Hiding in Plain Sight

If you are lucky enough to live near a body of water such as a pond or a wetland you, like me, are  experiencing the chorus of spring peepers and maybe even wood frogs. Over the past two weeks the male frogs of both species have returned to their native pools or ponds and are calling enthusiastically in their attempt to attract a mate. My evening backyard walks usually include a game of “stalking” the calling frogs where, head-lamp installed, we play a game of hide and seek. In most cases the frogs win but it is still a worthwhile game for me. Using the frogs’ vocalizations I can often zoom in relatively accurately. Every once in a while if all the stars align into their proper position I am able to obtain some excellent photographs.

Wood Frog (Rana sylvatica) adults range from 1.5 to 2.5" in size and are usually only associated with water during the spring breeding season.

It is quite amazing how these little critters can find a way to hide right in plain sight. That said, recently I read a New York Post article by Lisa Foderaro about  the discovery a new frog species. Now you are saying yeah, they are finding new species all of the time in the rain forests. Why is this news? Well, what was really interesting about this find was that it was not in a remote area of South America, Australia or even Madagascar. It was on Staten Island! Yeah that’s right, they found a new species in New York City! The frog is a heretofore unknown species of leopard frog which physically looks very similar to the Southern leopard frog. Its only known identifier other than genetics, at this time, is that its call is a single “cluck” rather than the Southern frog’s repetitive “chuckle.” Listen to it here. Since the original discovery three years ago the new leopard frog species has been found south to Trenton, N.J, north to Putnam County, N.Y and in some areas of central Connecticut. Not a large geographic area but still not one small localized wetland either. The moral of this story is that  even though we see we may not be “seeing.”

New York Times Photograph by Brian Curry of New Species of Leopard Frog found in New York State

What is exceptionally troubling, however, is that although we are still just beginning to learn about and investigate much of the natural world around us, our discoveries cannot keep pace with the alarming rate of biodiversity loss and species extinction due to our mindless greed and need to tame and reengineer everything around us. As a result, over one-third of the greater than 6,000 species of amphibians in the world are currently threatened with extinction. And the amphibians are by no means alone. This is very sad from an ecological perspective but it also of concern for sociological reasons.

For a wide range of diseases, many of our most promising avenues of medical research have been found as a result of our study of animals or plants with unique physiological traits or adaptions. The loss of habitat and the species that live within threatens the discovery of many new medical treatments. Just to name a few are a new generation of antibiotics, treatments for a variety of cancers, thin bone disease, mascular degeneration (leading cause of blindness),  kidney disease, end-stage renal disease, Type I and II diabetes and obesity.

One rare fish known as the zebra fish found, among other places, in Lake Victoria has the ability to regenerate damaged heart tissue at an amazing rate. Most recently, a drug has been isolated from the fish that suppresses the growth of human prostate cancer cells and it has also been effective in the lowering of cholesterol.

Rare zebra fish photo, Daily Nation U.K. by Stella Cherono and Gatonye Gathura

Another example that did not have a happy ending involved gastric brooding frogs found only in the undisturbed rain forests of Australia in the 1980’s. This frog had the unique adaption for raising the young frogs in the female’s stomach where, in a normal world, the baby frogs would be digested by enzymes and stomach acid. Preliminary research revealed that the baby frogs produced a substance that inhibited acid and enzyme secretions while the young were present. Unfortunately the rain forests were cut down and the frogs perished before protection could be established and the research could be continued. In a recent United Nations Environment Programe (UNEP) book on the impact of species extinction entitled “Sustaining Life,” Harvard Medical School researchers and the book authors suggested that research on these frogs likely could have led to new insights to treat peptic ulcers and other stomach-related illnesses that effect 25 million people in the U.S. alone.

Obviously, not all resources are created equal, but in most instances we don’t know which ones are key to medical research until it’s too late. Some species are considered higher value candidates than others though. They include snails, non-human primates, sharks, amphibians, bears, gymnosperm plants and horseshoe crabs. Also, don’t forget the venomous shrew from one of my previous blog posts and its potential connection for the treatment for high blood pressure. Not that I personally condone animal testing, because I certainly don’t, but science is continually improving its ability to humanely extract the materials necessary for much of this research.

If clean air, water, healthy children, and a balanced sustainable environment are not enough motivation to control greed, reconsider unsustainable use of our natural resources, or curb endless sprawl and impervious development then maybe, just maybe, the “carrot” will be the promise of a longer life.

That said, now that amphibian breeding is in full swing if you have an inkling to learn  more about these wonderful critters or the world they live in I invite you to join me and some of my fellow Conservation Commissioners (that is if you live in or near the Town of Chelmsford, MA) to come visit some of our local vernal pool breeding areas and see them for yourself. If not find one near you and get out and enjoy the unique gifts that mother nature has to offer.

Vernal Pool site walk in Chelmsford MA, Saturday March 24 10 am at 105 Mill Road - Russell Mill Town Forest. Meet in the rear parking lot by the Soccer Fields. Hope to see you there!

Voles, Moles and Shrews, Oh what shall I do!

At least we can say the March came in like a lion… However, I am still finding it very hard to believe that the worst of our New England winter is over. I know what you are going to say, “What winter?” In my lifetime I cannot remember having this little snow and such warm sunny days. The lack of snow this winter, however, has definitely put a crimp in my winter tracking activities. It has also provided a little bit more of a challenge, and well, challenge can be fun! That said I am looking forward to some winter tracking this weekend!

A wintery day on Beaver Brook Meadow

A couple of weeks ago I went on a “varmint” hunt. Given the lack of snow and some spring “melt,” if you can call it that, I figured I had a fairly good chance of finding sign of some ground-burrowing critters. I started by looking under hanging garden plants and turning over boards or other fixed objects in our back yard. Bingo!

What did I find?   Shrews!   Shrews have been called a lot of things but I think that Sudbury Valley Trustees described them best as “tiny tigers.” They have sharp, spike-like teeth and as the smallest mammal no bigger than our thumb (2 to 4 inches), these creatures spend most of their time running around in above-surface tunnels hunting a variety of bugs and earthworms. They will also eat other shrews, mice, salamanders, snakes and have even been known to kill small rabbits! They may also eat mast, seeds or eggs. Shrews will even cover their “kill” with grass or leaves for a later meal (just like my cats try to do with their food bowls). The shrew does not have grinding teeth and the tips of their teeth have a yellowish color when living, at least in New England.

Skull of a Short-tailed Shrew
Northern Short-tailed Shrew

Their size often allows them to escape our attention even though they are fairly common. They, like other ground-dwelling varmints such as mice, voles and moles are considerably active throughout the winter.

New England Vole

How do you know if you have shrews, rather than one of the other rodents? That is, other than seeing them. Shrews, being the smallest mammal also make the smallest hole (1 inch or less). They do not make meandering ridges just under the surface of the ground under snow like voles or moles or create 6 inch round entrance mounds like moles. If I were to catch one, I would find that each front foot of a shrew has 5 toes, where a mouse would only have 4 front toes.

Shew runway along the base of my garden wall

Behaviorally, shrews and voles are much alike. They both make tunnels or pathways in the grass and these runways can be difficult to discern from each other, especially since they will use another animals’ highway complex.

Traditional Shrew Runway in one of my back gardens

The difference is often the size. Shrew pathways which can be located in grass or leaf litter are usually less than an inch in diameter, whereas vole tunnels are slightly larger and usually only in grass. They also landscape their tunnels differently. Voles nip or cut the vegetation on the sides and bottom of their tunnels, sometimes leaving only bare earth. Shrews are less fastidious and the grass will often just be plowed to the side.

Interestingly, shrews are known to have a putrid, musky odor that makes them unpalatable to predators, so usually the only time they are found is after they have met their fate and been abandoned. BTW this is how I knew I had a good chance of finding them in my back yard… Either the fox or a neighborhood cat had clued me in. It is generally believed that the odor is a reproductive marker as it appears stronger during mating. Some shrews that we will find here in Massachusetts include the short-tailed shrew (Blarina brevicauda), least shrew (Cryptotis parva) and the masked shrew (Sorex cinereus).

Shrews are unusual among mammals in a number of respects. They are one of only two land mammals known to echolocate (the other is a mammal from Madagascar that resembles a hedgehog). Unlike most mammals, however, some species of shrew are venomous. Shrew venom is not conducted into the wound by fangs, but by grooves in the teeth. The venom contains various compounds, and the contents of the venom glands of the American short-tailed shrew are sufficient to kill 200 mice if delivered by intravenous injection. Don’t worry though, it won’t kill a human, but it may cause some swelling. Always best not to handle a live shrew without some protection. Just in case you were thinking about going homicidal on your backyard shrews, think again. Like every other living thing on the planet there is always hidden utility. Shrew venom has potential medical use, as one chemical extracted from shrew venom has been demonstrated to show potential for the treatment of blood pressure. Another compound may be useful in the treatment of some neuromuscular diseases and migraines. The saliva of the Northern Short-tailed Shrew (Blarina brevicauda) contains the peptide soricidin and has accordingly been studied for use in treating ovarian cancer. Another interesting factoid…Amazingly, shrews hold nearly 10% of their mass in their brain, which is the highest brain to body mass ratio of all animals (humans included!)

Star Nose Mole often found near wetland areas

Now moles,on the other hand, are just plain funky! The most common foods moles eat include earthworms, insect larva and other soil arthropods. They also eat grubs and plant bulbs but not as voraciously as the vole does. Most mole damage is caused by tunneling in our monotypic lawn, and not by eating plants. Go Moles!!! The most commonly encountered moles are the eastern mole, which causes most of the damage found in yards, and the star-nosed mole, which is mostly found digging tunnels in swampy areas and at deeper levels than the eastern mole. Mole feeding tunnels are usually 2 to 3 inches below the surface.

Mole

Okay, right about now you are thinking that I am absolutely insane because I am happy that I have rodents! Probably true. If they were in my house I would be at Agway right now looking at all kinds of unique ways to remove them from my abode. But what their presence in my yard, and especially in my garden, tells me is that my organic gardening practices are working. I attempt to provide a variety of plants for a variety of native insects. I do not use chemicals or fertilizer formulations other than compost tea or a nature-based organic nutrient source. I leave my leaves and plant structure throughout the winter to provide overwintering area and a food source for the critters. The presence of the shrew means that my garden is beginning to function as a miniature ecosystem with a natural balance of both predator and prey, which on a cold snowy day makes me smile.