It is time once again for "Hey, Science," our world-renowned feature in which we enlist real live scientific experts to answer humanity's most provocative/ dumb scientific questions. Today: Do unknown sea monsters still lurk in the deep?

Today's question, more specifically: How likely is it that there are still large (say, giant squid-sized or better) "sea monsters" that have yet to be discovered by science? Is it realistic to believe that huge new creatures from the deep could still be found? Or have we pretty much exhausted the monster mysteries of the oceans?

Gustav Paulay, curator of marine malacology, Florida Museum of Natural History:

There is a good chance that some pretty large animals remain undiscovered in deep oceans. A good example of this are the beaked whales, a group of cetaceans that is hard to encounter and new species keep getting discovered. An especially cool example is an undescribed beak whale that is being eaten in the Kiribati islands (see here).

Large invertebrates are commonly found of course, but few are giant squid sized. I would think that large fish could remain undiscovered; the megamouth shark was a good example of that a couple of decades ago.

Timothy Essington, professor of aquatic & fishery sciences, University of Washington:

Given the vastness of the ocean, I would not be at all surprised if someday some intrepid explorer discovered some bizarre new form of sea life that we never thought possible. It might be some creature of enormous size, a radically new body design, or some unique way that it "makes a living."

Paul Yancey, professor of deep sea biology, Whitman College:

The answer is: yes, it is possible. The key point here is that humans have only surveyed perhaps 5-10% of the oceans, and even lower percentage of the deepest oceans. New species are being found all the time, some of them fairly large. In fact, new species of whales, very large animals which live at or near the surface, were found as late as the second half of the 20th century. The giant (6-ft) Riftia tubeworms of hydrothermal vents were discovered in 1977.

In the deep sea, new large (but not sea-monster-gigantic) species that have been found in the 21st century include:

1. Big Red jellyfish

2. Pink Meanie jellyfish (tentacles up to 70 ft long)
3. Spaghetti squid

More large species of slow gelatinous animals like jellies and siphonophores seem the most likely to be discovered in the future. It seems less likely that the type of sea monster you are suggesting, like a truly massive squid, might still be left to be discovered. But we just don't know enough to be sure.

Stephen Palumbi, professor of marine sciences, Stanford:

Hi Hamilton, funny you should ask. I have a new book coming out in a month or so called The Extreme Life of the Sea [promo video here], and in it we have a short pondering about such things. The main way we know about giant squid, for example is that they 1) leave scars on sperm whales, and 2) leave their beaks in sperm whale stomachs (not voluntarily). What if there were a even more giant squid that was able to avoid sperm whales? Would we know? I think the answer is "not always":

"Where are the truly huge specimens, like those Captain Nemo fought on the deck of his Nautilus? It is possible that exceptional individuals exist, somewhere in the ancient blackness beneath the planet's seas, hidden under ice caps, or among the volcanoes of the vast Pacific. If a creature grew beyond the strength of the largest whales, no mysterious squid beaks would appear as gastric evidence of the existence of a third giant squid species. If it lived its life in the hidden vastness of the deep sea, avoiding submarines, we'd have no way to know about it. Imagination will always tempt us more than reality: we'll always draw monsters on the margins of maps." (Extreme Life of the Sea, p. 61).

The deep ocean is the biggest life zone in the known Universe. For a rare animal, it may still be possible we have not run into it yet. If it never washes up - if it never gets counted in gut contents - and if it avoids fishing nets and submarines - we maybe haven't seen it yet.

The Verdict: The ocean is vast, and much of it remains unexplored. Large new creatures are still discovered on a fairly regular basis. Are undiscovered sea monsters still possible and plausible? Absolutely. Is it likely they're out there? You'll just have to see for yourself.



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[Image by Jim Cooke]