Black Squirrels
Even the most common critters in nature can have aspects, behaviors, or characteristics about them that I find amazing, and I am hoping you might also. The Eastern Gray Squirrel (Sciurus carolinensis) has got to be one of the most common and overlooked critters in America. They are found throughout the entire eastern half of the country, and a nearly identical cousin is found in the western half. So, the other day, when I was driving back from a presentation I had given about nature to a large group at a college, I spotted an Eastern Gray Squirrel black morph, and I thought, here is an extremely common critter with so many cool stories to tell. Black Squirrels are the melanistic variation of the Eastern Gray Squirrel. In other words, they are just a regular old Eastern Gray Squirrel, but happen to have extra melanin in their fur that makes them black. Melanin is just a pigment in the fur. So, the question is, why are they black? While we may never know why, there are some observations that we biologists can make. Black Squirrels can be found throughout the range of the Eastern Gray Squirrel, but the Black Morphs tend to be more frequent in the northern portions of its range, especially around the Great Lakes Basin. For example, the Black Morph forms the majority of the population in the Canadian province of Ontario and the state of Michigan. During the 19th and 20th centuries, the Black Morphs were introduced to many places across the eastern half of the country because people liked the way they looked. Many cities, municipalities, schools, and parks have adopted the Black Squirrel as their mascot as a symbol for their community, and some have even passed ordinances that protect the Black Squirrels. The dark fur is believed to come from a variant pigment gene. A study in 2014 showed how the pigment gene can be the determining factor in whether the squirrel will be gray or black. Another study points out that the variant pigment gene was originally found in dark morph Fox Squirrels. Fox Squirrels (Sciurus niger) are another tree squirrel found in much of North America. The pigment gene jumped from the Fox Squirrel to the Gray Squirrel after an interspecies mating occurred centuries ago. Some research shows there are some benefits to the Gray Squirrel having black fur (melanistic). One theory is that Gray Squirrels have an advantage of better concealment in deciduous (trees with leaves) forests, while Black Squirrels have the advantage of concealment in conifer (trees with needles) forests, which are found in more northern states. In addition, another study in 1989 showed that the gray morph had better concealment while sitting still, while the black morph had better concealment while in motion. The second theory for dark fur is thermoregulation. Studies show that black furred squirrels had an 18 percent lower heat loss when the outside temperatures fell below 14° F, along with a 20 percent lower metabolic rate. So, this suggests that the black coat gives an advantage in northern regions. So, what determines if a mating pair of squirrels produces black offspring? Gray Squirrels have two copies of the gray pigment gene, and Black Squirrels have either one or two copies of the black pigment gene. If a Black Squirrel has two copies of the black gene, the offspring will be jet black in color; if it has one copy, it will be a brownish-black. Only around 10 percent of the Eastern Gray Squirrel is believed to be jet black. In areas with many Black Squirrels, litters of mixed colored offspring, being gray, grayish black, and jet black are common. As you can see, there are so many interesting things to consider in even the most common of our wild critters. Now multiply this by the number of cool critters on the planet, and you can see we are surrounded by amazing and fascinating behaviors and characteristics of even the most common animals. Until next time… Stan Tekiela is an author, naturalist, and wildlife photographer who travels extensively to study and photograph wildlife. He can be followed on Instagram and Facebook. He can be contacted via his website at naturesmart.com.
American Bison
The American Bison (Bison bison) is one of those animals that doesn’t seem to get the admiration or respect that other large animals command. Brown Bears, Moose, and Elk are adored by the masses. White-tailed Deer are prized, and Black Bears are respected, and yet it seems the Bison is just tolerated, kind of like you might tolerate your strange uncle that comes to a family gathering. Bison are the national mammal of America, and it seems rather fitting. The Bison has a significant historical, cultural, and ecological importance and does a great job at representing the strength of America. This critter has gone from being one of the most numerous animals in America in pre-settlement times, to being at the brink of extinction, and is now rebounding. It has an important conservation success story to tell and a good lesson to learn. The American Bison is the largest land mammal in North America. This was painfully obvious to me while I was recently filming and taking pictures of some Bison in Teddy Roosevelt National Park in North Dakota. The males were rutting and tending very closely to some females. Looking through my camera lens brings the animal up close and personal and really drives home the fact that the males are absolutely huge. An adult male can stand over 6 feet tall at the shoulder and is 10 to 11 feet in length. Females and young males are much smaller, but an adult male can weigh over 2,000 pounds (one ton). The record heaviest bison weighed over 3,800 pounds. Despite their massive size, they are super-fast and can even outrun a horse, reaching 35 mph and jumping over six feet high. This is definitely not an animal to trifle with. I was following one particular large bull when I noticed he wanted to cross a road. The sides of the highway had the standard metal guard rail, which is only about 3 feet tall, but this bull didn’t even break stride and cleared the rail in one clean jump and kept going. Bison are considered ecosystem engineers, similar to the Prairie Dog that I wrote about last time. The bison don’t just graze; they shape the environment around the areas where they roam. Moving around the Bison encourages a wide variety of plants to grow by grazing for a short time before moving onto another area. They are one of the few species where both the males and females have horns. Just a reminder, horns are different from antlers. Horns are permanent structures on the animal’s head and are composed of keratin, compared to antlers, which are made mostly of calcium and are regrown each year. I was out filming a herd of Bison, which contained several very large males, all of who were rutting. During the breeding season, the males go around and check in with females. They smell the female to determine if she is near the optimal time to be bred. As the males wander around, they sound off with a deep and resounding bellow. These bellows are very loud and sound like a cross between a lion’s roar and a Black Bear’s growl. The low wave frequency of the bellows travels well across the open ground. I happen to notice the sides of the Bison vibrating with each bellowing call, just where the ribs are located, so much that the dirt and dust in the male’s fur vibrated right out into the air. It was a truly impressive sight to see and something I would never have known about or understood if I wasn’t spending so much time observing and filming. We should celebrate our American Bison because it’s truly a unique American animal. By the way, I hope you noticed that I never called them Buffalo. This is because they are not a type of Buffalo. Also, Saturday, November 1st, is National Bison Day and Awareness Day. This day of celebration is the first Saturday in November each year. Until next time… Stan Tekiela is an author, naturalist, and wildlife photographer who travels extensively to study and photograph wildlife. He can be followed on Instagram and Facebook. He can be contacted via his website at naturesmart.com.
Prairie Dogs
Diversity is the key to the strength and resilience of Mother Nature. Diversity in the plant world ranges from single-celled plants, known as algae, to giant sequoia trees. The diversity of insects is almost too much to even fathom. Birds are wonderful examples of the diversity of nature. Over 11,000 different species of birds flit around the world in so many vibrant colors, shapes, and sizes. The mammals of the world are no exception to the marvels of diversity. Over 6,600 distinct species of mammals add to the diversity of Mother Nature. There are mammals that swim in the deepest oceans, live underground, in the deserts, forests, and wetlands. We even have mammals that fly. Each one of these species plays an important role in the health and diversity of our natural world. You can think of each and every species of plant, insect, fungi, bird, or mammal as an individual rivet on an airplane. This metaphor was first developed by Paul Ehrlich and is known as the Rivet Popper metaphor. The metaphor is used to explain the importance of biodiversity and the consequences of species extinction on the stability of our ecosystems. Thousands of rivets hold the plane together, just as thousands of species hold our ecosystems together. Some rivets are more vital than others to the plane’s ability to fly. If you lose a couple of rivets, the plane can continue to fly, but at what point and how many rivets are too many and cause the plane to crash? Depending upon where on the plane a rivet is lost will determine the viability of the plane. The important ones are considered keystone species. The Rivet Popper illustrates that while the extinction of one species might not cause the plane to crash, the cumulative loss of biodiversity, especially the loss of a keystone species, increases the chances of the eventual collapse of the ecosystem, or the plane to crash. Keystone species are so important to a given ecosystem. Often these keystone species are small, unnoticed, and seemingly unimportant. Some people may even question, “What good are they?”. The Black-tailed Prairie Dog (Cynomys ludovicianus) is one of these species that plays an integral part in the grassland ecosystem. I was thinking about this last week while capturing some images and video of these marvelous creatures while photographing in western North Dakota. Prairie Dogs are “ecosystem engineers” of the grassland habitat. The list of benefits of their existence will be too much to include in this column, but let me highlight a few. Dozens of other species literally depend upon prairie dogs. The complex burrows that the dogs dig create homes for many other species, such as Burrowing Owls and the endangered Black-footed Ferret. Other critters, such as snakes, beetles, mice, voles, and others, also use their burrows. Their digging also improves the soil health by aerating the soil, turning over the soil to recycle nutrients and helping rainwater recharge the aquifers, and preventing flooding and excess runoff. Their constant grazing on the vegetation that surrounds the prairie dog towns promotes new growth that benefits other grazers such as Bison and Pronghorn. Dozens of other animals depend upon Prairie Dogs for food. Predators such as hawks, eagles, foxes, and coyotes often depend upon Prairie Dogs for food. The American Badger and Black-footed Ferrets almost exclusively feed on Prairie Dogs. Bobcats and Swift Foxes spend a lot of time hunting them also. The diversity of life surrounding a Prairie Dog town is undeniable. Outside the Prairie Dog town, you just don’t see the wide variety of plants and animals, especially the predators. A healthy Prairie Dog town is the heart and soul of a healthy and productive ecosystem. Every time I visit a Prairie Dog town, I am reminded of just how important diversity is for a healthy environment. Until next time… Stan Tekiela is an author, naturalist, and wildlife photographer who travels extensively to study and photograph wildlife. He can be followed on Instagram and Facebook. He can be contacted via his website at naturesmart.com.