Question 1

True or false: Nautilus has eight arms like an octopus.

Accepted Answer

False. Nautilus has around 90 tentacles, not eight. Octopuses have eight arms, but nautiluses belong to a different cephalopod group.

Question 2

True or false: Nautiluses can jet propel themselves backward by expelling water through a siphon.

Accepted Answer

True. Like other cephalopods, nautiluses use a muscular siphon to shoot water for jet propulsion, though they are slower than squid or octopus.

Question 3

True or false: Nautiluses have up to 90 tentacles, but they lack suckers.

Accepted Answer

True. They possess many thin, sticky tentacles (cirri) without suckers, used for grasping prey and sensing the environment.

Question 4

True or false: Nautilus has a hard outer shell that it cannot retract into.

Accepted Answer

False. Nautilus can fully retract its body into its shell and close the opening with a protective hood. The shell is a permanent home.

Question 5

True or false: The nautilus uses gas-filled chambers in its shell to control buoyancy, similar to a submarine.

Accepted Answer

True. By adjusting gas and liquid levels in its shell chambers via a tube called the siphuncle, the nautilus can rise or sink with precision.

Question 6

True or false: Nautilus has a well-developed sense of smell used to locate food.

Accepted Answer

True. Nautilus uses chemoreceptors on its tentacles and a specialized olfactory organ to detect prey in the deep ocean.

Question 7

True or false: Nautilus can release a cloud of ink to confuse predators.

Accepted Answer

False. Unlike most cephalopods, nautiluses lack an ink sac. They rely on their shell for protection, not ink.

Question 8

True or false: The nautilus is a living fossil that has remained unchanged for over 500 million years.

Accepted Answer

False. While nautiloids date back 500 million years, modern nautilus species evolved more recently and have changed, though they look similar to ancient forms.

Question 9

True or false: Nautilus eyes lack lenses and work like a pinhole camera to form images.

Accepted Answer

True. Nautilus eyes are primitive and open to the sea through a tiny hole, creating a sharp but dim image, unlike the complex eyes of other cephalopods.

Question 10

True or false: Nautiluses can regenerate lost tentacles and even parts of their shell.

Accepted Answer

False. Nautiluses cannot regenerate shell damage; they only add new chambers. Tentacle regeneration is limited compared to octopuses, which regrow fully.

Question 11

True or false: Nautilus is considered a living fossil with little evolution over 500 million years.

Accepted Answer

True. Nautiloids date back 500 million years. Modern nautilus shells closely resemble fossil ancestors, earning them the 'living fossil' label.

Question 12

True or false: Nautilus controls its buoyancy by adjusting gas and liquid in its shell chambers.

Accepted Answer

True. Nautilus has a chambered shell. It regulates the ratio of gas to liquid in these chambers to ascend or descend in the water column.

Question 13

True or false: Nautilus is commonly found in shallow tropical waters near the shore.

Accepted Answer

False. Nautiluses inhabit deep ocean slopes, typically at depths of 100 to 800 meters. They are rarely seen in shallow waters.

Question 14

True or false: Nautiluses are found in all oceans worldwide, from shallow reefs to the deep sea.

Accepted Answer

False. Nautiluses are restricted to the Indo-Pacific region, typically in deep slopes of coral reefs, not globally distributed.

Question 15

True or false: Nautilus has up to 90 tentacles arranged in two circles around its mouth.

Accepted Answer

True. Nautilus possesses about 90 small, suckerless tentacles. This distinguishes it from octopuses and squids, which have eight or ten arms.

Question 16

True or false: Nautilus shells are made entirely of aragonite, the same mineral found in pearls.

Accepted Answer

True. The shell’s outer layer is aragonite, but inner chambers also contain nacre (mother of pearl), making it strong and iridescent.

Nautilus Trivia Questions