Carnegie Museum of Natural History

One of the Four Carnegie Museums of Pittsburgh

Patrick McShea

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Blending Dark and Light

leatherback sea turtle light undersideleatherback sea turtle dark shell
by Pat McShea
A cast of a large leatherback sea turtle now swims overhead near the microscope station in
Discovery Basecamp. In its suspended position, this reptile model provides a clear example of the principle known as counter shading.

The term refers to a common animal color pattern in which the top (dorsal side) is dark while
the underside (ventral side) is light.

While swimming or resting in the ocean the turtle’s counter shading helps to camouflage it
from both the prey it seeks and the predators it must avoid.

Viewed from below during the day, the creature’s light colored underside blends with light
saturated water. Viewed from above, its dark back offers little contrast with murky waters beneath it.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Stream Sentences

Pennsylvania Stream
Photo courtesy of the Western Pennsylvania Conservancy

By Patrick McShea

Among the joys of working as a museum educator are times when the traditional learning flow reverses. A memorable example occurred a few years ago during a writing exercise for high school students participating in the Allegheny College Creek Connections program.

Each student had been studying a stream near their school. My task was to motivate them to share their findings and impressions through writing.

I asked participants to write the name of their stream in the sentence: “________ ________ is far older than the road that shares its valley.” Then they had three minutes to compose the next narrative line.

A Butler County student had less work time than her peers, owing to the fifteen-letter Indian name “Connoquenessing” for the creek waters bordering her school’s campus.

Still, when she later recited a sentence that beautifully referenced horse-drawn wagons and steam locomotives
to note differences in travel time between creek valley towns during the previous two centuries, I involuntarily said aloud, “I wish I wrote that sentence.”

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

 

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Color Returns

Wood Duck
By Patrick McShea

Within the Hall of Botany, a male wood duck’s beautiful plumage shares splendor with the fall foliage of a quaking bog in northwestern Pennsylvania.

At this time of year, as wood ducks begin to appear in wooded creek mouths along Pittsburgh’s rivers, bare branch canopies of sycamore and cottonwood trees offer little color competition.

The places where neighborhood streams surrender their flow to southwestern Pennsylvania’s big water are among the least accessible stretches of riverfront, so this early spring spectacle passes unnoticed by all but the most ardent river watchers.

Binoculars and a stealthy approach are both necessary to get a good look at these beautiful but wary birds. Because the banks of the Allegheny, Monongahela, and Ohio consistently document the variety of floatable
debris generated by our throwaway culture, river edge views of wood ducks are often aesthetically marred by the inclusion of tires, mud-stained blocks of Styrofoam, empty beer cans, and all kinds of plastic containers.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum. 

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Fast Cat and Invisible Insects

cheetah chasing gazelles in a diorama
by Patrick McShea

An argument can be made that one of the more interesting features within this diorama are the reddish earthen mounds framing the scene.

These irregular soil towers are termite mounds, the product of coordinated efforts by thousands of tiny social insects to create safe and stable living conditions. Mound-building termites are the master architects of the animal world. If they and their shelters were magically changed to our size and scale, their mounds would stretch upward as high as a 180 story building!

Within the thick walls of a termite mound air circulates through a network of channels to both cool the structure on hot days and warm it on cool days.

From hidden positions below ground and within their distinctive towers, termites exert tremendous influence over the landscape. By physically mixing various soils and their own wastes during the mound’s construction and as part of structure’s maintenance, the colony’s thousands of tiny insects improve the fertility of the savannah.

Herbivores such as the Grant’s gazelles featured in this diorama are attracted to the richer plant growth on the resulting islands of fertility. Cheetahs and other carnivores follow the plant eaters.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.

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Black and Gold Advantage

Hooded Warbler
by Patrick McShea

Recently, when a middle school science teacher borrowed a set of taxidermy mounts to stimulate class discussions about natural selection, I included a tiny bird clad in Steelers’ colors.

An account written by a museum curator more than 75 years ago provided a clear explanation for the advantage black and gold feathers provide to Hooded Warblers.

Once I was amazed to find myself eye to eye, as it were, with an adult male of this species. The bird was sitting quietly on a low branch of a leafy maple and must have flown in while my attention was directed elsewhere. Brilliant sun shining through the young leaves made some of them appear as yellow as the bird’s breast, while the green tones of its back were matched by other leaves in the shadow. The black markings of the head and throat were, in this instance at least, true “ruptive markings,” since it was some moments before I could clearly see the outline of the bird, although it was in plain view and in good light.

When examining specimens in the laboratory, it is difficult to think of the Hooded Warbler as protectively colored. I suspect the truth is that at some time and under some circumstances every bird or animal is seen with difficulty, both by man and by its natural predators. It is the nature of things that if the sum total of these occasions gives a species even an infintesimal advantage, the combinations of color that contribute to that survival-value will become genetically fixed.

W.E. Clyde Todd – Birds of Western Pennsylvania – University of Pittsburgh Press 1940

 

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences of working at the museum.

 

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Blue Fleece Jacket

Hikers in the forest
by Patrick McShea

Call it simple digital entertainment.

While checking the Tumblr blog of Carnegie Museum of Natural History for pictures and progress reports from the remote mountains of Peru, (Discoverers Expedition Vilcabamba 2016), I’ve been paying close attention to the garments worn by the field crew.

Weeks ago, when José Padial let fellow museum employees know about his team’s need for clothing that could provide insulation under ponchos, Amy Henrici and I assembled a bag of various fleece and wool items.

Today, in one of Maira Duarte’s beautiful photos, I spotted an old friend. The aqua blue fleece jacket that had once kept me warm on many miles of cross-country skiing in the Laurel Highlands was providing a similar benefit to an expedition member in very different terrain on another continent.

Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences of working at the museum.