Category Archives: Mammals

Black Bears Take To Water

Black bear swimming, Quebec (photo from Wikimedia Commons)

You may remember this news on 23 December 2021: “Three days before Christmas a 260 pound black bear was trapped behind Boy Scout Headquarters in Downtown Pittsburgh where he’d been living for more than two weeks on a wooded hillside.”

How did a black bear end up in a city that’s nearly surrounded by rivers? Did he walk through the East End neighborhoods?

The clue comes from the bear’s first sighting in the Strip District, a neighborhood built on the Allegheny River floodplain. He probably came from the north and swam across the Allegheny.

According to the North American Bear Center in Ely, Minnesota black bears are “good swimmers though their speed and distance limits have not been tested. They can swim at least a mile and a half in fresh water. One bear swam more than 9 miles in the Gulf of Mexico.” (see Quick Black Bear Facts).

Since black bears operate at night to avoid us, we rarely see them swim but they can take to water like ducks when they want to travel or beat the heat. Here’s a black bear swimming in Canada.

During the heat of August 2015 a family of six bears splashed in a backyard pool in New Jersey.

The bears had fun but couldn’t help breaking things.

(photo from Wikimedia Commons, videos embedded from YouTube; click on the captions/videos to see the originals)

Footprints in the Snow

Allegheny National Forest at Beaver Meadows Recreation Area, 12 Jan 2022 (photo by Barb Griffith)

15 January 2022

The sun was shining and the temperature was in the mid 30s when six of us arrived at Beaver Meadows Recreation Area in the Allegheny National Forest on 12 Jan 2022. We were there to find 40 red crossbills (Loxia curvirostra) reported on 29 December. Just one perched in profile would be enough for me. I had to see the beak.

There were few birds in the forest but with an inch of snow on the ground we saw plenty of tracks including the small footprints of meadow voles or white-footed mice, the species that leave most of the little tracks in winter(*).

This one dragged his tail as he bounded across the path, planting his back feet in the prints of his front feet as he hurried from one subnivean hole to the next.

Likely the footprints of a white-footed mouse, Beaver Meadows, 12 Jan 2022 (photo by Kate St. John)

Since meadow voles have relatively short tails my guess is that the print was made by a white-footed mouse, (Peromyscus leucopus) pictured below. Notice the long tail.

We saw many other tracks including:

  • Fox on the lake ice
  • Otters slid on lake ice near their den. A local man helped us with this ID and showed us a photo of the otters.
  • Red squirrels made small highways between trees.
  • Bobcat,
  • Snowshoe hare.

This was my first ever look at snowshoe hare (Lepus americanus) tracks but I recognized the distinctive large hind feet that spread like “snowshoes” to help them walk on snow. (An optical illusion may make the footprints appear to bulge. My boot is at bottom of the photo for scale.)

Snowshoe hare track + tip of my boot, Beaver Meadow Recreation Area, Allegheny National Forest, 12 Jan 2022 (photo by Kate St. John)

Here are two sets of snowshoe hare prints, plain and marked up with notes. In the smaller track the hind feet are just less than 4″ long. In the larger the hind feet are about 6″ long.

Tracks of two snowshoe hares, Beaver Meadow Recreation Area, Allegheny National Forest, 12 Jan 2022 (photos by Kate St. John)
Tracks of two snowshoe hares, Beaver Meadow Recreation Area, Allegheny National Forest, 12 Jan 2022 (photos and markup by Kate St. John)

And here’s the mammal that makes these prints. Snowshoe hares are active at night, dusk and dawn so of course we didn’t see any.

Snowshoe hare in winter at Denali (photo from Wikimedia Commons)

Ultimately we saw 10 species of birds, only 26 individuals, five of which were red crossbills. It was worth the trip for the snowshoe hares. Yes I did see a crossbill beak.

(*) Information on tracks is from Track Finder by Dorcas Miller.

(photos by Kate St. John and from Wikimedia Commons; click on the captions to see the originals)

The Almost Christmas Downtown Dumpster Bear

O my! A real live bear was in Downtown Pittsburgh (photo from Wikimedia Commons)

23 December 2021

In Case You Missed It …

Three days before Christmas a 260 pound black bear was trapped behind Boy Scout Headquarters in Downtown Pittsburgh where he’d been living for more than two weeks on a wooded hillside. He would have gone unnoticed except for the huge mess he left at the dumpsters every night.

Flag Plaza snapshot from Google Street View

The Energy Innovation Center, next door to the Boy Scouts, set up a surveillance camera and caught him in the act.

Hands up! Stop raiding the dumpsters!

Game Warden Doug Berman of the PA Game Commission brought over the bear trap and the rest is history. Find out more in Mary Ann Thomas’ story at Trib Live: Black bear trapped in Downtown Pittsburgh Wednesday Morning and see her video tweets embedded below.

This is how close the bear was to Downtown Pittsburgh’s skyscrapers. I wonder if he’ll miss this view from the parking lot.

The view from Flag Plaza, March 2015 (photo by Kate St. John)

(Christmas bear from Wikimedia Commons, photo of Boy Scout Headquarters at Flag Plaza from Google Street View, view from the parking lot by Kate St. John, tweets embedded from Mary Ann Thomas; click on the captions to see the originals)

Maryland Zebras Are Back On The Farm

Zebras eating hay in Impala Game park Kisumu, Kenya (photo from Wikimedia Commons)

15 December 2021

After four months on the loose the wild zebras of Maryland are back on the farm from which they escaped in August. News of their return was announced on Tuesday 14 December 2021.

Spokesmen for the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service and the Prince George’s County Department of the Environment confirmed that the zebras have been captured, but they could not provide details on when the recovery took place.

Neither the USDA nor Prince George’s County Animal Services were involved in the capture. They said they were notified Monday that the zebras had been recovered and returned to their herd last week. 

Washington Post: Zebras in Maryland caught after months on the run, officials say

WUSA9 tells the story in this 14 December YouTube video.

Click here for WUSA9 video: Maryland zebra story

Read more at WUSA9 or the Washington Post.

p.s. On a happier note click here for a video about three well cared for zebras in Cecil County, Maryland including advice from their owner. (The Cecil County zebras live on the other side of Chesapeake Bay from the “wild zebras of Maryland.”)

(zebra photo from Wikimedia Commons, WUSA9 screenshot from YouTube video; click on the captions to see the originals)

Do They See What We See?

GG looks up from a meal (photo by Chad+Chris Saldin)

30 November 2021

We humans assume that what we see is what everyone else sees, including other species. But this isn’t so.

Peregrines see much finer details at a greater distance that we do. The details don’t blur for them in a 200 mph dive. (Click the link to learn more.)

Tellus in a stoop (photo by Chad+Chris Saldin)

Cats cannot see red-green nor distant details, but they see much better in the dark. Who needs distance vision while looking for a nearby mouse at night? Click here to see photos of our vision versus cats’. Notice the normal vs. red-green-color-blind examples below.

Domestic cat (photo from Wikimedia Commons)
Normal vision vs deuteranopia (red-green color blind) (images from Wikimedia Commons)

White-tailed deer see regular blaze orange as gray but if the orange has fluorescence it stands out for them. Their vision is best in the blue range so that they see well in twilight.

White-tailed deer at Schenley Park (photo by Kate St. John)
Non-fluorescent blaze orange looks gray to deer ( sign from PA Game Commission, Blaze Orange Vest on Amazon)

Birds see ultraviolet light though we cannot. Here’s how we know this and a hint at what birds look like in ultraviolet light.

Do other species see what we see?

No. Birds see more.

(peregrine photos by Chad+Chris Saladin, deer photo by Kate St. John, remaining photos from Wikimedia Commons)

Very Tiny Possums

Adult male honey possum, Tarsipes rostratus from Scott National Park in the southwest of Western Australia in torpor (photo by Don Bradshaw via researchgate.net)

The honey possum (Tarsipes rostratus), is a tiny species of marsupial that feeds on the nectar and pollen of a diverse range of flowering plants in southwest Australia.

Who is the other cute possum mentioned in the tweet above?

The little pygmy-possum (Cercartetus lepidus) is the world’s smallest possum, as small as a mouse and considered a threatened species in South Australia.

Government of South Australia

After the 2019 bushfires on Kangaroo Island, Australia, scientists feared the little pygmy possum was dead. Instead…

Definitely cute!

(honey possum photo from researchgate.net; tweets embedded from @LettsGetSnakes and @BBCWorld)

Why Do Zebras Have Stripes?

Zebra stripes (photo from Wikimedia Commons)

22 November 2021

While thinking of the wild zebras of Maryland, I wondered …

Why do zebras have stripes? There are many theories.

Are zebra stripes for camouflage from predators?

No. A 2016 study by Univ of Calgary and UC Davis examined the visual acuity of the zebras’ top predators, including lions and hyenas, and compared it to what zebras and humans can see.

Predators of zebras: spotted hyena and lion (photos from Wikimedia Commons)

The study found that beyond 50 meters (about 164 feet) in daylight or 30 meters (about 98 feet) at twilight, when most predators hunt, stripes can be seen by humans but are hard for zebra predators to distinguish. And on moonless nights, the stripes are particularly difficult for all species to distinguish beyond 9 meters (about 29 feet.) This suggests that the stripes don’t provide camouflage.

UC Davis: Zebra Stripes Not for Camouflage

In fact, to distant lions and hyenas, zebras look as plain as a wild ass.

Photos of three zebra species and African wild ass from PLOS ONE: Zebra stripes through the Eyes of Their Predators, Zebras and Humans

Are zebra stripes for identifying each other?

Each zebra has stripes as unique as our fingerprints. No two zebras are the same. We humans can visually identify individual zebras by their patterns (see below). However, the same 2016 study found that zebras don’t see their own stripes as well as we do.

Do zebras use the stripes for identity? Not exclusively.

Two zebras in the wild (photo from Wikimedia Commons)

Wikipedia explains that a new zebra mother imprints her own striping pattern, scent and vocalization on her foal so the youngster will recognize and follow her.

Are zebra stripes for cooling?

Maybe. A 2015 study at UCLA posited that the stark black-and-white stripes set up convention waves on the animals’ coats, making them cooler in the African sun. Wider stripes cool better than narrow ones. To support the theory, among the three species of zebras (shown above with wild ass) the widest striped live in the hottest part of Africa while the narrow-striped live in the cooler region.

This theory has not been tested, though.

Are zebra stripes for protection against biting flies?

Yes. This has been fully tested by biting flies, zebras, and horses wearing zebra coats.

A horse dressed as a zebra to investigate fly behavior in England (Credit: School of Biological Sciences/University of Bristol), embedded from NYTimes article quoted above

In a 2019 study — Benefits of zebra stripes: Behaviour of tabanid flies around zebras and horses — zebras and horses wearing zebra stripes were exposed to biting flies. The flies could not land on the stripes.

The zebra stripes seemed to dazzle the flies so much that they couldn’t manage a controlled landing. Flies zoomed in too fast and either veered off just in time — or simply bumped into the zebra and bounced off. The flies didn’t seem to like the zebra coats on horses, either, but their bare heads were fair game.

New York Times: Why Do Zebras Have Stripes? Scientists Camouflaged Horses to Find Out

Protection from flies is a big advantage for zebras because they have short, bite-able coats and “they are uniquely susceptible to the diseases carried by the flies.”

However, there is no simple answer.

“Really, the striping is kind of extraordinary, so you need something extraordinary to explain it.”

Why do zebras have stripes? It’s not for camouflage

There are many reasons for having stripes but only the zebras know for sure.

Zebras at Ngorongoro Crater, Tanzania (photo from Wikimedia Commons)

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

Zebra Update

These are NOT the Maryland zebras! (photo from Wikimedia Commons)

16 November 2021, Pittsburgh, PA

It’s hard to keep track of wild zebras in Maryland from 200 miles away, but I couldn’t help wondering if the two escapees are still roaming Prince George’s County. As of this morning, Google cannot find any news that the zebras have been captured — yes, it would have been big news — so it’s safe to assume they are still at large.

Even if you live near them it’s hard to keep track of the zebras. A lot has happened since they escaped in August.

For now two zebras are still in the “wild” in Maryland. Meanwhile I leave you with this historical note from @MarylandZebras:

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

COVID Deer

Deer approaches human in Markham ON, May 2020 (photo from Wikimedia Commons)

14 November 2021

In case you missed it.

At the beginning of the COVID-19 pandemic scientists wondered if other species could catch the virus and transmit it back to humans. Fortunately, so far no COVID-infected animals have transmitted the virus back to us. However white-tailed deer easily catch COVID from humans and spread it deer-to-deer.

NPR reports that a study of deer in Iowa last year found that deer are very susceptible to COVID. During most of the year 30% of tested deer had COVID, but during hunting season with more human contact 80% of deer showed signs of infection. Deer also spread it easily among themselves so that the prevalence of COVID in deer is now 50 times that of humans.

Deer are lucky. COVID doesn’t make them sick and it doesn’t kill them. But the fact that the virus that causes COVID, SARS-COV-2, circulates so widely among a common North American mammal may come back to bite us.

If deer become a reservoir for SARS-COV-2 and eventually transmit it back to us or to our livestock or companion animals (dogs and cats), then it has a good chance of mutating into something more unpleasant. At the very least it will never disappear.

The fact that deer catch COVID should not surprise us. SARS-COV-2 jumped from bats to humans and then spread easily from human-to-human. Here are some other viruses that cross species.

As deer have shown, virus jumping is more common than we thought.

Read more or listen to the podcast at NPR: How SARS-CoV-2 in American deer could alter the course of the global pandemic.

(photo from Wikimedia Commons)

The Wild Zebras of Maryland

Zebras sneezing, Lake Naivasha, Kenya, 2007 (photo by Eric Brelsford via Flickr Creative Commons license)

15 October 2021

The saga of Kodiak the Steller’s sea eagle who escaped from Pittsburgh’s National Aviary on 25 September ended when he was captured on 3 October. Not so for the wild zebras of Maryland. No one thought they would still be roaming in October and yet …

On 31 August, three (*not five) zebras escaped from an 80-acre farm off Duley Station Road in Upper Marlboro, Maryland. One was found dead in an illegal snare trap on 16 September. Now more than seven weeks later two are still on the loose in Prince George’s County. It’s not for lack of trying.

Zebras are genetically programmed to escape lions, hyenas and cheetahs so they’re naturally wary and very fast. They can’t be caught by chasing, they have to be corralled. Caretakers and Prince George’s County Animal Control have been trying to lure them into a pen. The zebras are having none of it.

At first there were many reports including this 7 September news story from NBC Washington. Click here to read the details. (Note: With six zebras in camera view, I believe this footage was taken above the farm.)

Plus this nighttime sighting reported by WUSA9.com on 24 September.

But the news is quieter now. The zebras have plenty of grass to eat and lots of places to go. They’re winter-hardy and can be out there indefinitely.

Despite every attempt to domesticate them, zebras are forever wild.

p.s. For weeks the media reported that 5 zebras had escaped but on 14 October the Washington Post reported it was only three. At first three traveled together, then one died and it was two. Three + two = five? Not in this case.

UPDATE on 18 October: The latest plan for capturing the two zebras is to use more zebras!

UPDATE on 16 November: The zebras are still on the loose but there’s lots of news.

(photo by Eric Brelsford via Flickr, embedded videos and tweet from NBC Washington, WUSA9. Check @MarylandZebras for updates)