Archive for the 'Mammals' Category

Jan 19 2016

Caracara, Capybara

Published by under Beyond Bounds,Mammals

Yellow-headed caracara on capybara (photo from Wikimedia Commons)

Yellow-headed caracara on capybara (photo from Wikimedia Commons)

Hawk on pig?  Well, almost…

Caracara on capybara.

The bird is a yellow-headed caracara (Milvago chimachima), a member of the falcon family native to South America(*) and similar in size to a Cooper’s hawk.

The mammal is a capybara (Hydrochoeris hydrochaeris), the world’s largest rodent. Its scientific name is Greek for “water pig.”  Its English name means “eats slender leaves” in the extinct Tupi language of Brazil.

Semi-aquatic, vegetarian, and closely related to the guinea pig, capybaras swim a lot.  They eat grass and aquatic plants which fortunately wear down their continuously growing teeth.  They also eat their own feces to get more nutrition out of their partially digested food.

Capybaras are big.  They stand as tall as a German shepherd but of course they’re not the same shape and they weigh a lot more.  For a sense of scale, here’s a group of capybaras grazing in a park in Brazil.

Capybaras grazing at Parque Barigüi, Curitiba, Brazil (photo from Wikimedia Commons)

Capybaras grazing at Parque Barigüi, Curitiba, Brazil (photo from Wikimedia Commons)

These groups are typical.  Capybaras are very social and live with 10-20 and up to 100 other individuals.  The round bump on their snouts is a scent gland called a morillo which they rub on everything to say “I’m here.”  They also use anal scent glands and urine for the same purpose.  Obviously capybaras do not make good pets.

As for the bird, why is the caracara on the capybara?

More on that tomorrow.


(photos from Wikimedia Commons. Click on the images to see the originals.)

(*) Both the bird and the mammal have increased their range into southern Central America.

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Jan 08 2016

Natural Born Hustlers: PBS NATURE

Are humans the only species that fools others to survive, find food, and mate?  Not at all!

This month PBS NATURE premieres a new three-part series, Natural Born Hustlers, airing on PBS on Wednesdays, January 13, 20 and 27 at 8:00pm (ET) (check local listings).

Episode One, Staying Alive, focuses on survival techniques:  camouflage, dominance tricks, audio mimics and playing dead.  Early on I was amazed to learn how zebras’ stripes create an optical illusion.  You have to see them in motion to believe it!

Other fascinating finds are the amazing skin-morphing camouflage of cuttlefish, the lizard that walks like a stinky beetle, and the white-faced capuchin monkeys who calculate whether they’re needed in battle.  “More capuchins are killed by their own kind than by predators,” says the episode.  What an unfortunate trait to have in common with humans.

The video excerpt above gives you a good idea of animals’ ingenuity.  California ground squirrels use their enemy’s scent as protective camouflage.  Their arch enemy is the rattlesnake, so if you hate to look at snakes this video will make you flinch.

And fair warning to those afraid of snakes:  Staying Alive has quite a few snakes in it including a match-up in North Carolina of a harmless species that mimics the coral snake.  The bonus is that you can identify birds by song on the audio track.


(Natural Born Hustlers trailer from PBS NATURE)

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Dec 28 2015

In The Beavers’ County

Chopped! Raccoon Creek State Park, Dec 2015 (photo by Kate St. John)

Chopped! at the Wetlands Trail, Raccoon Creek State Park, Dec 2015 (photo by Kate St. John)

This month I hiked the Wetlands Trail at Raccoon Creek State Park in Beaver County where I found many small trees chopped down next to Traverse Creek lake.  Across the water, cut treetops and shrubs lay in a messy half-submerged brush pile against the opposite shore.

The stumps don’t show the straight-edge cut of human activity.  If you look closely you see tooth marks.  Big incisors were at work.


The remains of a stand of alders, Raccoon Creek State Park, Dec 2015 (photo by Kate St. John)

The remains of alders, Raccoon Creek State Park, Dec 2015 (photo by Kate St. John)

Beavers (Castor canadensis) are obviously here now, but that wasn’t always the case.

When Beaver County was named for the Beaver River in 1800, their namesake was already hard to find.  The North American beaver population was 100 to 400 million before Europeans arrived to trap them but 300 years of over-hunting took its toll.  According to the PA Game Commission, “the last few beavers known to naturally exist in Pennsylvania were killed in Elk, Cameron, and Centre counties between 1850 and 1865.”

Game laws and reintroduction programs have brought beavers back to 10% of their former population. Today there are 10 to 15 million beavers in North America.

In Pennsylvania one indication of the beavers’ success is the number of complaints they generate, mostly about flooding including plugged culverts and flooded roads.  A lot of complaints often means there are a lot of beavers.

Where were the most complaints in 2008 in southwestern Pennsylvania?

In Beaver County.


(photos by Kate St. John)

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Dec 14 2015

Another Alien Invader

Published by under Mammals

Little brown bat with white nose syndrome (photo by USFW via Wikimedia Commons)

Little brown bat with white nose syndrome (photo by USFW via Wikimedia Commons)

Here’s news that surprised me about white nose syndrome, the disease that’s wiping out bat populations in eastern North America.

White nose syndrome (WNS) is caused by a cold-loving fungus, Pseudogymnoascus destructans, that thrives in temperatures 40-200 C (390– 680 F), which happens to be the winter temperature in caves where bats hibernate.

The fungus attaches to the bat’s exposed skin — nose, wings, ears — where it looks like white powder.  It doesn’t kill bats directly. Instead it eats away at their skin, causing irritation, dehydration, and higher metabolism that burns up their fat stores.(*)  The bats rouse themselves and fly around on mid-winter days looking for food.  There aren’t any flying insects to eat so they starve and die. Millions of them.

Since white nose syndrome first appeared nine years ago near Albany, NY the toll has been devastating.  The fungus has spread rapidly from state to state and into Canada, ultimately reducing some bat populations by 95%.  It was confirmed in western Pennsylvania in the winter of 2010-2011 and this year in Oklahoma.  There’s a real possibility that the little brown bat will go extinct in the next 15 years.

Bat researchers are now in a race against time to stop the fungus.  Meanwhile they found out where it came from: Europe.

How did it get here?

In The Sixth Extinction: An Unnatural History Elizabeth Kolbert describes its probable path as told by NY DEC’s Al Hicks.  The first record — in 2006 — was photographed in “a cave connected to Howes Cave, a popular tourist destination which offers, among other attractions, flashlight tours and underground boat trips.  “It’s kind of interesting that the first record we have of this is photographs from a commercial cave in New York that gets about two hundred thousand visits a year,” Hicks told me.”

And so it’s likely that someone with spores on their clothing or gear got on a plane in Europe and visited a cave near Albany.

It’s amazingly easy to introduce an alien invader.


(photo by U.S. Fish and Wildlife via Wikimedia Commons. Click on the image to see the original)

p.s. I highly recommend The Sixth Extinction: An Unnatural History by Elizabeth Kolbert.  It’s a great book, full of detective stories like this one.

(*) Click here for an article that answers the question: How Does White Nose Syndrome Kill Bats? Thanks to Deb Grove for the link.

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Dec 10 2015

The Acorn Plot

Published by under Mammals,Musings & News

Gray squirrel (photo by Chuck Tague)

Gray squirrel (photo by Chuck Tague)

On Throw Back Thursday:

Acorn abundance varies every year.  Some years there are lots of acorns, other years not so many.  This variation is an oak survival mechanism that alternately floods and dries up the market to insure that some of their nuts survive hungry predation by squirrels, turkeys and deer.

Back in December 2008 there were so few acorns in the Washington, D.C. area that the situation made national news and people put out store-bought delicacies for squirrels.

Were the squirrels begging for attention? Click here to read this 2008 article: The Acorn Plot.


p.s. Pennsylvania’s squirrels have nothing to worry about this winter and next. The PA Game Commission says the acorn crop will be abundant this year and in 2016. Click here to read more.

(photo by Chuck Tague)

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Nov 06 2015

What Happens At A Clearcut?

Tree removal project at Central Catholic, 30 Oct 2015 (photo by Kate St. John)

Before I retired from WQED in September 2014, this was the view outside my window … except there were trees.

Last month contractors removed all the trees on the hillside between CMU’s new Tepper Quad and Central Catholic’s football field.  By the time I saw it a week ago it looked like this.

Hillside denuded by tree removal project at Central Catholic, 30 Oct 2015 (photo by Kate St. John)

To give you an idea of what it used to look like, here’s a view of the remaining trees behind WQED.

Trees remaining on hillside behind WQED, 30 Oct 2015 (photo by Kate St. John)

In the grand scheme of things this was a small woodlot surrounded by parking lots and an astroturf field, host to many invasive species.

Does it matter that humans removed this small landscape?

It does to the animals who lived there.

In the remaining woodlot behind WQED two squirrels fought a territorial battle. The loud one said, “This is mine! You have to leave!” The other cowered but stayed nearby. Probably a refugee.

Winter or a predator will determine who survives.


(photos by Kate St. John)

p.s. Does anyone know whose project this is (CMU or Central Catholic?) and why it was done?

UPDATE:  I haven’t been back to the site for a week but friends confirm that this is a CMU project and that all the trees are gone now.  Every single one.

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Nov 04 2015

Teens Drink More In Crowds

Published by under Mammals

The mouse who gets (roaring) drunk C57BL/6 (image from The Jackson Laboratory linked from

Duh!  “Teens drink more in crowds” is not earth-shattering news.  The news is that these teenage mice drink more in crowds, too.

The discovery was made while looking for something else.

In 2013 psychologists Laurence Steinberg and Jason Chein of Temple University asked the question, “Does verbal peer pressure make teens drink more, or is it actions and not words that prompt them to do it?”  Since it’s impossible to run a controlled non-verbal test on drinking humans, they looked for a critter that voluntarily drinks alcohol.

Enter Mouse C57BL/6, otherwise known as Black-6, the most studied mouse on earth.  He’s an inbred lab mouse known for obesity, alcohol consumption, morphine addiction, a weakened immune system, pain sensitivity, atherosclerosis and age-related hearing loss.  And he can’t use verbal peer pressure. “We chose mice for this experiment, said Steinberg, “because mice don’t know what their friends want them to do.”

Science Daily explains what happened,

For the study, a sample of mice were raised in same-sex triads and were tested for alcohol consumption either as juveniles or as adults, with half in each age group tested alone and half tested with their agemates. The researchers found that the presence of “peers” increased alcohol consumption only among adolescent mice.

They published their findings two years ago in Developmental Science as: Adolescent mice, unlike adults, consume more alcohol in the presence of peers than alone.  I learned about it when I read Elizabeth Kolbert’s August article in The New Yorker:  The Terrible Teens.

The mice had a good time and no one got hurt.  Fortunately mice can’t drink and drive.


(photo linked from the article From Mice To Men at, where it was posted courtesy of The Jackson Laboratory. Click on the image to see the original article at Science Node)

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Oct 23 2015

Here Today, Asleep Tomorrow

Published by under Mammals

A chipmunk looks out from his burrow (photo by Chuck Tague)

A chipmunk looks out from his burrow (photo by Chuck Tague)

Every autumn I miss the moment when the chipmunks disappear.

For weeks they’re vocal and active while they gather food to store in their underground burrows for the winter.  Then one day they stay underground and go to sleep.  Days or weeks later it dawns on me, “I haven’t seen a chipmunk in a while.”

Chipmunks (Tamias (Tamias) striatus) are not true hibernators. Instead they go into periodic bouts of torpor in which they lower their body temperature and sleep deeply, then wake up to eat and defecate. On warm winter days we see them out foraging.

Ironically an unusually warm winter is fatal to chipmunks.  A study by Craig Frank at Fordham University found that chipmunks are less likely to enter torpor when the weather’s warm.  Those who do enter torpor have an 90% winter survival rate.  If they stay awake in warm weather, they die.  (90% mortality. Yow! Climate change is bad for chipmunks. Click here to read more.)

Some day soon the chipmunks will go underground, enter torpor, and not resurface until a warm winter day.  Will we notice their absence?

Here today, asleep tomorrow.


(photo by Chuck Tague)

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Oct 06 2015

Food For The Extinct

The "monkey ball" fruit of the Osage Orange tree (photo from Architect of the Capitol via Wikimedia Commons)

The “monkey ball” fruit of the Osage Orange tree (photo from Architect of the Capitol via Wikimedia Commons)

Why is the Osage orange (Maclura pomifera) “monkey ball” such a prolific fruit when almost nothing eats it?

Why is the avocado seed so large?  (Persea americana)

Open avocado showing huge seed (photo from Wikimedia Commons)

Open avocado showing huge seed (photo from Wikimedia Commons)


Why does the honey locust (Gleditsia triacanthos) have huge thorns on its trunk?  And…

Honeylocust thorns (photo from Wikimedia Commons)

Honeylocust thorns (photo from Wikimedia Commons)

… large seed pods that no one eats?

Honey locust seed pod (photo from Wikimedia Commons)

Honey locust seed pod (photo by Andrew Dunn from Wikimedia Commons)

These fruits are food for giants that are now extinct.

Just 13,000 years ago the Americas were inhabited by mammoths, horses and giant ground sloths whose diet included “monkey balls,” avocados and honey locust pods.  Only a giant could eat such large fruit in one gulp and pass the seeds through its digestive track.

The giant ground sloth (Megatherium) for instance weighed 4 tons (8,000 pounds) and could reach 20 feet up when he put his paw on a tree trunk and stood on his hind legs.  He could also damage the trees so the honey locust evolved big thorns for protection.

Megatherium, extinct ground sloth (illustration from Wikimedia Commons)

Megatherium, extinct ground sloth (illustration from Wikimedia Commons)

He’s been extinct for 10,000 years, but the tree remembers.


For a fun 5-minute video about the fruits that point to missing mammals, watch below.



(photos from Wikimedia Commons. Click on each image to see its original)

Notes and links:

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Sep 23 2015

Tock Tock Tock

Published by under Mammals

Here’s a hollow sound you often hear in the woods but you rarely see who’s making it.

Tock Tock Tock Tock, the sound travels and is echoed by additional singers.  Who’s making this sound and what does it mean?

The knocking is a chipmunk warning call that means “Danger From The Air!”  One chipmunk has seen an aerial predator and has frozen in position to warn everyone they’d better watch out.  The other chipmunks freeze, too, and echo the call until it’s impossible to tell where the warning began.

The video below shows the sound as we usually encounter it — a disembodied knocking.  In this case it’s louder than thunder.


If I’d known the sound’s meaning I would have looked for a raptor during my walk in the woods.


(videos by Mark Czerniec and MyBackyardBirding on YouTube)

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