If you have ever approached a tiny spider that jumped suddenly far and fast you’ve probably seen a jumping spider (Salticidae), one of 6000 species on Earth.

Jumping spiders are harmless to humans and can be identified by the position of their eyes. They have four pairs(!) with the largest front and center. As for jumping, they use their back legs.

Jumping spiders’ well-developed internal hydraulic system extends their limbs by altering the pressure of their body fluid (hemolymph) within them. This enables the spiders to jump without having large muscular legs like a grasshopper. Most jumping spiders can jump several times the length of their bodies.

— Wikipedia: Jumping Spider

When not jumping I’ve seen them move in a jerky fashion.

Phidippus mystaceus jumping spider momentarily distracted by a passing velvet mite.#salticidae #trombidiidae #arachnida pic.twitter.com/8BQjgQls7E

— Thomas Shahan (@ThomasShahan) January 17, 2021

Like a furry robot.

(photo from Wikimedia Commons; click on the caption to see the original)

11 December 2020

One thing we don’t see in Pittsburgh are the antics of lizards. Only two lizard species occur in southwestern Pennsylvania but are rarely found, so when I saw Russ McSpadden’s tweet of two zebra-tailed lizards in the Sonoran Desert I was fascinated.

Their territorial sparring looks like cartoon dinosaurs.

Two adorable male zebra-tailed lizards engage in territorial street fighting deep in the Sonoran Desert.

?Organ Pipe Cactus National Monument pic.twitter.com/X16Z86QdOf

— Russ McSpadden (@PeccaryNotPig) December 4, 2020

So who are these guys?

Zebra-tailed lizards (Callisaurus draconoides) are 2.5 to 4 inches long, not including their tails, and are endemic to the open desert of the southwestern U.S. and northern Mexico.

During the breeding season, May to August, males are particularly colorful with iridescent blue and sometimes orange on their bellies. Each male defends a territory and works to attract multiple females. The more females he has the greater his social status and the more aggressively he defends his territory. Hence the threatening dance.

You can’t see much of the zebra tail in the video but these lizards use it as a social signal and predator deterrent. According to Wikipedia, “When threatened zebra-tailed lizards run quickly with their toes curled up and tails raised over their backs, exposing the stripes” as shown in the photo below.

The dominant lizard in the video must be shouting at the other guy, “Leave now! Run away! Show me your tail!”

(*) The two lizard species that occur in southwestern PA are the northern fence lizard and five-lined skink. I’ve never seen a five-line skink and have only seen a fence lizard once — in Virginia Beach.

(photos from Wikimedia Commons; click on the captions to see the originals. embedded tweet from Russ McSpadden @PeccaryNotPig)

In November, when the rains begin in southwest Madagascar, all the Labord’s chameleons (Furcifer labordi) hatch from eggs and begin their growth spurt to adulthood. They will live a glorious four to five months.

By January they are sexually mature, the males fight for dominance, they breed and the females lay eggs. (Male shown above. Females lack the snout “horn” and bony head casque.)

By the end of March, all of them die. Every one of them. All that’s left of Labord’s chameleons are their eggs, waiting eight months for the next rainy season.

There is no other terrestrial vertebrate with a shorter known active life-span.

— from Labord’s chameleon description at Wikimedia Commons

Our own lives are short, too, compared to Galapagos tortoises (190 years), Greenland sharks (300-500 years) and giant bristlecone pines (5,000 years).

Make every day count.

Thanks to Jason Bittel (@bittelmethis) for his tweet that brought Labord’s chameleon to my attention.

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

22 September 2020

Pretty soon it’ll be too cold for frogs but right now we still have a chance to see these two in Pennsylvania. Though similar it’s useful to know the difference because one is mildly poisonous.

Northern leopard frogs (Lithobates pipiens), at left above, are harmless and sometimes green. Don’t rely on their green color for identification though because some are plain brown. All four below are northern leopard frogs from the same place in Minnesota. Notice that the spots on their backs are irregular circles and somewhat scattered even on the brown one.

Pickerel frogs (Lithobates palustris) are mildly poisonous. When frightened they excrete a poison from their skin that’s toxic to predators and mildly irritating to human skin. To identify them, notice the chocolate brown blob-like rectangles arranged in two rows between the two folds on their backs (dorsolateral folds).

The Pickerel frogs can also be distinguished by the bright yellow or yellow-orange color on the inside concealed surface of the thigh. Leopard frogs are white in the same area. 

— BioKids article at Univ of Michigan

Here’s a live pickerel frog showing off his spots.

The Pickerel Frog shows off its striking pattern. If it’s cover gets blown, plan B is the poison that it packs in it’s skin. Mildly irritating to people, distasteful to predators, they are the only native poisonous frog in the USA. pic.twitter.com/GN2HdltcKc

— incidental naturalist (@IncNaturalist) September 15, 2020

He’s the one that’s poisonous.

p.s. A note on Poisonous versus Venomous:

• Poison is passive, just used as a defense. You have to ingest or touch a poisonous substance to be harmed by it.
• Venom is active, injected into you by the animal that carries it. It’s used as both offense to capture prey and defense.

(photos from Wikimedia Commons, click on the images to see the originals)

10 September 2020

Though 2020 has been an awful year it has a silver lining: Monarch butterflies are relatively plentiful. I saw my first monarch in late July. Now that they’re migrating to Mexico I see several every day.

How are they navigating to Mexico?

During their fall migration, Eastern North American monarch butterflies (Danaus plexippus) use a time-compensated sun compass to aid navigation to their overwintering grounds in central Mexico.

— Antennal circadian clocks in migratory monarch butterflies

The compasses are in their antennae! Combined with a circadian clock that figures out where the sun ought be at any time of day, the compass compensates for the sun’s position and keeps the monarch heading in a southwesterly direction.

Monarchs can navigate better than some of us!

On Throw Back Thursday, read more in this vintage article: The Sun Compass.

(photo by Steve Gosser)

p.s. The article was written seven years ago when the monarch population hit a dangerous record low. The population rebounded in 2018-2019 but it’s hard to know if they’re safe yet. This population graph from Journey North was not updated in spring 2020. I’ll bet COVID-19 interfered.