The Question: I came upon these while at a waterfall in Tennessee. Any help finding out what they are would be appreciated. Submitted by: Starlon, Tennessee, USA

The Short Answer: These are the eggs of a toad in the genus Anaxyrus. According to amphibian egg expert Ronald Altig, who studies the development of amphibians at Mississippi State University, they are most likely the eggs of the American Toad (Anaxyrus americanus). The jellylike structure, with prominent black centers, is a clear indication of amphibian eggs, and the long string of eggs makes it a good bet to be one of North America’s toads.

More Information: An interesting question, and one that Dr. Altig feels is under-researched, is why some amphibians lay their eggs in strings, others lay their eggs in sheets, and yet others lay eggs in clumps. According to Dr. Altig, “John Moore in 1940 is about the only one to ever comment on the significance of egg membrane configurations. People ignore eggs like they were either dangerous or totally inconsequential. Also, people tend not to collect things they cannot identify easily and eggs are paramount in this situation.”

Seventy years ago, John Moore suggested that laying eggs in clumps should provide protection from predators and from cold for at least some of the eggs, since a predator has to get through the entire mass of jelly to get at the very interior eggs. And the outer eggs and jelly provide some insulation to keep the innermost eggs from freezing. So he predicted that clumps of eggs would be laid by amphibians that lay early in the season, when there is a danger of extreme cold. One problem with a clump is that getting oxygen to the innermost eggs becomes a problem. But cold water holds more oxygen than warm water, so that is less of a problem for amphibians that lay in cold water. Laying eggs in a sheet on the surface of the water, by contrast, might make sense for amphibians that lay in warm, oxygen-poor water.

For the most part, these criteria seem to work, although not perfectly. And Moore never presented a theory that would account for strings of eggs. Dr. Altig’s suggestion is that a string affords the most surface area for oxygen exchange in stagnant water that has very little oxygen. This would apply to most North American toads. Of course, the American toad eggs you found were laid in a highly oxygenated waterfall pool, but it’s possible that the eggs are really adapted for warm water and low oxygen, because that’s the most challenging environment where American toads lay their eggs.

Sources: Thank you to Dr. Catherine J. Hanna and Dr. Altig for help in identifying these eggs.

Tom | Animals, Questions and Answers, Uncategorized | 05 17th, 2012 | Click to Leave a Comment »

The Question: I found these creatures in mud. They were approximately 30 cm (1 ft). The head is 4-5 mm (0.25 inch) in diameter. They don’t look like worms. I wonder if they might be snakes. What are they and what do they eat? Submitted by: Madhumita, Chhattisgarh, India

The Short Answer: This is definitely a synbranchid fish, most likely Monopterus digressus.  The synbranchid eels are known collectively as “Asian swamp eels.”  The Asian swamp eels are famous for their ability to survive and thrive in environments that most of us wouldn’t think of as suitable for fish.  Monopterus digressus has been found in newly dug underground wells, which seems impossible, but it’s believed they live in and swim through the small underground channels through rock that connect subterranean waters.  Like many other animals that live underground or in caves, they don’t have functional eyes.  They also lack fins.

I have previously written about another Asian swamp eel, Monopterus cochia: http://askanaturalist.com/what-is-this-eel-like-fish-from-india/

Monopterus albus, another synbranchid eel, has been introduced to Hawaii and Florida and is of concern as a possibly destructive invasive species: http://fl.biology.usgs.gov/Nonindigenous_Species/Swamp_eel_FAQs/swamp_eel_faqs.html

More Information: As to your question about what they eat, it’s difficult to study these creatures in their natural habitat, but they are definitely predatory and probably would eat worms, insects, and any other animals small enough to fit into their mouths.  An investigation of their feeding habits involved feeding them both chopped earthworms (Oligochaeta) and brine shrimp (Artemia).  The eels seem to locate prey by smell and then, when close enough, by touch.  The instant a prey object touches the fish’s head, it immediately engulfs it.  If you still have this fish, I suggest you try different live foods until you find a few that it will eat regularly.

Sources:  Thanks to Marcus Knight, Moncey Vincent, GK Bhat, and Mark Wilkinson for help in identifying this fish.

Vincent, M and Thomas, J. (2011). Observations on the foraging behavior of a subterranean fish Monopterus digressus (Synbranchiformes: Synbranchidae). Ichthyology Research, 58:95-98.

Vincent, M.  (2012).  Occurrence, distribution and troglomorphisms of subterranean fishes of peninsular India.  Current Science, Vol. 102, No. 7, 1028-1034.

Tom | Animals, Questions and Answers, Uncategorized | 05 13th, 2012 | Click to Leave a Comment »

The Question: This spider crawled out of a vent at my daughter’s home and moved quickly towards the door where she opened it and watched it go outside. My daughter is terrified and wonders if she needs an exterminator? Is this spider venomous? She’s scared to have her baby on the floor. Please help identify this creepy crawler. Submitted by: Jojo, Calgary, Alberta, Canada

The Short Answer: Unfortunately, this photograph doesn’t show much detail, so we haven’t given Mandy Howe from www.spiders.us much to go on. But her guess is a female giant house spider (Tegenaria duellica, previously known as Tegenaria gigantea), also known as the greater European house spider. Mandy told me:

“Alberta has Tegenaria duellica as well as Tegenaria atrica and they are essentially twins on the outside, so it’s impossible to tell from an image which is which but they have the same habits and personalities. They are very large when full-grown and can run really fast, but are very docile and not considered dangerously venomous to people. They are a European import and are fairly common in and around homes in some of the Canadian provinces as well as the Pacific Northwest of the U.S.

“This kind of spider uses a web to catch its prey (insects and other spiders), so they depend almost entirely on vibrations rather than their poor eyesight. My guess is that the spider was disturbed from its web or was not finding enough food at its current location, so it moved on… these spiders run along the baseboards in homes (sticking to the outsides of rooms, almost like mice do), so her escaping out the door as the reader opened it was most likely a coincidence, as the spider was running scared and blind.”

Here’s a better picture of the giant house spider. You can see that it has a very similar shape and posture to your photo.

More Information: The giant house spider is closely related to the more infamous hobo spider (Tegenaria agrestis). They and other spiders in the same genus (Tegenaria) look very similar. And these spiders certainly are large. A female hobo spider’s body is 11-15 mm (1/2 inch) long. A female giant house spider’s body is 16-18 mm (3/4 inch) long and its leg span can be nearly two inches. Males have smaller bodies, but can have longer legs, with a leg span of nearly three inches! Seeing a spider that big crawling across the floor will get most people’s attention.

Many people think the hobo spider is both aggressive and venomous, and you can find many websites that insist that hobo spiders cause necrotic wounds (wounds that fester and cause tissue death). However, this is all based on a single study that has proven to be unrepeatable. Like the giant house spider and other Tegenaria spiders, the hobo spider is highly unlikely to bite and despite its reputation, does not appear to cause serious wounds. A study reported in the Journal of Medical Entomology in 2011 showed that there are no compounds in the bite of a hobo spider that are likely to cause serious wounds. Another theory is that hobo spiders introduce bacteria, but a complete culture of all bacteria found on dozens of hobo spiders showed only common bacteria typically found in the environment. Because there have been rumors that hobo spiders carry MRSA (Methicillin-resistant Staphylococcus aureus), an antibiotic-resistant bacteria that is a public health problem, the researchers exposed hobo spiders to MRSA to see if they picked it up from the environment and could therefore introduce it in a bite, but even after exposure, there was no evidence of MRSA on the hobo spiders.

These spiders, both hobo spiders and giant house spiders, are native to Europe, where they have lived in people’s houses for centuries. They were introduced to North America in the 20^th century. Oddly enough, in Europe they don’t have a reputation for being aggressive or dangerous, which suggests that their North American reputation could be a myth.  To see a video of a child letting a giant house spider walk all over her hand, go to http://www.youtube.com/watch?v=xxNpitlKc_s&feature=youtu.be.

People’s fears of spiders are largely unfounded.  Mandy reports that she has handled giant house spiders and many other species for decades without EVER being bitten.  I have picked up and removed hundreds of spiders of all kinds from my house over the years and have never been bitten.  You are far more likely to be bitten by an ant.

So whether the spider in Jojo’s daughter’s house is a giant house spider or a hobo spider, there is little to fear from these spiders. In my opinion, with a baby in the house, I’d be more worried about using pesticides to exterminate spiders than about the spiders.

Sources:

Gaver Wainwright, M, Zack, R S, Foradori, M J, et al. (2011). Misdiagnosis of spider bites: Bacterial associates, mechanical pathogen transfer, and hemolytic potential of venom from the hobo spider, tegenaria agrestis (araneae: Agelenidae). Journal of medical entomology, 48(2), 382-388.

Tom | Animals, Questions and Answers, Uncategorized | 05 10th, 2012 | 1 Comment »

The Question: I saw these wildflowers in the central California Valley near Aptos. They are about the size of a quarter. What are they? Submitted by: Alan, California, USA

The Short Answer: Your flowers are definitely one of several species of poppies in the genus Eschscholzia found in California. Most probably they are Eschscholzia lobbii, also known as the frying pan poppy and Lobb’s goldenpoppy. However, according to Curtis Clark, expert on Eschscholzia poppies at the California State Polytechnic University in Pomona, Aptos is outside the normal range of the frying pan poppy. “Although there are specimens of E. lobbii outside my range map, none are anywhere close to Santa Cruz County. Looking at the photo, it does resemble E. lobbii (and is definitely not E. californica), but another possibility is E. hypecoides. There are diagnostic features of the foliage (E. lobbii has long pointed tips to the leaf divisions, and the leaves are predominately basal, whereas E. hypecoides has relatively blunt, short tips and the flowering stems are leafy), but I am not able to see those in the photo.

“Another possibility is that it could be an escapee from cultivation. E. lobbii seeds are sold under the scientific name, the common name ‘frying pans’, and sometimes even as ‘Eschscholzia caespitosa’, which is a different species.”

More Information: There are twelve species of Eschscholzia poppies, which are in the same family (Papaveraceae) as the more famous Opium poppy, Papaver somniferum. The Eschscholzia poppies are found throughout California and the southwestern U.S. down into Mexico and Central America. Both the frying pan poppy and the more widespread California poppy have also become common garden flowers. To tell the California poppy from all the others, look for a rim on the receptacle, which is the part of the flower stalk that flares out where it attaches to the flower. As shown in this photo, the California poppy has a distinct rim under the flower. In frying pans and all the other Eschscholzia poppies this rim is very small or absent.

By the way, while the Eschscholzia poppies don’t contain the substance we call opium, they have their own psychoactive chemicals, so it’s best not to ingest them, in case you were wondering.

There is a wealth of information about all the Eschscholzia poppies to be found at Dr. Curtis Clark’s website: http://www.csupomona.edu/~jcclark/poppy/index.html.

Thanks: Thanks to Briar and Champion at www.flowersforums.com who responded quickly to my question asking if this was E. lobbii, and to Dr. Curtis for his help.

Tom | Plants, Questions and Answers | 04 29th, 2012 | Click to Leave a Comment »

The Short Answer: According to Avibase, the one duck that is occasionally seen in parts of coastal Antarctica is the yellow-billed pintail (Anas georgica). This was confirmed for me by Dr. Peter Convey with the British Antarctic Survey who added that “There are no breeding ducks on the Antarctic mainland (continent or Antarctic Peninsula and offshore archipelagoes).”

So it sounds like the yellow-billed pintail is your mystery duck. It occasionally vacations in Antarctica, but doesn’t stay long enough to breed.

The yellow-billed pintail is one of the most common ducks in South America and is found over most of the western and southern parts of the continent, excluding the Amazon and other rainforest areas. There is also a well-known subspecies, the South Georgia pintail (Anas georgica georgica), which is found primarily on South Georgia, one of the southernmost islands that is not considered to be part of the Antarctic continent. On South Georgia, the ducks are primarily nocturnal and eat shrimp, amphipods, other crustaceans, snails and other invertebrates, as well as marine algae. The nocturnal feeding habits may be an adaptation to predation by the Antarctic skua (Stercorarius antarcticus), a large seabird which catches adult ducks on the fly during daylight hours.

January being summer in the Southern Hemisphere, we are currently in the breeding season for the yellow-billed pintail. The population on South Georgia typically lays five eggs, with two or three clutches possible in a season. In the 19^th century, the South Georgia pintail was hunted by the crews of whaling vessels, and these days, they suffer from predation by introduced rats, but the population seems stable.

More Information:

Sharing South Georgia Island with the South Georgia pintail is the speckled teal (Anas flavirostris). Other far southern islands that have ducks include the Falklands (also called the Malvinas) off the coast of Argentina and Macquarie Island south of Australia and New Zealand. Like South Georgia Island, the Falklands have both speckled teals and yellow-billed pintails as well as several other duck and goose species. Macquarie Island has Pacific black ducks (Anas superciliosa) grey teal (Anas gibberifrons) and non-native mallards (Anas platyrhynchos). None of these other species are known to visit Antarctica, however.

Sources:

Janet Kear (2005). Ducks, Geese and Swans, Oxford University Press.

McCracken, K.G. and Wilson, R.E. (2011). Gene flow and hybridization between numerically imbalanced populations of two duck species in the Falkland Islands. PLos ONE, 6(8).

Catalogue of Australian Antarctic and Subantarctic Metadata: http://gcmd.nasa.gov/KeywordSearch/Metadata.do?Portal=amd_au&KeywordPath=[Keyword%3D%27MACQUARIE+ISLAND%27]&NumericId=20602&MetadataView=Full&MetadataType=0&lbnode=mdlb3, accessed on January 20, 2012.

Tom | Animals, Questions and Answers, Uncategorized | 01 23rd, 2012 | 1 Comment »