus shell is famous for its perfect mathematical spiral shape, where each new chamber grows larger than the last in a precise pattern known to scientists as the golden ratio.

4. Dozens of Tiny Tentacles: Unlike their squid and octopus cousins that only have eight or ten arms, nautiluses have up to 90 tiny, suction-cup-free tentacles that they use to grab food and feel their way along the dark ocean floor.

5. Built-in Submarine Tanks: To swim up or down, the nautilus uses its shell like a submarine! It pumps water and gas in and out of the different chambers inside its shell to control how it floats or sinks.

6. Living in the Deep Dark: Nautilus creatures hang out in the deep, dark tropical waters of the Pacific and Indian Oceans during the day, coming up to shallower waters only at night to search for food.

7. Nature's Ultimate Survivors: Because they live deep underwater and can seal themselves tightly inside their hard shells with a tough, leathery hood, nautiluses have survived massive extinction events that wiped out countless other ancient animals.