Category Archives: Mammals

There’s Never Just One Mouse

Emmalina looks at the source of the mousey sound, Nov 2011 (photo by Kate St. John)

On Throw Back Thursday:

Seven years ago when my cat alerted me to a mouse under the heat duct, I knew in my head that there’s never just one mouse.  But my heart refused to listen and I said to myself, “Of course there’s only one mouse, and when I catch that one I’m done.”

Hah!  Every fall I’m reminded that there are victories but in a 111 year old house you’re never done. Thankfully there are so few mice this fall that Emmalina has not noticed them.  Does this mean there are none or that she’s too old to care?

On Throw Back Thursday, here’s how naive I used to be about mice.  It started with Mouse in the House and followed up with The Observer Effect.

p.s. The photo at top is seven years hold. Here’s a recent one of Emmy, 12 years old now, playing with her treat ball.

Emmy plays with her treat ball, Nov 2018 (photo by Kate St. John)

(photos by Kate St. John)

Catnip For Cheetahs

Cheetah at Pittsburgh Zoo, 16 May 2018 (photo by Kate St. John)

When my husband and I visited the Pittsburgh Zoo last spring we stopped by the cheetah exhibit to watch these graceful cats and learn about them from the zoo’s cheetah experts.  We were amazed to find out that cheetahs like perfume. It keeps them from being bored.

Zookeepers have known for years that big cats, including lions and tigers, react to some perfumes the way housecats react to catnip.  They sniff and flemen and rub their faces on the scented spot.  My cat Emmy shows how it’s done with her catnip toy.

Emmy rubbing her face on a catnip toy (photo by Kate St. John)

Instead of catnip the big cats prefer perfume and they don’t like the expensive stuff.   Watch how perfume turns them on in this National Geographic video.

Apparently Calvin Klein’s Obsession for Men is catnip for cheetahs.

(photos by Kate St. John; video by National Geographic on YouTube)

Elk Putting On A Show

Sparring bull elk in Elk County, PA (photo by Paul Staniszewski)

The elk are putting on a show in northcentral Pennsylvania right now and they don’t care if we watch.

Elk or wapiti (Cervus canadensis) are one of the largest members of the deer family.  Males weigh up to half a ton(!) and can be five feet tall at the shoulder with antlers five feet across.  The females, without antlers, are only 3/4 their size. The difference is due to their lifestyle.

From late August through mid-October the elk herd assembles for the mating season, called “the rut.”  The males sound off and fight to win females for their harems.  Bigger is better. The strongest males have the most offspring. 

Their bugling and sparring is fascinating to watch and you can get fairly close because the herd is distracted.  Paul Staniszewski photographed these two locking antlers.

And here’s a 6-minute video shot in Benezette, home of Pennsylvania’s largest elk herd.

Visit Elk County, PA to watch the show. Click here for more information.

p.s. Wapiti were reintroduced in Pennsylvania in 1913 after we extirpated them in the late 1800s. Did you know white-tailed deer were reintroduced to Pennsylvania, too? 

(photos by Paul Staniszewski)

Schenley Park Outing: September 30, 8:30a

Chipmunk (photo by Cris Hamilton)

At the end of September the weather’s fine and there’s plenty to see outdoors.  Goldenrod and asters are blooming but everything else has gone to seed, fruit, and nuts.  This is great news for chipmunks.

Join me for a bird and nature walk in Schenley Park on Sunday, September 30, 8:30a – 10:30a.

Meet at Bartlett Shelter on Bartlett Street near Panther Hollow Road. We’ll see birds, fall flowers, fruits, seeds, acorns and busy chipmunks.

Dress for the weather and wear comfortable walking shoes. Bring binoculars and field guides if you have them.

Before you come, visit my Events page in case of changes or cancellations.

Hope to see you there!

(photo by Cris Hamilton)

Ooops! It Fell

Spray of white oak leaves found on the ground, Sept 2018 (Kate St. John)

In September I often find sprays of oak leaves littering the woodland trails. I used to think they fell in windstorms but I’ve discovered a more common reason. In autumn it’s squirrels at work.

Gray squirrel (photo by Chiswick Chap via Wikimedia Commons)

Gray squirrels build leaf nests high in the trees for shelter in winter, nests for their young, and for sleeping at night.  The outer layer is composed of leaves and twigs that make a water resistant blob about the size of a beach ball. The inside is lined with moss, grass, shredded bark and other soft vegetation. The entrance faces the trunk. 

Squirrel nests can be as much as 70 feet off the ground. Here’s what one looks like. 

Gray squirrel nest (photo by Marcy Cunkelman)
Gray squirrel nest (photo by Marcy Cunkelman)

To gather building materials, the squirrel gnaws near the branch tip — often an oak — until the spray of leaves comes loose.  If he isn’t careful to hold the twig, it falls. Oh well. The squirrel gnaws another one.  

You can tell when a spray of leaves is a squirrel’s handiwork.  The tip of the twig looks chiseled. Teeth made this mark!

Tip of a white oak twig chiseled by a squirrel (photo by Kate St. John)

Last week I found many leafy twigs on the trails in Pittsburgh.  After four days of cold rain the squirrels were making nest repairs.

As winter approaches you’ll find them, too. The squirrels are fortifying their nests and they don’t have much time. The leaves will be gone in November.

(photos by Kate St. John, Marcy Cunkelman and from Wikimedia Commons; caption has a link to the original)

Not Dead, Just Resting

Virginia opossums (Didelphis virginiana) walk with a bumbling gait and have poor eyesight and hearing so when they finally notice danger it’s very close at hand.  They’ve evolved a pretty good solution to protect themselves.  Possums fall over and play dead.

Playing dead is triggered by extreme fear and it’s involuntary — like fainting.  The possum enters a near coma, lying on its side with its mouth and eyes open and tongue hanging out.  Meanwhile it exudes a putrid green fluid from its anus that’s unappetizing to predators.

The possum in this video was probably shocked when the big black dog showed up. Boom! He fell over.

But how to remove him?

Wait and he’ll wake up and walk away. Put the dog indoors and he’ll do it sooner.

He’s not dead. He’s just resting.

Oh, The Opossum!

Virginia Opossum (photo by Chuck Tague)
Virginia Opossum (photo by Chuck Tague)

My blog about rabies prompted a comment from Joyce Peronne about the Virginia opossum (Didelphis virginiana).

Did you know that possums are resistant to rabies, though not immune?

On Throw Back Thursday, click the links to read more amazing facts about this underappreciated mammal.

Oh, the opossum!


(photo by Chuck Tague)

Lawn Chemicals Linked To Dog Cancer

Dogs ready to play (photo from Wikimedia Commons)
Dogs ready to play (photo from Wikimedia Commons)

This news is so old that I’m amazed I didn’t learn it until last month.

Weed killers save time but researchers have known for decades that their use is linked to cancer in dogs.

Spraying a dandelion with weed killer (photo from Wikimedia Commons)
Spraying a dandelion with weed killer (photo from Wikimedia Commons)

2,4-D is a widely used weed killer that’s been around since the 1940s.  It kills broadleaf weeds by causing uncontrolled growth in them, sort of like cancer in weeds.

Why study dog cancer?

Of course we love our dogs and want to know about their illnesses, but there’s an additional reason to study dog cancer.  Canine malignant lymphoma (CML) is so similar to non-Hodgkins lymphoma (NHL) in humans that CML is used as a model for NHL.

Linking lawn chemicals to dog cancer:

  • A 2012 study showed a 70% higher risk of dog cancer (CML) in households that used professionally applied lawn chemicals. Fortunately, they found that flea and tick controls are unrelated to the risk of CML.  Click here for the study.
  • And a 2013 study found an increased risk of bladder cancer in dogs exposed to professionally applied lawn chemicals. Click here for the study.

There’s a growing body of evidence that lawn chemicals — especially 2,4-D — are bad for humans.  I didn’t realize that for 27 years we’ve known they’re bad for dogs.


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

p.s. In July 2017 California added glyphosate (the active ingredient in Roundup) to their list of potentially cancerous chemicals.

What About Rabies?

Raccoon and skunk (photos from Wikimedia Commons)
Raccoon and skunk (photos from Wikimedia Commons)

When I wrote about skunks last Friday, I said that “skunks carry rabies” but revised the text when Nathalie Picard pointed out that “carry” is misleading.  Today I’ll explore the subject of rabies, who is at risk, and why the word carry is used for this disease.

Rabies is a virus that causes inflammation of the brain and death in mammals.  Its pathway to humans is by a bite or scratch from an infected animal.  When the virus first enters a human there are typically no symptoms for one to three months, though that period can range from 4 days to several years. During the asymptomatic period the victim feels fine.

When symptoms finally appear rabies has reached the fatal stage and the victim will die in 2-10 days. The only cure is a preventive vaccine (PEP) which must be administered within a few days of the original bite, long before symptoms appear.  (Read more here.)

Dogs are the main hosts and transmitters of rabies. Worldwide more than 17,000 humans die of rabies every year, 99% of them from dog bites.  95% of the deaths occur in Asia and Africa where dog rabies is poorly controlled and the post-exposure vaccine is unavailable.  More than a third of the deaths occur in India. (quoted from World Health Organization)

Thirsty dog in India (photo from Wikimedia Commons)
Thirsty dog in India (photo from Wikimedia Commons)

In the U.S. 92% of rabies comes from wildlife — bats, raccoons, skunks and foxes — called “rabies vector species” because they are at high risk for catching the disease.  Since post-exposure prophylaxis (PEP) is readily available here, only 2 or 3 people die of rabies per year.

Bats are the main cause of rabies death in the U.S. because people either do not realize they were bitten by a bat while sleeping/drunk/disabled or they do not seek treatment.  Those who handle wildlife are vaccinated against rabies in advance.

Biologist holds a little brown bat (photo by USFWS/Ann Froschauer via Wikimedia Commons)
Biologist holds a little brown bat (photo by USFWS/Ann Froschauer via Wikimedia Commons)

Here’s a graph of the CDC’s rabies statistics by species in the U.S. in 2015.  All mammals can catch rabies. The low percentage species are lumped in the “All Other” category.

Rabies Reports by Species in U.S., 2015 (graph created from data at
Rabies Reports by Species in U.S., 2015 (graph created from data at

Aside from bats, raccoons are the main rabies vector in the eastern U.S. while skunks are the main vector elsewhere.  Foxes are also a vector in Arizona, New Mexico and Alaska.  (See CDC map here)

And finally … Why is the word “carry” used about rabies?
Wikipedia defines a disease carrier as a person or organism who’s infected by a disease but displays no symptoms.  Since rabies has no symptoms at first, those with early stage rabies can be described as carrying it.   High risk species are “vectors” not carriers. They don’t carry rabies until they catch it.

The bottom line is this:  Avoid approaching wildlife, especially rabies vector species. Most of them are fine but you never know.  If you are bitten or scratched, don’t wait to visit the doctor.


(photos from Wikimedia Commons; click on the images to see the original.  In the composite photo at top: raccoon by D. Gordon E. Robertson and skunk by K. Theule/ USFWS)