Thoreau was a student of nature for virtually all of his adult life. During Thoreau's life, Cape Cod was a relatively unspoiled area rich with nature and people who worked closely in nature, such as farmers and fishermen. Those who lived on Cape Cod tended to be independent sorts, and Thoreau preferred their company to those of people engaged in commerce or other business-related occupations.
In his small book Cape Cod, Thoreau recounts his experiences on walking excursions around Cape Cod during the mid-1800's. In the process he described much about the unspoiled nature present throughout the Cape at that time.
In the opening chapter Thoreau talks about the ecology of living along the ocean: in the midst of a desperate sight - the wreck of a boat loaded with immigrants, most of whom drowned, he saw people gathering seaweed to use as fertilizer. The seaweed had been tossed up on the shore by the same storm that sank the ship. Thoreau valued such practical use of what nature had to offer.
His unusual perspective about both people and nature is revealed in this sentence: "I sympathized rather with the winds and waves, as if to toss and mangle these poor human bodies was the order of the day. If this was the law of Nature, why waste any time in awe or pity?" The statement seems insensitive but reveals his deep love of nature in all its forms.
Throughout the book, Thoreau notes things that we would celebrate today, such as exceptionally clean water. He describes swimming in such water with great delight, and comments on the fish he can see clearly swimming around his feet. This suggests that fish were more bountiful then than now, as well as the water cleaner. He also notes the thorn-apple growing around the edges of a small island, suggesting an ecological balance, with the plant helping fight the erosion of the little island.
As Thoreau begins the walking portion of his trip, he describes the effects of the environment - a sand bar thrust out into the ocean - on the plants of the area. He describes the area as barren, with few trees except for occasional isolated trees and apple groves. He notes how the windswept nature of the land affected development of the trees. Many had flat tops or branched from very low on the ground, suggesting that the trees had adapted to the danger of the fierce storms by reshaping themselves. No doubt pruning from storms affected this process. He described these events as "habits of growth." He noted that apple groves on the Cape had trees no taller than a man, with no ladders needed to pick the apples. Presumably this demonstrates some natural selection. It seems unlikely that the settlers planted only apple trees. Instead, it seems possible that apple trees adapted best to the environment of Cape Cod. Later in his book he notes other trees that grow smaller than they do on the mainland as well, including oak and pine.
Further down the cape, he came to clam fields. He was told the local wisdom that clam beds should be 'stirred" with sticks regularly to encourage the clams to not crowd themselves, but Thoreau remained skeptical, and noted that although the locals believed the supply of clams to be infinite, Thoreau believed that at least one variety (Mya arenaria) was already less abundant than it had been in times past. Thoreau had noted mankind's effects on the ecology.
Further on his walk, Thoreau makes note of several different kinds of seaweed and the environments that grow them. He noted very few if any stones near Wellfleet, and observed that he also saw no rockweed, a water plant that anchors itself to rock. He saw masses of kelp in the water, and cut some to study its structure.
Thoreau spoke poetically about the birds he observed along the coast, noting their differences to woodland songbirds:
Mackerel-gulls were all the while flying over our heads and amid the breakers, sometimes two white ones pursuing a black one; quite at home in the storm, though they are as delicate organizations as sea-jellies and mosses; and we saw that they were adapted to their circumstances rather by their spirits than their bodies. Theirs must be an essentially wilder, that is, less human, nature than that of larks and robins."
While staying with a local oysterman in Wellfleet, Thoreau again demonstrates his ability to learn about the biology and ecology of the area. In his long walk toward Provincetown, he finds lots of Native American arrowheads, evidence that Native Americans once lived in the area. The beach was covered with clam and oyster shells, and it was clear to him from his observations that it was the fish and shellfish that drew the earliest inhabitants there. He talked about the behavior of oysters and clams in the wild, including reports of very large clams called quahogs capturing birds' feet in its shell, drowning the bird. He noted that not all "common knowledge" was accurate. The oysterman told him that part of a quahog had to be removed because it was poisonous, but Thoreau noted that he had eaten an entire one without becoming sick. Throughout the journey, Thoreau was always analyzing what he learned about the ecology around him, comparing it to previous knowledge. He listened to what the local people had to say but scrutinized it for accuracy. He demonstrated a scientific mind.
Thoreau listed in some detail the great variety of bivalves he found. He was already well informed about the varieties, and where they might be found, but he described their differences clearly. He listed giant clams, barnacles, the smaller, Mya arenaria frequently eaten, mussels, scollops (perhaps what we call scallops?), cockles, and other varieties. He saw the shells of horseshoe crabs and lobsters. Clearly he wondered about the variety and diversity. The Origin of the Species had not yet been published, but any evolutionist would be fascinated to see so many varieties of one type of animal all living in the same ecology. He noted similar variety of plants on the shore in some places, and noted that different plants lived in different circumstances.
Later in the book he notes the ease with which lobsters were caught. The lobstermen simply had to throw their nets to the bottom of the sea, and the lobsters would grab hold and not let go. This causes the reader to consider again that over-fishing has likely significantly reduced lobster numbers from Thoreau's time.
He also foreshadowed the concept of evolution in this statement: "It is well-known that different fishes even of the same species are colored by the water they inhabit." He noted the role that even the smallest animals played in the ecology. He noted, for instance, that sand-fleas can devour a dead fish quite rapidly.
In addition he noted the differing behavior of birds as well as variations in their appearance, including birds with long, narrow beaks for burrowing in the sand and smaller birds that had the ability to hover of the water, dodging the breaking waves but picking off food from the surface.
He also tells of some ecological history of the Cape, reporting that the residents told him that at one time it was forested, but that many trees have been cut down. At that time the cape had woodland animals such as deer, demonstrating how humans can change the ecology around them. He noted efforts to reforest some areas with pine.
Thoreau described a whaling practice where fishermen went out and drove herds of small whales, possibly pilot whales, into the shore, to harvest the blubber. He saw nearly 200 carcasses on one beach. It certainly raises the question of over-harvesting in the mind of the reader. The image sounded a little like what we heard about buffalo massacres on the Western plains, which nearly pushed the American bison to extinction.
About the ocean, Thoreau said,
Though once there were more whales cast up here, I think that it was never more wild than now. We do not associate the idea of antiquity with the ocean, nor wonder how it looked a thousand years ago, as we do of the land, for it was equally wild and unfathomable always. The Indians have left no traces on its surface, but it is the same to the civilized man and the savage. The aspect of the shore only has changed. The ocean is a wilderness reaching round the globe, wilder than a Bengal jungle, and fuller of monsters, washing the very wharves of our cities and the gardens of our sea-side residences..."
He also noted the power of the natural world over humankind's futile attempts to control it as well as the damage we do in endangering species when he said, "Serpents, bears, hyenas, tigers, rapidly vanish as civilization advances, but the most populous and civilized city cannot scare a shark far from its wharves." It…