Category Archives: Fish, Frogs

Red Spots That Warn and Attract

Adult eastern newt swimming (photo from Wikimedia Commons)

10 March 2024

Last Thursday I went looking for fairy shrimp(*) at Todd Nature Reserve and found amorous red-spotted newts (Notophthalmus viridescens) instead. The newts attracted my attention because I had never seen adults before, let alone their courtship.

When you think “red-spotted newt” you probably visualize the red eft, the juvenile terrestrial, dry-skinned phase that lasts 1-3 years. Since red-spotted newts can live up to 15 years this phase is not a high percentage of its lifetime, but it is unforgettable.

Red eft, juvenile phase of the red-spotted newt (photo from Wikimedia Commons)

Red efts wander fearlessly overland because their bright orange color and red spots outlined in black are a warning to predators: “Don’t eat me! You’ll regret it.”

Red eft on a mossy rock (photo from Wikimedia Commons)

The skin of juveniles and adults secretes tetrodotoxin (TTX), the same neurotoxin found in pufferfish that causes paralysis and death.

According to Wikipedia, TTX “can enter the body of a victim by ingestion, injection, or inhalation, or through abraded skin.” But this hasn’t stopped anyone from holding red-spotted newts. Apparently this activity is just fine.

Red eft in hand at Dolly Sods (photo from Wikimedia Commons)
Adult red-spotted newt in hand (photo from Wikimedia Commons)

Fortunately people don’t eat newts except …

Poisonings from tetrodotoxin have been almost exclusively associated with the consumption of pufferfish.” … [In North America there is] at least one report of a fatal episode in Oregon when an individual swallowed a rough-skinned newt (Taricha granulosa) on a dare.

Wikipedia: Tetrotodoxin

The red spots warn predators. They also attract female newts during the breeding season.

Courtship in newts is fascinating. The male will lure and entice the female with his many red spots and wiggling tail, which releases pheromones (specialized chemicals). The male, with his hind legs, will grasp the female just behind her forelimbs and then rub his chin along her snout just prior to external fertilization.

Connecticut Dept of Energy and Environmental Protection: Red-spotted newt

She likes his red spots. He embraces her.

Courtship of red-spotted newts (photo by Judy Walls linked from Vermont Reptile and Amphibian Atlas)

It’s very sweet to see this in Spring.

(credits are in the captions)

(*) p.s. Click here to learn about fairy shrimp.

Seen This Week

Sunny and 75 degrees at Schenley Park, 4 March 2024 at 4pm (photo by Kate St. John)

9 March 2024

The weather doesn’t know what to do with itself in Pittsburgh. Some days it rains all day (today for instance). Some days it’s hot and sunny. Some days it’s chilly and overcast. This week we saw it all.

On Monday and Tuesday hot sunny weather (74-75°F) encouraged everyone to get outdoors. I waited a while to get a photo, above, without a lot of people in it. Just around the bend the sun was so low in the sky at 4:40pm that it made long shadows.

Long shadows and 75 degrees at Schenley Park, 4 March 2024 at 4pm (photo by Kate St. John)

That beautiful day came after a foggy rainy weekend, seen at Duck Hollow below. The Monongahela River was running high because of all the rain.

Duck Hollow, 2 March 2024 (photo by Kate St. John)

All kinds of critters were busy this week including a striped red ant on a trail in Schenley Park. What ant is this? Can you tell me its name?

Striped red ant, Schenley Park, 4 March 2024 (photo by Kate St. John)

On Monday I also found two refugees from water-logged soil on a sidewalk in Oakland. Not earthworms, these are invasive Asian jumping worms. Not good! Click here to see a brief clip of them squirming.

Asian jumping worms on the sidewalk on Craig Street, 4 March 2024 (photo by Kate St. John)

On Thursday 7 March I found new leaves of (maybe) corydalis at Todd Nature Reserve.

New corydalis leaves? Todd Nature Reserve, 7 March 2024 (photo by Kate St. John)

And on the way home I stopped at the Tarentum Bridge to check on the peregrines. The male was perched nearby while the female incubated eggs in the nest. This (lousy) digiscope photo shows the female’s wingtips visible in the nest box as she incubates with her tail toward us. This is early for most peregrines in southwestern PA but not for this bird. She’s always early.

Female peregrine incubating at the Tarentum Bridge nest, 7 March 2024 (photo by Kate St. John)

p.s. Don’t forget to turn your clocks AHEAD tonight. (egads! I fixed that awful typo. Thanks, everyone, for pointing it out.)

Upset Clock (photo by Kate St. John)

(photos by Kate St. John)

It’s Time to Look for Fairy Shrimp

Vernal pool in late winter (photo from Wikimedia Commons)

27 February 2024

Yes, it’s still February but this winter has been so warm that it’s already time to look for shrimp in the woods.

Last year Adam Haritan at Learn Your Land taught us about fairy shrimp in vernal pools. If you missed his 7-minute video, view it right now to find out what these tiny creatures look like and where to find them.

video embedded from Adam Haritan’s Learn Your Land

Amazingly there are 313 species of fairy shrimp (Ansotraca) around the world. Some live in brine water, some live in freshwater. The Eubranchipus genus which Adam mentioned contains 16 species including this female in Poland. You can see the eggs inside her at the root of her tail.

Fairy shrimp, female, Eubranchipus genus in Poland (photo from Wikimedia Commons)

Are you ready to go look for fairy shrimp? Find an isolated ephemeral pool in the woods and look for tiny movement in the water. Here’s a photo to set your size expectations. There’s one at the tip of the fingernail.

Fairy shrimp in Oregon (photo from Wikimedia Commons)

Look for vernal pools in the days ahead. In addition to fairy shrimp you’ll find wood frogs and spring peepers. Don’t delay. The end of March may be too late.

(credits and links are in the captions)

Starfish Have No Arms

Common starfish (photo from Wikimedia Commons)

11 December 2023

When you look at a starfish it is obvious that its body is arranged like the five spokes of a wheel. This is also true of its fellow enchinoderms sea urchins and sand dollars.

Sea urchin endoskeleton (photo from Wikimedia Commons)
Sand dollar (photo by Kate St. John)

As larvae starfish are bilateral just like us, but when they grow up they change.

Most animals, including humans, have a distinct head end and tail end, with a line of symmetry running down the middle of their body dividing it into two mirror-image halves. Animals with this two-sided symmetry are called bilaterians.

Echinoderms, on the other hand, have five lines of symmetry radiating from a central point and no physically obvious head or tail. Yet they are closely related to animals like us and evolved from a bilaterian ancestor. Even their larvae are bilaterally symmetrical, later radically reorganizing their bodies as they metamorphose into adults.

NewScientist: Starfish don’t have a body – they’re just a big squished head

Scientists were curious about how the animal formed five arms so they examined the genes on the body surface of the bat star (Patiria miniata) …

Patiria miniata (photo from Wikimedia Commons)

… and were surprised to find that the the entire animal, from center to tips of the arms, expresses as “head” genes. There are no torso or limb genes. As Science Magazine put it, “Genetically speaking, starfish have no arms — only a head.

The findings show that “the body of an echinoderm, at least in terms of the external body surface, is essentially a head walking about the seafloor on its lips”, says Thurston Lacalli at the University of Victoria in Canada.

NewScientist: Starfish don’t have a body – they’re just a big squished head
Starfish – sea star – mosaic showing diversity of the class Asteroidea (photo from Wikimedia)

Read more in NewScientist: Starfish don’t have a body – they’re just a big squished head

On Cape Cod It’s Always Shark Week

Great white shark, South Africa (photo from Wikimedia Commons)

30 July 2023

This may be the last day of Shark Week on the Discovery Channel but on Cape Cod it runs all year. A new study published this week in Marine Ecology Progress Series tagged and counted great white sharks (Carcharodon carcharias) off the coast of Cape Cod, Massachusetts and found that 800 individuals visited the area from 2015 to 2018. That means Cape Cod may have the highest density of white sharks in the world.

Fortunately all the sharks weren’t there at the same time. As lead author Megan Winton of the Atlantic White Shark Conservancy (AWSC) explains, great white sharks are highly migratory. Their population peaks on the Cape from July to November when the water is warm, as shown in this screenshot from AWSC’s logbook for 2022. Individual sharks spend a few hours or a few weeks in the area. (Click here to see AWSC’s shark data and download their shark app.)

AWSC white shark logbook by month for 2022 (screenshot from AWSC)

The sharks are attracted to the Cape by the abundance seals, one of their favorite foods. A Google Haul Out survey of southeastern Massachusetts estimated maximum counts of gray seals at 30,000 to 50,000 animals in 2012 to 2015. Harbor seals arrive in the fall and add to the seal population. No wonder sharks show up. Gray seals provide a lot of meat, weighing as much as 800 pounds.

Gray seals at Nantucket NWR (photo from Wikimedia Commons)
Gray seals at a haul out in Nantucket NWR (photo from Wikimedia Commons)

During our recent trip to Cape Cod I saw lots of seals at Chatham Fish Pier. Several swam by the fishing boats but the vast majority were hauled out on a sand bar across the harbor. See that lumpy line of gray blobs? Those are gray seals.

Gray seals line the edge of the sand bar across from Chatham Fish Pier on Cape Cod, 12 July 2023 (photo by Richard St. John)
Gray seals line the edge of the sand bar across from Chatham Fish Pier on Cape Cod, 12 July 2023 (photo by Richard St. John)

While on the Cape I didn’t see any sharks but I did see a No Swimming shark sign at Race Point. I was looking for birds and, as it turns out, diving seabirds give the hint that a shark may be nearby. Both feed on schools of fish, the birds from above, the sharks from below.

The abundance of sharks and seals in Cape Cod’s waters is an environmental success story. Gray seals were almost extinct in U.S. waters by the mid 20th century because of bounty hunting in Maine and Massachusetts from the late 1800s to 1962. The seal population began to recover, slowly, when the bounties ended. Sharks made a comeback because of the seals.

Learn more in this ABC News interview with lead author Megan Winton of Atlantic White Shark Conservancy.

video embedded from ABC News on YouTube

p.s. Well, technically, it’s only Shark Week for 5 months on Cape Cod — mostly from July to November.

(photos from Wikimedia Commons and by Richard St. John, graph is a screenshot of AWSC’ logbook website; click on the links to see the originals)

Miniature Flying Dragons

Artistic reconstruction of ancient flying lizard, Weigeltisaurus jaekeli (image from Wikimedia Commons)

28 October 2022

Back in the Late Permian, 258 to 252 million years ago, there was a family of gliding lizards called Weigeltisauridae whose fossils have been found in Germany, Britain, Russia and Madagascar. Europeans drew them as dragons.

Winged dragon on the ground, illustration in: Athanasius Kircher’s Mundus Subterraneus via Wikimedia Commons

Today there are still gliding lizards on Earth but they are smaller and live in Asian jungles. Dracos can glide 100+ feet from tree to tree by extending their long skin-covered ribs.

Draco taeniopterus flying and Draco volans skeleton (image from Wikimedia Commons)

Watch one fly to escape a dominant male in this BBC Planet Earth II clip.

Learn about Draco dussumieri of Southern India in this video from Roundglass.

Where do Dracos live? Click on the map caption to see a larger view.

(photos, maps, a video and illustrations from Wikimedia Commons; click on the captions to see the originals. videos also embedded from YouTube)

The Most Teeth in North America?

Sperm whale skeleton showing teeth (photo from Wikimedia Commons)

19 September 2022

Adult humans typically have 32 teeth after our wisdom teeth come in at age 12-14, but our count is low compared to other animals.

7-year-old smile with missing tooth (photo from Wikimedia Commons)

Which animal in North America has the most teeth?

The Virginia opossum (Didelphis virginiana) is a contender with 50 teeth in his small mouth. He shows them when he feels threatened.

Opossum showing teeth (photo from Wikimedia Commons)

Some say that sharks have the most teeth but as far as I can tell their tooth count, often lower than 100, is not as remarkable as their tooth replacement. For instance, young lemon sharks replace all their teeth every 7-8 days so that in their lifetimes “the lemon shark Negaprion brevirostris, may produce 20,000 teeth in its first 25 years, and may live as long as 50 years.

The winner of the most-teeth contest are land and sea snails which usually have between 10-15,000 teeth, though some may have up to 25,000. This includes snails in the ocean off the North American coasts.

Studies of the European garden snail (Cornu aspersum), an alien in North America, indicate it has 14,000 teeth. Take a look at his toothy mouth under a microscope and find out why snails have so many teeth at NMH.org: Microscopic look at snail jaws.

European garden snail (photo from Wikimedia Commons)

Amazingly, the most abundantly land snail found in Pennsylvania, Zonitoides arboreus, has no teeth at all!

Quick gloss snail, Zonitoides arboreus, Edgewater, Maryland (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Scallops on the Move

Atlantic bay scallop shell (photo from Wikimedia Commons)

7 August 2022

Scallops travel by opening and closing their shells but the direction they move seems counterintuitive. They don’t lead with their hinges. Instead the open edge goes first as they use their eyes to guide themselves.

Scallops’ eyes look like bright beads at the shells’ front edge.

Slightly open live Atlantic bay scallop; eyes look like bright beads (photo from Wikimedia Commons)

Watch scallops on the move in this Twitter movie.

(photos from Wikimedia Commons; click on the captions to see the originals)

Flat or Spiky, Always Toxic

Puffed up porcupinefish (photo from Wikimedia Commons)

11 July 2022

This spiky ball, a pufferfish, is so toxic that if eaten it can kill 30 adult humans.

There are more than 260 species of pufferfish in two families, almost all of which are toxic: Diodontidae and Tetraodontidae. The spiky ones are aptly called porcupinefish.

They don’t swim fast so their main defense is to blow up into an unappetizing ball. When fully extended their buoyancy changes and they involuntarily roll onto their backs, exposing their white bellies. In this position they can still swim with tiny fins.

How do pufferfish blow themselves up? Why are they toxic? Who eats them? This video explains it all.

And though they are spiky, they somehow they manage to look cute.

(photo from Wikimedia Commons; click on the captions to see the originals)

Lightning and Fish

Lighting strikes as the USS Abraham Lincoln transits the Strait of Malacca (photo from Wikimedia Commons)

6 July 2022

When a thunderstorm approaches at the beach or a swimming pool, the lifeguards tell everyone to get out of the water. Lightning often strikes water and anyone in it can be electrocuted.

Fish live in water so why don’t they die from lightning? The National Weather Service explains:

Before a lightning strike, a charge builds up along the water’s surface. When lightning strikes, most of electrical discharge occurs near the water’s surface. Most fish swim below the surface and are unaffected.

National Weather Service: Lightning and Fish

This NWS animation shows the positive charge building on the surface and the negatively charged lightning strike spreading horizontally. Fish swim below it all.

Humans swim on the water’s surface where lightning has its greatest effect. In addition, lightning is a hazard in open outdoor spaces like beaches.

West Beach Galveston, 1973 (photo from Wikimedia Commons)

Interestingly in the US, the most dangerous activity during lightning is fishing; beaches are second. We thought golf was the worst but it is far down on the list.

US lightning death statistics by activity, 2010-2021 (table from National Weather Service, Paducah, KY)

During a thunderstorm the fish are safer than the fisherman.

(photos and animations from Wikimedia Commons; click on the captions to see the originals)