49 votes
Accepted

How long can an octopus survive out of the water?

Short answer Under ideal conditions, an octopus may survive several minutes on land. Background Octopuses have gills and hence are dependent on water for the exchange of oxygen and carbon dioxide. ...
user avatar
  • 51.2k
20 votes
Accepted

Identification of colorful jelly-like marine creature

You've found a sea anemone, a cnidarian of the Order Actiniaria. In this case, the anemone is closed and thus hiding its characteristic tentacles (likely as a form of protection while "out to dry"). ...
user avatar
12 votes
Accepted

Spider identification

After some more searching, I think stumbled across the answer. It appears to be an… Eriophora ravilla: Source BugGuide.net. This species appears to have quite a diverse range of colors, and ...
user avatar
  • 1,427
11 votes
Accepted

What is this long, thin and segmented insect I found in my house in India?

UPDATE: Based on a comment by ArthurJFrost reminding me of the existence of a group of insects I totally forgot about, AND based on a closer examination of the cerci and what appears to be external ...
user avatar
10 votes

How long can an octopus survive out of the water?

Found an octopus today which had attached itself to a rock covered in algae during high tide and had failed to swim back out with the receding tide. We found it at low tide, this means it must have ...
user avatar
  • 101
9 votes

ID a shell from Puerto Rico

This is the shell of a marine mollusk called a chiton. They are also sometimes known as sea cradles or "coat-of-mail shells", or more formally as loricates, polyplacophorans, and ...
user avatar
9 votes
Accepted

What are these tiny creatures swimming around my aquarium?

Hard to tell because of the poor picture/video quality, but almost immediately the body shape, distinct "face", size and behavior made me think of a small invertebrate animal called a ...
user avatar
8 votes

Can you identify this fossil?

It's a sea urchin (Echinoidea). It looks like a specimen of Lovenia or another genus from the heart urchin (Spatangoida) family. What you see is just the shell without the spines. Lovenia woodsii ...
user avatar
  • 2,048
8 votes
Accepted

What are these bladder snail parasites?

I have finally figured out what these are, and it turns out I greatly misunderstood their relationship with snails. These worms are annelids of the genus Chaetogaster, specifically Chaetogaster ...
user avatar
  • 473
7 votes
Accepted

What is the largest species of polychaete?

According to the Smithsonian: The longest of all known polychaetes was found in Port Jackson, Australia. It was a member of the family Eunicidae, consisted of approximately 1,500 segments and was ...
user avatar
6 votes
Accepted

Species identification - greenish blue ocean worm (nudibranch?) in Perhentian Islands, Malaysia

It's hard to identify from the photos provided, but I think it is Chloeia flava (a species of polycaete worm, within the phylum Annelida), also known in English as the "Golden Fireworm". The size is ...
user avatar
  • 1,007
6 votes
Accepted

What happens to a snail if we cut off its antennae?

It really depends on which type of gastropod you are talking about, since different types of snails, have different types of eyes. Marine gastropods could only become more mobile, when their ...
user avatar
  • 2,573
6 votes
Accepted

Why do Centipedes always have an odd number of pairs of legs?

Centipedes are part of the group of insects that utilize a short germ-band mode of embryonic development.1 One feature of this type of segmentation is that new segments are added sequentially to the ...
user avatar
  • 7,729
6 votes
Accepted

Identification of odd jellyfish-like creature in the Mediterranean

It seems to be a "Hula skirt siphonophore" - Physophora hydrostatica Physophora hydrostatica, also known as hula skirt siphonophore, is a species of siphonophores in the family ...
user avatar
  • 251
5 votes
Accepted

What kind of hot pink eggs are these?

Those appear to be the eggs of a species of apple snail in the genus Pomacea, probably the introduced invasive golden apple snail (Pomacea canaliculata), but there are at least two other candidates1,2....
user avatar
  • 5,296
4 votes

Did radial symmetry evolve twice?

Good question! I had never really though about it, so thank you! Echinodermata have a pentaradial symmetry Echinodermata actually don't have a radial symmetry like jellyfish do. They have a ...
user avatar
  • 67.6k
4 votes
Accepted

Why do crabs spit?

Breathing during digging And if all that wasn’t enough responsibility for these claws, they also are used for digging. While most digging crabs use their back legs to burrow backwards into the sand, ...
user avatar
  • 2,573
4 votes
Accepted

What is the reason behind the subphylum name "Urochordata" for tunicates?

In 1877, Lankester proposed in "Notes on the Embryology and Classification of the Animal Kingdom" division of the group we now call Chordata into three parts: Urochorda Cephalochorda Craniata which ...
user avatar
  • 8,759
4 votes
Accepted

What is this agglomeration of pink cells I found attached to a stone?

They are Apple snail's eggs; check the picture: Check this.
user avatar
  • 357
4 votes

What is this agglomeration of pink cells I found attached to a stone?

This could very well be the eggs from an apple snail (family Ampullariidae). According to Wikipedia Several apple snail genera (Pomacea, Pila and Asolene/Pomella) deposit eggs above the waterline ...
user avatar
4 votes
Accepted

Species identification. Is this a leech?

Yes this is a leech. It appears to be a species in the family Glossiphoniidae, or the freshwater jawless leeches. This family of leeches is relatively flattened with a poorly defined anterior sucker. ...
user avatar
4 votes

strange creature

It is a penis worm! https://en.wikipedia.org/wiki/Priapulida Priapulida (priapulid worms, from Gr. πριάπος, priāpos 'Priapus' + Lat. -ul-, diminutive), sometimes referred to as penis worms, is a ...
user avatar
  • 2,926
3 votes
Accepted

How do you determine the length of an annelid?

Leeches: According to Taube (1966)$^1$: The adults of American leeches range from about 1/4 inch to 12 inches in contracted length. Because leeches can bloat to more than 10x their "normal"...
user avatar
3 votes
Accepted

Are there any theories why such an imbalance in chirality of molluscs?

Why so many molluscs exhibit sinistral winding? The estimates of the number of molluscs vary quite greatly between 50,000 and 200,000 species. Of those molluscs species, about 70'000 are Gasteropoda. ...
user avatar
  • 67.6k
3 votes
Accepted

will an earthworm survive after covering its skin with a wet cloth

This is one of those speculative questions where you don't have a definite answer unless you specifically experiment and find out for yourself. It is a known fact that earthworms breathe through ...
user avatar
3 votes

Are there echolocating insects?

My understanding (as a PhD holder in toothed whale echolocation) is that insects do not use echolocation themselves as a means of hunting or sensing their environment more generally, but some do ...
user avatar
  • 129
3 votes

Do octopuses have better eyes than humans?

Adding to the answer above, another advantage of cephalopod eyes is the lower risk of retina detachment. (HumanEvolution) Also, cephalopod eye focus image by moving the lense (like a camera or ...
user avatar
3 votes

Help in identifying an unknown Golden Worm/Larvae

These are larvae of the so called fungus gnat of the order Diptera. Fungus gnats are small flying insects that look sort of like mosquitoes but they don’t bite. In fact, adult fungus gnats live only ...
user avatar

Only top scored, non community-wiki answers of a minimum length are eligible