Category Archives: Mammals

80% of the World’s Dogs Are Street Dogs

Village dog in Ecuador (photo by Kirk Johnson via Flickr Creative Commons license)

23 May 2023

An article about tracing the DNA of the famous sled dog Balto included this (paraphrased) fact about dogs:

Geneticist Kathleen Morrill compared Balto’s DNA with more than 600 genomes of wolves, coyotes, and dogs of different breeds including modern sled dog breeds such as Siberian huskies, more physically and genetically isolated sled dogs in Greenland, and “village dogs”— ownerless canines that live in Africa, South America, and Asia and make up 80% of the world’s dogs.

Science Magazine: Hidden details of world’s most famous sled dog revealed in massive genomics project

Being from a place where free-ranging dogs are rare because they’re collected by Animal Control, I was amazed to learn that more than three quarters of the dogs on Earth are “village” or “street” dogs.

I had a taste of this on my trip to Ecuador in February. I saw many, many free-ranging dogs in the cities, villages and the rural countryside.

Street dogs in Ecuador (photo by Zebo Serrano via Flickr Creative Commons license)

The dogs in Quito understood busy streets and the ebb and flow of traffic. They jaywalked when the street was clear to feast on the garbage bags placed on the median for collection. This was obviously a problem in rural places where people built raised platforms for their trash bags.

Not all of the dogs were on the street. I saw them perched on balconies …

Dog on a balcony, Ecuador (photo by Man Bartlett via Flickr Creative Commons license)

… and on roofs.

Dog on the roof, Ecuador (photo by F Deventhal via Flickr Creative Commons license)

At first I thought the street dogs were ownerless strays but then I noticed some had collars.

Veterinarian Nancy Kay visited Ecuador in 2016 and asked questions about the street dogs. She learned that most had owners but the owner-dog relationship is different than we’re used to in the States. Her insights include (paraphrased from her The Street Dogs of Ecuador blog):

  • “Much like ravens and crows, these street dogs always managed to get out of the way [of vehicles] just in the nick of time.
  • For the most part the dogs are owned solely for the purpose of property protection.
  • While the dogs go home at night, most of their daylight hours are spent out on the streets.
  • Most receive a modicum of food from their owners, so must rely on food found on the streets to sustain themselves.”

Learn more about the street dogs of Ecuador in veterinarian Nancy Kay’s blog: Speaking For Spot, The Street Dogs of Ecuador.

p.s. There are no ravens or crows in Ecuador. Perhaps dogs fill that niche.

(None of these photos are mine. Credits and links to the original photos are in the captions)

How Did I Get Here?

Squirrel outside my 6th floor window, 4 May 2023 (photo by Kate St. John)

8 May 2023

I live on the 6th floor of a high rise so I was startled to glance out the kitchen window last Thursday and see the back end of a squirrel. I know squirrels can climb but this one had to scale a brick wall, climbing more than 60 feet without the help of anything. No exterior fire escapes. No nearby trees. Nothing but bricks and window ledges.

The wall the squirrel had to climb, 5 May 2023 (photo by Kate St. John)

When I saw him on my windowsill he was looking in the direction of a bird feeder more than 100 feet away on the building next door. City squirrels walk wires to cross the street so maybe he thought he’d find a wire connecting the buildings. No such thing.

He contemplated his exit. “How did I get here? How do I get back?”

Squirrel contemplates getting down from here, 4 May 2023 (photo by Kate St. John)

He must have figured it out. He was gone the next time I looked.

p.s. Thank you to Chris Zurawsky for pointing out my Power of Ten problem. Indeed the squirrel was 60 feet up, not 600 feet as I originally wrote.

(photos by Kate St. John)

I Miss The Schenley Park Foxes

Fox kits in Schenley Park, 25 April 2020 (photo by Frank Izaguirre)

28 April 2023

Three years ago this week, five little foxes came out every day to play inside the fence surrounding their den under the Neill Log House in Schenley Park. At the end of April 2020 their antics were a bright spot in sixth week of the COVID shutdown and attracted a crowd.

Five little foxes attract a crowd in Schenley Park, 27 April 2020 (photo by Kate St. John)

After the fox family dispersed, Public Works cleaned up the log house basement and blocked access to the den. In the spring of 2021 the family denned in a rock outcrop below the Falloon Trail but that must have been too close to people and dogs. They haven’t been back since then.

When I saw this Twitter video by @urbanponds_101 I remembered the Schenley Park foxes.

Gosh, I miss them!

(photos by Frank Izaguirre and Kate St. John; Twitter embed from @urbanponds_101)

Armadillos Are On Their Way to Pennsylvania

Nine-banded armadillo, Santa Ana National Wildlife Refuge, Texas (photo from Wikimedia Commons)

2 April 2023

Here in Pennsylvania when we see a photo of an armadillo we immediately think “Texas,” but we could just as well think Tennessee. Nine-banded armadillos expanded across Tennessee in less than 50 years and by the end of this century, probably sooner, they’ll walk into Pennsylvania. Their current (2006) and future ranges are shown on the map below.

Current and predicted U.S. range of the nine-banded armadillo as of 2006 (map from Wikimedia Commons)

Northward expansion is nothing new for armadillos. Originally from South America, where there are still 20 species, armadillos are part of the Great American Interchange that began 6.7 million years ago when Panama’s land bridge joined North and South America.

The surprising thing about armadillos, though, is that their expansion in the U.S. is nearly ten times faster than the average rate expected for a mammal. How soon they get to Pennsylvania depends on the speed of climate change.

Armadillos have no fur so they are sensitive to cold weather but not all of it. Yale Climate Connections says, “Researchers now believe that armadillos can thrive as long as average minimum temperatures stay above about 17 degrees Fahrenheit.” Pittsburgh has 12 to 32 days each winter that drop below 17, which are probably too many for an armadillo.

But just wait. They’ll get here. This video explains how and why.

video from Backyard Ecolocy on YouTube

Read more about their range expansion at Yale Climate Connections. Learn about armadillos at “Armadillo Online!

(photos and map from Wikimedia Commons, video from Backyard Ecolocy on YouTube; click on the captions to see the originals)

More Deer, More Ticks, More Lyme

Deer in Schenley Park, Aug 2022 (photo by Kate St. John)

20 March 2023

Black-legged tick season is here again and with it comes the threat of Lyme disease. We now find ticks in neighborhoods where they never used to be and white-tailed deer are the reason why. More abundant deer mean more ticks. More abundant ticks mean more Lyme disease. Though deer themselves don’t spread Lyme disease they have an effect on its abundance. Let’s examine the Deer, Ticks, Lyme connection.

Lyme disease is a debilitating illness caused by a bacteria (Borrelia burgdorferi) that’s transmitted by the bite of a black-legged tick. 

Black-legged ticks (Ixodes scapularis and Ixodes pacificus) have a two year life cycle as egg, larva, nymph and adult. At each stage the tick must drink a blood meal to transition to the next one — from larva to nymph, from nymph to adult, and from adult female to produce eggs. (Note: Ticks eggs do not carry the Lyme bacteria.)

Chart of black-legged tick life stages (image from Wikimedia Commons)
Chart of black-legged tick life stages (image from Wikimedia Commons)

Larval ticks are so tiny that their normal blood hosts are small animals and birds including the white-footed mice, chipmunks, short-tailed shrews and masked shrews that are responsible for infecting 80-90% of ticks. Nymphs and adults are large enough that they can also feed on humans and deer.

Black-legged tick life cycle (diagram from CDC enhanced with life form names)

When a tick bites a host and sucks its blood it takes up the host’s blood and transfers some of its own body fluids into the host. If the host is infected with the bacteria, it infects the tick. If the tick is infected, it infects the host.

Deer cannot transmit Lyme to ticks because they’re never infected by it (lucky them!). Deer are not to blame for spreading Lyme. However deer are key to the black-legged ticks’ reproductive success.

Deer are the adult ticks’ preferred host and their long distance transport system. Deer bodies are the place where adult ticks meet and mate in the fall. After mating the male dies but the female lives on. She sips a last blood meal, then drops off to the ground and hides in leaf litter while her body develops eggs over the winter.

Adult ticks meet in the fall during the rut while deer are moving around a lot. Bucks average 3-6 miles per day but may travel as much as 10-20 miles in search of does. Does may travel to meet or evade them.

Deer in western Pennsylvania (photo by Steve Gosser)

Meanwhile ticks are along for the ride. When a pregnant female tick drops off after her last blood meal she may be 3 to 20 miles from where she started and she’s carrying 1,000 to 3,000 eggs that she’ll lay in the spring.

In places with overabundant deer moving into new areas, as is happening in Pennsylvania, we find an abundance of ticks where they’ve never been seen before. Pennsylvania also has the highest number of Lyme disease cases in the U.S.

Deer are not the reservoir for the Lyme disease bacteria but in places with too many deer there are too many ticks. More ticks mean more Lyme disease.

Deer cross the road in Schenley Park, July 2020 (photo by Kate St. John)

For more information check out these resources:

p.s. There’s also a flu-like disease, called babesiosis, that’s carried by black-legged ticks and is now gaining momentum. Uh oh!

Beavers on Video, Castor Up Close

Beaver swimming in Saskatoon, summer 2022 (photo from Mike’s Photos and Videos of Beavers)

5 March 2023

Since January I haven’t heard anything about the beaver in Frick Park but I’ve been watching beavers up close at Mike’s Photos and Videos of Beavers (@MDigout99).

Mike lives in Saskatoon, Canada where beavers (Castor canadensis) are more common than they are in Pittsburgh. Mike photographed seven at once last spring.

Seven beavers and one Canada goose in Saskatoon, spring 2022 (photo from Mike’s Photos and Videos of Beavers)

He’s able to get close for photos and videos because he’s patient, non-threatening, and willing to lie on his belly to get a good shot.

Twitter home of @MDigout99

His persistence pays off. Watch this beaver eat a tree (3 minutes).

He also documents their behavior. For instance, how long does it take a beaver to break into an unfastened tree fence? See below.

Check out his daily photos and videos at @MDigout99 on Twitter. Click here for his videos on YouTube.

(photos and videos from Mike’s Photos and Videos of Beavers, @MDigout99)

Orphaned Baby Stoats Grow Up

Short-tailed weasel or stoat (photo by NPS via Wikimedia Commons)

22 February 2023

Robert E. Fuller (@RobertEFuller) is a wildlife artist, filmmaker & blogger from Yorkshire, UK who uses bird cams to watch wildlife in his backyard. In addition to kestrel and owl nestcams, his live 24/7 cameras include the dens and habitats of stoats.

Stoats, also known as ermine or short-tailed weasels (Mustela erminea), have a circumpolar distribution that includes Alaska, Canada and Greenland but barely reaches Pennsylvania. In the UK they live in woodlands, grasslands, farms and heaths and are sometimes encountered during the day though they are generally nocturnal.

Fuller sees them frequently, especially on his wildlife cams. He says, “Over the years I seem to have become a stoat rehabilitator – as well as a wildlife artist. But that’s fine because I have a soft spot for these cute mustelids. Watch the story of my latest rescue, an adorable stoat called Rocket.”

His 11+ minute video shows Rocket and two other orphaned baby stoats growing up. They learn, play and explore together and then are soft-released into the wild.

See for Fuller’s art, blog and nestcams. Click here to go directly to his live nestcams.

(photo from Wikimedia Commons; click the caption to see the original. Video from Robert E. Fuller)

With Their Mind But No Wings

Coyote pouncing, Golden Gate National Recreation Area (photo from Wikimedia Commons)

27 January 2023

Coyotes (Canis latrans) are highly adaptable and very smart about food and humans because their lives depend upon it. Of course they live where food is plentiful but in places like Pennsylvania, where they’re hunted or trapped without limit all year long, they hide from humans and operate at night. In locations with less human pressure they forage during the day and encounter their familiars — ravens and sometimes crows.

Coyotes and Corvids often meet when it’s time to eat, especially at carcasses in winter. The carcass below attracted ravens and a black-billed magpie along with the coyote.

Coyote with ravens and magpie at a carcass in Wyoming’s National Elk Refuge (photo from Wikimedia Commons)

Ravens apparently realize that coyotes are smart for they sometimes enlist their help by leading them to a carcass they cannot open on their own.

Coyote near a raven at Metzger Farm Open Space, Colorado (photo from Wikimedia Commons)

How do Corvids describe a coyote? Perhaps like this, as described by Doug Anderson.


Hunch in the trees
to gossip
about God and his inexorable
about deer guts and fish so stupid
you could sell them air
and how out in the deserts
there’s a dog called coyote
with their mind
but no wings. …

— excerpt from Crows by Doug Anderson from Blues for Unemployed Secret Police Curbstone Press ©2000.  (Reprinted by permission, Click here for the full poem.

Common raven perched on a car (photo by David Kay from in 2011)

No wings? No problem. Here’s a coyote.

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

Humpback Whales Love Anchovies

Humpback whales lunge-feeding on anchovies in Monterey Bay (photo by Robin Agarwal via Flickr Creative Commons license)

25 January 2023

Every autumn humpback whales (Megaptera novaeangliae) migrate past California on their way to spend the winter off the coast of Mexico. They will linger, however, if they find lots of anchovies. Humpback whales love anchovies.

The California anchovy population typically rises and falls in 10 to 30 year cycles based on ocean conditions and fishing pressure. It surged in 2013 when the New York Times made this video (click on the image below) …

Screenshot from New York Times article... Click here or on the image to see the video

… and surged again this summer. In June 2022 there were so many anchovies that people reported small fish raining down from the sky in San Francisco, probably dropped by passing seabirds. In July anchovies were trapped in oxygen-poor water and died near shore, making a smelly mess.

There were still lots of anchovies when the whales showed up this fall. Robin Agarwal took a whale watch out of Monterey Bay in early October and captured these scenes of lunge-feeding humpback whales.

The anchovies crowded close as the predators approached. The whales forced them to the surface where the tiny fish leapt out of the water to escape.

Humpback Whales lunge-feeding on Northern Anchovies (photo by Robin Agarwal on Flickr)

The whales opened their mouths and anchovies fell in.

In a surge year for anchovies, people feast too.

Anchovies at Valley Bar + Bottle Shop, Sonoma, California (photo from Wikimedia Commons)

Read more about the 2013 anchovy surge in the New York Times: With Extra Anchovies and Whale Watching.

See more of Robin Gwen Agarwal’s photos here.

(humpback whale photos in Monterey Bay by Robin Gwen Agarwal on Flickr, Creative Commons license, food photo from Wikimedia Commons; click on the captions to see the originals)

If You Think Gray Squirrels Are Cute …

Gray squirrel (photo from Wikimedia Commons)

20 January 2023

Squirrels can be annoying at bird feeders but their expressions can be endearing.

If you think our eastern gray squirrels (Sciurus carolinensis) are cute you ought to see the native red squirrel of Europe (Sciurus vulgaris).

These native squirrels have been declining in the UK, Ireland, and Italy due to competition from eastern gray squirrels, imported from North America in the 1890s and spread by humans to new locations(*).

However, the native red squirrels are stabilizing in Scotland, in part because European pine martens (Martes martes) are increasing and they selectively prey on gray squirrels.

The European pine marten is pretty cute, too.

European pine marten (photo from Wikimedia Commons)

p.s. Gray (grey) squirrels are invasive in the UK but a 2016 study found that their populations are genetically distinct from their neighbors and they didn’t invade new places on their own. Humans spread them!

One of the worst offenders at spreading grey squirrels was the 11th Duke of Bedford, Herbrand Russell. Russell was involved in many successful animal conservation projects, but released and gifted many grey squirrels around the UK from his home at Woburn Park.

Russell also released populations [of grey squirrels] in Regent’s Park, likely creating the London epidemic of greys. 

Imperial College London: Don’t blame grey squirrels: their British invasion had much more to do with us

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