> Which of the following ocean creatures looks like a squid with a shell?And the answer is: nautilus.Photo credit: USFWSFound in coastal reefs around Southeast Asia and Australia,the nautilus is a type of cephalopod, which is a group of animals that includesthe squid, octopus, and cuttlefish. One noticeable characteristic is that mostof the nautilus' body is contained inside a spiral shell, which makes swimming alittle awkward, but manageable.The nautilus is an ancient creature. These shelled cephalopods have beenperusing the ocean's deep waters for around for some 500 million years, yettheir unique anatomy makes them a continuous source of intrigue in thescientific community. Interestingly, the nautilus is what's known as a "livingfossil" as due to the fact that their anatomy has gone relatively unchanged inthe millions of years they have been on Earth. Unlike squids or octopi, the nautilus do not hunt for their prey. The creaturespropel themselves forward by using water pressure with the chambers of airtrapped in their shell– operating not unlike a submarine. As a result, nautilus'swimming ability is meager at best; they are unable to lunge or attack the sameway as their shell-less cousins. Instead, these cephalopods' way of life dependson scavenging. Helpfully, they have up to 90 retractable, suckerless tentaclesto help in obtaining food and attaching to the reef during rest.The nautilus lay few eggs, and experience a relatively latent maturity– thesecreatures reach their peak after about 20 years of life. However, this makesthem prime subjects for overfishing. The ancient nautilus faces endangermentinto the modern day. Yet, there is still much to learn. Scientists will continueto study their habits and life for as long as they're around. Check out this[https://www.amnh.org/explore/videos/kid-science/how-is-a-nautilus-different-from-a-squid] Museum of Natural History video to learn more.