Tag Archives: science

Bunny Blankets

8 Apr

A bunny in bear’s clothing? Yes, it is. A team of researchers in China developed a fabric that mimics the fur coat of a polar bear. A live rabbit was wrapped in a ‘blanket’ made img_6854-1of this prototype fabric and used infrared imaging (thermal imaging camera) to measure the difference between the rabbit’s body and ambient temperatures. The body of the rabbit under the blanket was almost completely undetected. Where the body was exposed to the changing temperatures (14-104 degrees Fahrenheit), thermal imaging detected only those exposed areas. This demonstrates good thermal insulation.

Like the fur of polar bears, the fabric also reflects infrared light. The blanket fabric reflected light up to twice that of commercial textiles and can’t be detected by night-vision scopes and cameras, just like polar bears.

What makes polar bear’s fur so special? A fiber from the fur of a polar bear is a


Polar bear fiberS

simple cylinder. The interior core of the fibers are hollow, which helps traps their body heat and insulate them from Arctic winters. This hollow trait of the bear’s fibers also reflect back infrared light, but the transparency of those same fibers scatter UV light to neighboring hairs, via light scattering. Their black skin absorbs and stores heat from that UV light. All these factors help insulate the polar bear from cold, even when wet. Think of passive solar energy and storage.
Despite being so porous, the fibers are strong because a thick layer of keratin surrounds the hollow core. Keratin is a protein common in nails and hair. Keratin protein molecules form a helix, and two keratin helixes wind around each other conferring both strength and elasticity. You can think of animal fiber as a thick rope containing many stings of these entwined keratin filaments. In the case of the polar bear, these keratin layers surround the hallow core.

So how did those scientists mimic the fur of a polar bear? They did so through a very complex process of spinning a mixture of compounds found in silk and crustaceans (like shrimp and crabs). A solution of fibroid, a protein in silk, and chitosan, a structural carbohydrate made from chitin, was spun in freezing conditions. Ice particles separated the fibers leaving air spaces when warmed. These resulting fibers, which had both properties of thermal insulation and strength, were aligned and then woven into a fabric, and tested on the bunny.

Being a fiber artist, I wondered how fibers from sheep compare to the properties of polar bear fibers. The variability of fiber between breeds and individual sheep is immense. So many factors influence the characteristics of wool fibers: breed, age, nutrition, and weather. However, the primary composition of wool fibers is fairly consistent.

Because I raised sheep in Oregon (decades ago) and spun their wool, I was familiar with the overall structure – overlapping scales in varying lengths – of wool fibers. However, I wanted more details on its morphological structure. I can quickly draw and label the structure of muscle fibers and fibrils, but not a wool fiber! So I searched online for a diagram and electron micrographs, longitudinal and cross-sectional,  of a typical wool fiber. From these we can see how polar bear fibers are structurally different, but they both have insulating properties.


Mammal, silk, and plant fibers

Most animal fibers contain exterior scales (except polar bears,  remember). You can see the difference in scales, or lack of, in the image to the right, in both animal, silk and plant fibers. Also apparent are the sizes of the scales, and their distance apart. These are the images most of us are familiar with when we think of fiber structure. But it’s more complex than this.

If we compare the fibers in this image to that of the polar bear fiber, we can see that fiber structure of wool is more complex. You don’t see slightly rough exteriors and hollow centers! Instead, wool has irregular and overlapping scales. But that’s not where the differences end.

Let’s look at the interior morphological structure of wool. Wool fiber contains three


Morphological structure of a wool fiber.

primary parts: the outer cuticle, the cortex (divided into two sections), and the medulla. The cuticle includes the scales and several layers that surround and protect the cortex.

The cortex is the bulk of a fiber. In that cortex are many macro- and microfibrils, similar to a muscle fiber. A similarity to the polar bear fiber, and that of most mammals, is keratin. The medulla is not really distinct, depending on the mammal species. It is empty space and arranged in a honeycomb fashion within the cortex. That space can be tiny, as in sheep breeds with fine fiber, or larger, which is more typical in medium and coarse fiber breeds.

The structure of the wool fibers, and the fiber ‘community’ (meaning the collective grouping of fibers in what we sheep folks call ‘fleece’), contribute to the insulating properties. Another structural component is fiber crimp. Wool fiber can be long and straight, or short with many crimps. The number of crimps, how they are spaced along the length of the fiber, and how close they are to neighboring fibers, greatly influence how much air a fleece can hold within it. That air also contributes to its insulating properties.

But it doesn’t stop there! At least for humans that shear those fleeces, wash and prepare them to spin into yarn that is eventually knitted or woven into fabric to wear or for other domestic purposes. The natural structure and characteristics of those fibers determine how we process the fleeces, how we spin them, use the yarn for a final product.

We could even knit a blanket for a bunny.

Loons and innate responses

25 Apr

In the Chihuahuan desert, no one would expect to hear what might be the most eerie sound of the watery forests, a bird more commonly known throughout the northern portions of the US. Especially a water bird. Yet I did, in disbelief.

I heard it the other morning, but I discounted it. ‘No way!,’ I thought. But I heard it again this morning. I know that wail like the blood that runs in my veins and my ears. It stirs deep inside like a wolf howl.

My childhood and most of my adulthood was spent in the northern regions in this country: Maine, New York, and Oregon. I know this sound, I know this bird. It is ingrained in my being like the beating of my heart.

Conversely, the common loon is very rare here in these parts of the desert. Water is scarce, and loons are an aquatic bird. The only documented reports of loons in this area are 1937 and 1988 (in Santa Elena Canyon on the Rio del Norte). Both were spotted on the Rio del Norte in the National Park. Another report of a loon spotting was in Boquillas Canyon a couple years ago.

It is amazing how (and even that it does) our ‘lizard brain’ responds to certain sounds. People usually don’t question man-made sounds, or sounds of a predator. They are typically associated with danger, pleasure, risk, etc, which is a plausible explanation. But a bird call that has no threat, instead eliciting a profound feeling of inate and inexplicable comfort and alliance is almost always casually dismissed by the scientific community.

There is one that could offer an explanation, neuroscientist V.S. Ramachandran*, who researches synesthesia and mirror neurons. He is one of the few scientists that ‘thinks outside the box.’ If the smell of rain is almost universally associated with the color green, and with pleasure, is it not possible that a bird call can elicit a profound psychological response other than fear?

At one point long ago, as a conventionally trained scientist I would have dismissed all this. Until a wonderful professor in my graduate biochemistry class impressed upon me once that we must  at some point in our lives accept that sometimes there is no explanation for what we ‘know’. And ‘knowing’ is a dynamic process. It’s a journey, not a destination. For a chemist to tell me that, it altered they way I understand things. And it enhanced my life both as an individual and as a scientist in so many ways.

The loon call literally gives me goosebumps and, simultaneously, a surge of endorphins. It stirs inexplicable primitive feelings in which no words can explain. All I can do is close my eyes and become a part of the sound, the bird and it’s environment.

It’s a ‘Zen’ thing.

A sampling of the sounds for the common loon can be found at this link to the webpage provided by Cornell Lab of Ornithology (All About Birds website).

* V.S. Ramachandran is Director of the Center for Brain and Cognition and Distinguished and Professor with the Psychology Department and Neurosciences Program at the University of California, San Diego. He is also Adjunct Professor of Biology at the Salk Institute. I highly recommend reading his book, Phantoms in the Brain: Probing the Mysteries of the Human Mind and listening to his many podcasts on iTunes and elsewhere. He’s also a fantastic speaker with a great sense of humor.

A wandering verbena (Desert Verbena)

19 Apr
Glandularia bipinnatifida. Photo courtesy of Pam Gordon.

Glandularia bipinnatifida. Photo courtesy of Pam Gordon.

Folks driving along the desert roads this month may see many small tight masses of purple flowers waving in the breeze. The Desert verbena are at their peak of flowering right now.

Here’s another example of ‘mixed identity’. There are many common names for this plant: Desert verbena, Prairie verbena, Dakota vervain, Davis Mountain mock vervain, and Moradilla. While many common names exist for a particular plant, one can usually rely on a more specific scientific name. Not the case here (again).

Older published widlflower guides list this plant as Verbena wrightii, and a member of the Verbenaceae (or Vervain) family. While our plant of the week is indeed in the Vervain family it’s genus and species names have changed.

Glandularia bipinnatifida close up.

Glandularia bipinnatifida close up.

Back in the early 1800’s, naturalist Asa Gray named the plant for Charles Wright , a teacher, surveyor, and plant collector, known notably with the Mexican Boundary Survey. However, new molecular research tools in the last decade or so have determined that a few members of the Vervain family have different chromosomes (numbers and sequences) in their chloroplasts, the organelles in plants that are the powerhouse for producing energy (photosynthesis).

Scientists discovered that some genetic information has been transferred between members of the Vervain and Glandularia genus. In other words, members of these two genus and species have hybridized not just once, but possibly three times as these plants spread north from South America.

Although several plants were once classified as Verbena, and still resemble many of that genus, they have been reclassified (1979) based on genetic similarities and differences. The most commonly known reclassified member is that which was known as Verbena wrightii, or Desert Verbena. It is now recognized in the botanical literature and more recent wildlfower guides as Glandularia bipinnatifida. Although there are two subspecies of this plant referenced (G. bipinnatifida var. cilia. and G. bipinnatifida var. bipinnatifida), their taxonomic classifications remain invalidated and both will find them used synonymously for this species. Perhaps more chemical and molecular studies will elucidate any differences that may exist.

Meanwhile, if you get close enough and smell these plants you may or may not be enamored of their fragrance. While many members of the Vervain family and Verbena genus have pleasant scents, this one had to sit outside after I gathered some samples yesterday. 🙂

For those interested in a recent review of the latter issue, see the following reference, “Taxonomy of the GLANDULARIA BIPINNATIFIDA group (Verbemaceae) in the USA”, by Guy Nesum (of Forth Worth!) in Phytoneuron, issue 46, 2010.

Jaguarundi eludes us in many ways

13 Apr

A mysterious small and elusive wild cat

A small wild cat, not much larger than the average house cat, the jaguarundi eludes us humans in many ways. Unbeknownst to this wild creature, our species can’t seem to decide who and what it really is. So we have created many names for the animal, changing its label depending on place and time. All the while, the jaguarundi smiles and eludes us. 

This member of the feline family is one of the smallest and oddest looking. The size of a large house cat, it has the face of a miniature cougar (aka puma, panther, mountain lion) topped with little rounded nice-kitty ears. Its slender long body (22-31″) and tail (14-24″) is supported by short legs (stands at ~11″ at the shoulder). Indeed, the mammal resembles an odd hybridized version of a house cat and dwarfed cougar whose ear and leg development was arrested within a  week after birth. In fact, the species has many times been mistaken for a large weasel. One wonders what circumstances selected for such odd paired combinations. Unless the other cats are the odd ones. 

The jaguarundi is a New World cat, native to forested and brushy regions, especially those near water, from South America to the southwestern United States. Rare north of Mexico, it is considered endangered in Texas, although sightings have been documented in SW Texas, Alabama and part of Florida. It is also known as the ‘otter-cat’ because of its otter-like appearance and swimming ability. In fact, early German zoologists mistook the animal for a cousin of the weasel, referring to it as the ‘weasel cat’.

The name jaguarundi is interesting for several reasons. Many people recognize the root name, jaguar, which is one of the largest New World members of the feline family. This cat once roamed from the  U.S.-Mexican border southward to Patagonia, Argentina. It is now almost extinct in the northern part of its original range and survives in reduced numbers in remote areas of Central and South America. Similar to the jaguarundi, the largest known population exists in the Amazon rainforest.

The names jaguarundi and jaguar have similar origins. Not surprisingly, because the two species inhabit the same region in South America. Before the arrival of the Portuguese to Brazil in the mid-1500’s, the two principal indigenous groups were the Tupí and the Guaraní. The former mainly lived along the coast of Brazil and in the Amazon rainforest. The Guaraní lived further inland, inhabiting what is now Paraguay, southern Brazil, and parts of Uraguay, Bolivia and Argentina. The Tupi-Guaraní language is the most widely distributed traditional language of South America and is a hybrid of the older Guaraní and Old Tupí. In fact, it is the official language of Paraguay.

A fusion of the languages of the Spanish-speaking conquerors of South and Central America and of the indigenous peoples has given rise to an interesting evolutionary tree of name etymology. Many names of flora and fauna are often attributed to Spanish origin. However, the earlier conquerors merely adopted and adapted native names to their own language to try and make sense of them, and probably because they were easier to pronounce. For example,  words like jaguar, tapioca, jacaranda, anhinga, carioca, and capoeira are of Tupí–Guaraní origin. An exploration of plant name origins will commonly end up with root words of the Tupí and/or Guarní language.

The first known use of the name jaguar was 1604. It probably originated with the Portuguese and was derived from from Old Tupí, jawára. Similarly, jaguarundi is American Spanish, first used in 1885, and derived from from Old Guarani yaguarund-i and akin to the Tupi jawarund or Old Tupi, yawaum’di. The jaguarundi is commonly known in Spanish as leoncillo, gato colorado, gato moro, león brenero, onza, and yaguarundí. It is also called gato-mourisco, eirá, gato-preto, and maracajá-preto in Portuguese.

jaguarundiThe jaguarundi wears coats of several colors, and several scientific names. With two color morphs, dark (black and brownish gray) and light (reddish brown), they were thought to be two different species. Local villagers often refer to these cats based on their color: “jaguarundi” for the darker coat and “eyra” for the reddish coat. (The Tupi name was eirara or irara; ‘eyra’ is an American Spanish and Portuguese name.) Thus early taxonomists separated them, assigning Felis eyra (1814) or Herpailurus eyra (1858) to the reddish morphs. However, these are the same species and both color morphs may be found in the same litter.

Likewise, the taxonomical nomenclature assigned to this wildcat have gone through several renditions, some concurrently. Various authorities have placed the jaguarundi in their own genus (Herpailurus) or with the other cats (Felis). A French naturalist, Étienne Geoffroy Saint-Hilaire (1772-1844), assigned the small cat the genus and species names Puma yagouaroundi in 1803. A follower of Lamarckian evolutionary theory, Saint-Hilaire’s assignment was based on comparative anatomy, paleontology, and embryology.

Use of Felis yagouaroundi has been attributed to two different authorities. However, the earliest attribution was given to Bernard Germain de Lacépède (1756-1825), a French naturalist, in 1809. Attributes to assigning the jauguarundi to the genus Herpailurus vary from Lacépède (again, 1809) to Nikolai Severtzov (1827-1885), a Russian explorer and naturalist (attributed to year 1858). Which of these men originally used this genus name might be lost to historical confusion, but this genus was still in use in 1919. Why Lacépède would use two genus names concurrently is beyond me.

Sometimes things come full circle, even if it takes a few centuries. Depending on the source of reference and information, anyone searching for the scientific name of the jaguarundi will  see all three genus names in use today. Interestingly, modern nomenclature again placed in the genus Puma by Johnson et al. (in 2006) and Eizirik et al. (in 2008). Recent genetic studies (mitochondrial DNA analysis) suggests that the puma (aka the cougar/mountain lion) and the jaguarundi are more closely related to each other and other felines in the genus Puma than the domestic cat, which shared the genus Felis. Additional research shows that the jaguarundi is closely related to the much larger and heavier cougar as evident by its similar genetic structure and chromosome count.

For those interested in the paleobiology of the New World felines, according to the 2006 genomic study of Felidae an ancestor(s) of today’s leopard, lynx, puma, and Felis lineages migrated across the Bering land bridge into the Americas approximately 8-8.5 million years ago. It is proposed that those lineages subsequently diverged in that order. This and other recent studies have indicated that the cougar and jaguarundi are next most closely related to the modern cheetah of Africa and western Asia, but that relationship is still debated. It has been suggested that ancestors of the cheetah diverged from the Puma lineage in the Americas and migrated back to Asia and Africa, while other research suggests the cheetah diverged in the Old World itself. Consequently, feline migration to the Americas remains unclear.

So, what’s in a Name? Well, that is the subject for another post. As readers can infer, names can be very complex and more confusing than not. Regardless, the jaguarundi, or the leoncillo – the little lion- remains elusive in name and reality. Perhaps that is best for it’s survival.

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