Category Archives: Mammals

Preserving an Iconic Animal

Mammals, Musings & News
Scimitar-Horned Oryx, (Oryx dammah) in Marwell Zoo, Hampshire, UK (photo from Wikimedia Commons)

7 November 2022

The scimitar-horned oryx or scimitar oryx (Oryx dammah) is extinct in the wild but not extinct on Earth. These iconic animals still exist because their beauty prompted us to preserve them.

Scimitar-horned oryx are desert antelopes that can survive without water for months or years by absorbing water from the plants they eat. Native to the Sahel (pink on map below), there may have been 1 million of them at the height of their population in the early Holocene (9500–4500 BPE) but they declined over the centuries due to climate change and hunting.

Map of the Sahel from researchgate.net

However they were already iconic. Ancient Egyptians domesticated them, Ancient Romans bred them. They were prized for their horns and meat.

Scimitar oryx at Chester Zoo (photo from Wikimedia Commons)

Unfortunately the wild population of scimitar oryx dropped to less than 200 by the early 1980’s and within 10 years the last ever seen was in Chad. Declared extinct in the wild in 2000, they still existed in captivity.

Soon captive breeding programs looked for suitable locations in the Sahel for the antelope’s reintroduction and began breeding them in zoos and in herds to succeed in the wild. In the U.S., ranches in Texas breed them for reintroduction and for hunting.

To get an idea of what the animals look like, see this video from the Greater Vancouver Zoo.

Thanks to captive breeding, the first scimitar-horned oryx were released in Chad in 2016, as shown in this video.

Many endangered species go extinct before we know they exist. That didn’t happen to this iconic animal.

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

City Deer in the Rut

Deer, Mammals, Schenley Park
Doe drinks from a pond in Homewood Cemetery, Pittsburgh, 10 October 2022 (photo by John English)

25 October 2022

If you’ve been watching white-tailed deer (Odocoileus virginianus) in the City of Pittsburgh you’ve noticed that they’ve changed their behavior since early September. Back then deer were easy find in groups during the day but now in October they seem to have gone missing. Soon — very soon — they’ll be running into traffic. All of this is part of their breeding season, called the rut, which is driven by photoperiod.

In late summer, white-tailed deer hang out in bachelor groups of adult males and matriarchal groups of does with fawns. As the rut goes through phases, described below, the dynamics change. In the city we live with so many deer that it’s good to know the phases.

Pre-Rut Phase: In late September and early October testosterone levels rise in the bucks, they rub on trees and shed velvet from their antlers. The bachelor groups break up as each male goes it alone and adjusts his home range. During this phase the bucks eat a lot, especially acorns. Once the rut begins they’ll be too busy to eat while chasing, breeding and tending does.

Buck on a tree, Fall 2008 (photo by USFWS Mountain-Prairie via Flickr Creative Commons license)

The buck rubs were fresh in Schenley Park on 9 October 2022. Right after this the bucks “disappeared” from the park.

Buck rubs in Schenley Park, 9 October 2022 (photos by Kate St. John)

Bucks also spar to settle their pecking order as shown in this photo from Tennessee. I have never seen sparring in the city parks.

Two bucks locking antlers, Great Smoky Mountains, Tennessee (photo from Wikimedia Commons)

Seeking and Chasing Phase: As the females begin coming into estrous the males search for and chase does in heat. The bucks move around lot, averaging 3-6 miles per day. Meanwhile doe+fawn groups break up as adult females become distracted. Watch out! They may run into traffic.

The late summer groups have already broken up in Schenley and Frick Parks. The only deer I’ve seen recently are lone females or almost grownup fawns.

Peak of the Rut: According to The Whitetail Rut in Pennsylvania, the peak in Pennsylvania lasts about five weeks, 29 October to 3 December. Their graph, embedded below, is tiny on purpose so that you will look at the original graph, including date ranges, on the Boone & Crockett Club website.

Graph embedded from Boone & Crockett Club: “The Whitetail Rut in Pennsylvania”

At the peak of the rut bucks make long excursions out of their home range in search of females, sometimes 10-20 miles. The peak also includes a “tending” phase during which bucks and does pair up and hide in thick cover to breed repeatedly.

Post-Rut Phase: Activity drops off precipitously in early December after most of the does have bred. Adults stop wandering and settle into their home ranges. The males still have antlers and some will search for recently-matured fawns that come into estrous (red color in graph above), but the frantic edge is gone.

When will we see deer in lazy groups again in the city parks? Wait and see.

11+ deer in Schenley Park, Cathedral of Learning in distance, March 2019 (photo by Kate St John)

Resources for this article:

(photos by John English, Kate St. John and Creative Commons licenses from USFW Flickr and Wikimedia Commons. Embedded graph from Boone & Crockett Club website)

Busy as a Beaver

Mammals
Beaver gnawing a tree, Wilhelma Zoo (photo from Wikimedia Commons)

21 October 2022

No matter where they live beavers (Castor canadensis) must gnaw wood every day to wear down their constantly growing front teeth. In captivity they are given wood to keep their teeth healthy.

A beaver in rehab doesn’t have to make a dam but it’s obviously an instinct that’s hard to deny. He builds a dam at the doorway.

Busy as a beaver!

(photo from Wikimedia Commons, embedded video from YouTube)

Dolphins Shed Their Skin Every 2 Hours

Mammals, Water and Shore
Dolphin playing in the wake, Everglades (photo from Wikimedia Commons)

16 October 2022

Dolphins have specialized skin for their underwater lives. The outer layer (epidermis) feels rubbery and is 15 to 20 times thicker than our own. It stays smooth because:

Dolphin skin constantly flakes and peels as new skin cells replace old cells. A bottlenose dolphin’s outermost skin layer may be replaced every 2 hours. This sloughing rate is 9 times faster than in humans. This turnover rate ensures a smooth body surface and probably helps increase swimming efficiency by reducing drag (resistance to movement).

— Seaworld.org: Bottlenose dolphin characteristics

Dolphins will even take turns to rub their bodies on corals and sponges, an activity that probably feels good. (video: Why Taking Turns Is Good for Dolphin Skin)

We know these things about dolphins because some have a close association with humans. Veterinarians and trainers take an active interest in the welfare of animals in their care.

Dolphin looking above the water, Kyoto Aquarium (photo from Wikimedia Commons)

Dolphin veterinarians are especially concerned that as dolphins age, their heart health may suffer. This includes the dolphins in the U.S. Navy’s Marine Mammal Program in San Diego.

Photo from 2003: Dolphin wearing geolocator during mineclearance operations, US Navy Marine Mammal Program (photo from Wikimedia Commons)

Last year the Navy asked for proposals to place heart monitors on their aging dolphins to unobtrusively monitor them as they move about in the ocean. There are many challenges to doing so including the dolphins’ skin. Because the skin turns over every two hours nothing can stick to it for long. I wouldn’t know about their skin if I hadn’t heard about the heart monitors.

The vast majority of us rarely if ever seen dolphins in the wild and know very little about their lives. We are mesmerized when we see them this close.

Fascinated by dolphins, Dolphin Bay (photo from Wikimedia Commons)

It’s hard not to love them.

(photos from Wikimedia Commons and from Royal Society Publishing; click on the captions to see the originals)

October With Too Many Deer

Deer, Mammals, Plants & Fungi, Schenley Park
Colorful leaves, Schenley Park, 9 Oct 2022 (photo by Kate St. John)

10 October 2022

The season has changed and the woods in Schenley Park look different than they did a month ago. The trees are putting on fall color and deer are providing more evidence of their overpopulation in the park.

Doe browsing in Schenley Park, 21 Aug 2022. NOTE: A buck-rubbed sapling is in the foreground (photo by Kate St. John)

With the growing season over there is less greenery for deer to eat and there are fewer places to browse because they have already denuded many areas.

Nothing growing on the ground in the presence of too many deer, Schenley Park, 9 October 2022 (photo by Kate St. John)

What is left has been eaten down to nubs, just visible above the unpalatable invasive plants. Below, goutweed nearly hides the tops of what used to be jewelweed while pokeweed was browsed to tiny leaves and bare stems.

Favored plants are browsed to the tops of unappetizing plants (goutweed), Schenley Park 9 Oct 2022 (photo by Kate St. John)
Pokeweed overbrowsed by deer, Schenley Park, 9 October 2022 (photo by Kate St. John)

As the greenery disappears deer eat tree saplings and small branches. In cases of deer overpopulation, such as Schenley Park, the young trees are foraged down to bonsai.

Ash tree sapling overbrowsed by deer, like bonsai, Schenley Park, 9 Oct 2022 (photo by Kate St. John)

Schenley no longer has enough food for deer so at night they walk into neighborhoods and browse in backyards. This is happening across the city and has prompted some residents to consider a Deer Management Plan for Pittsburgh. KDKA’s Andy Sheen reports: Some Pittsburgh residents say it’s time to get deer population under control. Click on the link or the screenshot below.

Some Pittsburgh residents say it’s time to get the deer problem under control, KDKA Andy Sheehan

(photos by Kate St. John + screenshot from KDKA)

Six Ways of Looking at an Anteater

Mammals
Giant anteater swimming (photo from Wikimedia Commons)

7 October 2022

Giant anteaters (Myrmecophaga tridactyla) are related to sloths and are native to Central and South America. True to their name they eat ants and insects and their bodies are formed for that lifestyle, including a long snout and tongue and powerful claws for digging out insects.

Here are six ways of looking at an anteater.

Giant anteater foraging (photo from Wikimedia Commons)
Giant anteater emerges from tall grass (photo from Wikimedia Commons)
Giant anteater sticking out its tongue, Detroit Zoo (photo from Wikimedia Commons)
Giant anteater sleeping (photo from Wikimedia Commons)

Giant anteater mother carrying baby on her back

Learn more about giant anteaters at Wikipedia.

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

Who’s Herding Who?

Mammals
Border collie herding sheep (photo from Wikimedia Commons)

5 October 2022

Some dogs are bred to herd sheep and the instinct is so deep that they try to herd at every opportunity.

However, training helps. So does experience, as shown in this tweet from @SlenderSherbet.

(photo from Wikimedia Commons, embedded tweet from @SlenderSherbet)

When Will The Chipmunks Disappear?

Climate Change, Mammals
Eastern chipmunk (photo from Wikimedia Commons)

3 October 2022

The hardest thing to notice in Nature is the date of an absence. When did the last junco leave in the spring? When did the last groundhog go into hibernation?

Right now eastern chipmunks (Tamias striatus) are busy gathering nuts to store in their underground burrows for the winter. As the season changes and temperatures drop they will disappear into their burrows to enter torpor, sleeping off and on through the winter.

The warm winters of climate change can fool them into not entering torpor but the result is deadly. Only 10% survive. Find out why in this vintage blog:

Here Today, Asleep Tomorrow

Meanwhile I will hope our chipmunks disappear and will try to figure when they do it.

Here’s how I notice an absence: I write down every day when I do see them and then scan my notes for days when I’ve not logged them anymore.

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

Deer Are Picky Eaters

Deer, Mammals, Plants & Fungi
Arrowwood viburnum, Schenley Park, September 2019 (photo by Kate St. John)

29 September 2022

In western Pennsylvania, where we have a high deer population, gardeners have learned from experience that white-tailed deer will eat some plants and not others. They heavily browse their favorites to the point of killing them but leave others untouched, even plants in the same genus.

Viburnum is a case in point. Gardening advice at Rutgers University’s Landscape Plants Rated by Deer Resistance indicates that arrowwood viburnum (Viburnum dentatum) is deer resistant. Pictured at top, these shrubs are healthy in Schenley Park where the deer population is more than 100 per square mile.

Deer also don’t like the Japanese snowball (Viburnum plicatum) which thrives as an invasive in Frick Park, shown below.

Viburnum plicatum fruit, Schenley, July 2019 (photo by Kate St. John)

But they love our native hobblebush (Viburnum lantanoides) and consume it to local extinction.

Hobblebush (Viburnum lantanoides) is a favorite food of deer (photo taken in Maine by Kate St. John)

Read about hobblebush in this vintage article.

Extirpated From Pennsylvania?

When it comes to viburnum, deer are picky eaters.

(photos by Kate St. John)

The Most Teeth in North America?

Fish, Frogs, Mammals, Musings & News
Sperm whale skeleton showing teeth (photo from Wikimedia Commons)

19 September 2022

Adult humans typically have 32 teeth after our wisdom teeth come in at age 12-14, but our count is low compared to other animals.

7-year-old smile with missing tooth (photo from Wikimedia Commons)

Which animal in North America has the most teeth?

The Virginia opossum (Didelphis virginiana) is a contender with 50 teeth in his small mouth. He shows them when he feels threatened.

Opossum showing teeth (photo from Wikimedia Commons)

Some say that sharks have the most teeth but as far as I can tell their tooth count, often lower than 100, is not as remarkable as their tooth replacement. For instance, young lemon sharks replace all their teeth every 7-8 days so that in their lifetimes “the lemon shark Negaprion brevirostris, may produce 20,000 teeth in its first 25 years, and may live as long as 50 years.“

The winner of the most-teeth contest are land and sea snails which usually have between 10-15,000 teeth, though some may have up to 25,000. This includes snails in the ocean off the North American coasts.

Studies of the European garden snail (Cornu aspersum), an alien in North America, indicate it has 14,000 teeth. Take a look at his toothy mouth under a microscope and find out why snails have so many teeth at NMH.org: Microscopic look at snail jaws.

European garden snail (photo from Wikimedia Commons)

Amazingly, the most abundantly land snail found in Pennsylvania, Zonitoides arboreus, has no teeth at all!

Quick gloss snail, Zonitoides arboreus, Edgewater, Maryland (photo from Wikimedia Commons)

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