The Truth About Animals…or not?

In The Truth About Animals, Lucy Cooke chose thirteen animal species to explore our changing relationship with animals by telling the story of how our perception of animals has changed in over two thousand years of written history.  Misconceptions about animals have always been a reflection of human culture.  Although scientific methods of studying animals have improved our understanding, we should assume that the “truth” continues to elude us because we cannot altogether escape our tendency to anthropomorphize animals.  We project our own motivations onto animals which often prevents us from accurately observing their behavior outside our own judgmental framework.  We have selected a few examples from Lucy Cooke’s book to illustrate these issues.

Sloth is one of the seven deadly sins

Three-toed sloth in Panama

Human society values hard work, which has prevented us from seeing the sloth as a respectable citizen of the animal world.  In fact, we named the sloth with the intention of insulting it for its lazy life style.  Although the sloth sprawls helplessly on the ground, in the trees, where it lives, it can move from branch to branch with surprising grace and agility, although slowly.  They have fewer muscles than would be needed to move upright on the ground which enables them to hang in the trees while using little energy.  Early explorers to the New World judged the sloth from their perspective as ground dwellers rather than from the sloth’s perspective in the trees.  The sloth’s reputation is not enhanced by being dirty and smelly.

The sloth eats leaves but lacks teeth to chew them.  The leaves are slowly broken down by bacteria in the sloth’s gut and the slowness of digestion is in sync with its slow metabolism and low body temperature.  Sloths have survived for about 64 million years, far longer than the mere 300,000 years of the ancestors of Homo sapiens, proving that they are well adapted to where they live.  The sloth is a survivor, the ultimate test of the success of a species.

Penguins:  Paragons of family values or not?

Emperor penguin family. Creative Commons

People love penguins, primarily because they are cute.  We like their torpedo shaped pint size and the dapper tuxedo they wear.  Neither their shape nor their outerwear were designed to appeal to us.  They are flightless birds that are extremely efficient catchers of fish.  Their wings propel them through the water at speeds of over 30 miles per hour.  Their feet are propellers, steering their quick maneuvers in pursuit of fish.  On land, they are awkward waddlers, which we find endearing.

Their white fronts are less visible to predators in the water when viewed from below with the glare of the light above them.  Their black backs also hide them from being seen in the water from above.

The movie March of the Penguins greatly increased the popularity of penguins partly because it featured a particular species of penguin, the emperor penguin, that is a dedicated father.  The emperor colony trudges deep into the frozen wastes of Antarctica to lay their eggs and hatch their chicks.  When the egg is laid, father penguin puts the egg on top of his feet to keep it off the frozen ice and sits gingerly on it to keep it warm.  Mother penguin promptly leaves because her energy is depleted by producing the egg.  She goes to sea to fish and restore her energy to return 2 months later.  Then they take turns raising the chick and feeding it.

March of the Penguins tried to sweeten the idealized penguin family by claiming that they are monogamous.  In fact, 85% of penguins choose different mates every year.  The time frame for raising the penguin chick is perilously short, allowing no time to hunt for last year’s mate among thousands of lookalikes.

But not all penguin species are scrupulous family members.  Adélie penguins exchange rocks for sex with unattached males.  The rocks are needed to elevate nests above frigid water that can drown eggs and chicks.  And the rocks are at a premium where the penguins nest, so mother penguin makes a deal for the safety of her nest.

Adélie penguins engage in other scandalous sexual behavior that was observed by a scientific expedition in 1911-12:  “They were ‘gangs of hooligan cocks’ whose ‘passions seem to have passed beyond their control’ and whose ‘constant acts of depravity’ run the gamut of masturbation, recreational sex and homosexual behavior to gang rape, necrophilia, and pedophilia.  Chicks were ‘sexually misused by these hooligans,’ including one who ‘misused it before the very eyes of its parent.’  Stray chicks were crushed and ‘very often suffer indignity and death at the hands of these hooligan cocks.’” (1) When the scientific expedition published its report of their findings, these dirty bits were deleted from the publication and kept under lock and key in the museum until being discovered in 2009.

If animal behavior was unseemly in the eyes of early scientists, the public didn’t need to know about it.  I think we can safely assume that there is less such censorship by scientists today, partly because there is greater tolerance for the vast range of sexual behavior among humans.

The mystery of migration


Nesting stork in Morocco, 2013

Ms. Cooke chooses the stork to tell the long story of unraveling the mysteries of migration.  The stork arrives in Europe in early spring which historically coincided with the annual baby boom.  Nine months earlier, on June 21st summer solstice was celebrated with great festivals during which many children were conceived.  This coincidental arrival of storks and babies resulted in the stork becoming a symbol of fertility and childbirth.  A young couple consulting a doctor about their disappointment in not having a child were surprised when told that the stork nesting on their chimney was not a substitute for the sexual encounter they had thought was unnecessary.

Theories about where the storks went when they left their huge nests of sticks were no less imaginative.  In the 17th century an Oxford-educated physics scholar proposed the theory that the storks migrated to the moon:  “’The stork, when it hath bred, and the young fully fledged…all rise together, and fly in one great flock…first near the earth, but after higher…till at last this great cloud…appears less and less by distance, till it utterly disappears.  Now, Whither should be creatures go unless it were to the moon?’”  (1)

This theory was considered an advance over earlier theories.  In the 3rd Century BC, Aristotle had several theories about bird migrations.  His “transmutation” theory suggested that winter robins become redstarts in summer and summer warblers become blackcaps in winter.  His alternative theory was that some birds hibernate in winter.  Actually, the poorwill is the only known hibernating bird. In western North American deserts the poorwill hides in a torpor, avoiding winter food shortages.

Aristotle is the originator of another, particularly persistent hibernation theory.  His belief that swallows spent the winter months at the bottom of lakes and rivers, like fish, is found in “scientific” publications into the 19th century:  “’It appears certain that swallows become torpid during the winter, and even that they pass the season at the bottom of the water in the marshes.’”  (1)

That theory was tested in the 18th century in a series of grisly experiments that cost the lives of many hapless swallows, reminding us that animal rights are a very recent development in science.  On the other hand, we should empathize with early scientists who had little knowledge of the world outside their narrow range of mobility, given limited transportation.  As our world expands so does our knowledge of it.

Pfeilstorch (Arrow Stork)

Ms. Cooke believes the breakthrough in solving the migration mystery occurred in the 19th century when a stork arrived for nesting season with a huge wooden spear lodged in its neck, providing “irrefutable evidence that birds migrate over Africa.”  Ironically, as our knowledge of migration improves, the migration itself is rapidly failing because of anthropogenic (caused by humans) change.

  • Hunting of birds increases as the human population increases and episodically during famines caused by war and crop failures.
  • When farmers in Africa started using pesticides, many storks were killed when they ate poisoned grasshoppers and other large insects.
  • Pollution and drainage of wetlands for farmland caused a sharp decline in Europe’s stork population in the 20th Century:  “The last breeding pair was seen in Belgium in 1895, in Switzerland in 1950 and in Sweden in 1955.” (1)
  • Some migrating birds have quit migrating because the gardened landscapes of humans are more hospitable year around than their winter homes. Flocks of Canada geese are seen year around in the parks and open spaces in the Bay Area.
Canada geese, Lake Merritt, Oakland, California. Oakland Wiki

Ms. Cooke laments:  “[Swallow] numbers along with those of dozens of long-haul bird migrants across Europe, Asia and America, are in perilous decline, thanks to the combined effect of global warming, habitat destruction, hunting and pesticides.  Some scientists have suggested that long-haul migration could soon become a thing of the past.  These amazing avian vanishing acts, which puzzled us for so many generations, could themselves magically disappear, just as they’ve finally been demystified.  (1)

Progress, but humility is still needed

Ms. Cooke concludes that although we know more about animals than we did two thousand years ago, we are undoubtedly still making mistakes and must continually refine our understanding“The quest for truth is a long and winding road, littered with deep potholes.  Thankfully our methods are less brutal than those of our eye-popping past, but we are still stumbling along in the dark and making mistakes.  With the rise of efforts to discredit science, there has never been a greater need for truth.  Yet, wrong turns are an essential part of all scientific progress, which demands blue-sky thinking as it seeks out each new horizon in understanding.  As long as our egos or dogmatic beliefs are not to blame, we should not be afraid to continue to make wondrous mistakes…” (1)

Science is a process that is never done.  We celebrate new discoveries, but we must never think of them as the end of the story.  Our minds must always be open to new information if we are to continue to make progress as humans.

  1. Lucy Cooke, The Truth About Animals: Stoned sloths, lovelorn hippos, and other tales from the wild side of wildlife, Basic Books, 2018

Past & Present Botanical Myths

The conventional wisdom is that human knowledge, especially scientific knowledge, moves inexorably forward.  We are sometimes amused by the misconceptions of the past and marvel at the primitive knowledge of our ancestors.  However, we rarely stop to think that our descendents will probably do the same when they consider our current state of knowledge.

Historical botanical beliefs

"The heads of cowslips, which trembled in the wind, were signed for Parkinson's disease, the 'shaking palsy.'" (1)

The Doctrine of Signatures seemed a logical botanical belief at a time when plants were one of man’s few medicinal tools and religion was a powerful influence in human society.  The Doctrine of Signatures, which was actively promoted by the church in 17th century Europe, was based on a belief that God had “signed” plants with certain suggestive shapes and colors to inform humans of their medicinal properties.  For example, a heart-shaped leaf was considered God’s message to us that a particular plant would be beneficial to the human heart and this message was strengthened by a flesh-colored flower. Every plant was believed to be useful in some way if man could only discern its use.  Else why would they have been created, since the Garden of Eden was created for the benefit of man?  The church encouraged man’s study of plants as a way to worship God’s creation. (1)

Many botanical myths originated from ancient Roman and Greek horticultural treatises and persisted for hundreds of years.  For example a belief in the influence of the moon on plants is first found in the writings of Pliny in first-century Rome and also found in writings as late as 1693:  “[w]hen you sow to have double Flowers, do it in the Full of the Moon.”  (2) 

The origins of many horticultural myths are unfathomable but probably began with a particular event because we often confuse coincidence with causal relationships. (2)

  • Planting bay trees and beeches near  homes will prevent lightning strikes
  • An apple tree that fruits and flowers at the same time is a bad omen
  • The parents of a child who picks red campion will die
  • A pregnant woman who steps over cyclamen will miscarry

Modern botanical beliefs

Now we will turn to the theoretical underpinnings of the native plant movement to see how they are holding up to the scrutiny of current science and ask the rhetorical question, Is it time to relegate invasion biology to the dust heap of discredited science?

The field of invasion biology upon which the modern native plant movement is based, originates with the publication in 1958 of The Ecology of Invasions for Animals and Plants by Charles Elton.  Elton postulated that every plant and animal occupies a different ecological “niche” and plays a specific role within that niche: 

“…every species will have a slightly different role, or niche, and often, he believed, every niche will be filled.  Some animals eat grass, others leaves; some plants grow on wet soil and some grow on dry; some birds nest in dead trees, others in live ones.  When new species are introduced, the theory goes, they can get a foothold and start reproducing only by finding a vacant niche or by throwing some other species out of its niche…” (3)

Elton’s corollary to the exclusivity of the niche is that the introduced species will have a competitive advantage because its predators are absent in its new home.  The predicted result of Elton’s theory was that introduced species will exterminate previous occupants, mass extinctions will occur, and the result will be a simplified ecology composed of few surviving species.

The problem with Elton’s theory is that it doesn’t correspond with reality.  More and more scientists are finding that the frequency of introductions far exceeds the frequency of extinctions.

  • In 2002 Dov Sax reported that introduced species greatly outnumbered extinctions on oceanic islands:  “In the case of plants, islands are now twice as diverse as they were before humans started moving things around.” (3)
  • In 2012, Erle Ellis, et. al., reported that “…while native losses are likely significant across at least half of Earth’s ice free land, model predictions indicate that plant species richness has increased overall in most regional landscapes, mostly because species invasions tend to exceed native losses.” (4)
  • In San Francisco, the second-most densely populated city in the US, ninety-seven percent of the 714 plant species known to exist in San Francisco in 1850 are still found there, despite the fact that most plants and trees in the city are introduced.  (5)

The dire predictions of invasion biology have not come to pass nearly 60 years after their inception.   Many scientists are clearly ready to abandon invasion biology because it does not conform to reality.  Can we finally breathe a collective sigh of relief and move on to a less gloomy view of ecology?  Some day our descendents will look upon this episode in human history and laugh, as we laugh at the 17th century Europeans who examined plants, looking for the clues from God that revealed their purpose.


(1) Richard Mabey, Weeds:  In Defense of Nature’s Most Unloved Plants, Profile Books Ltd, London, 2010, page 87-91

(2) Andrea Wulff, The Brother Gardeners, Alfred Knopf, 2008, page 11-12

(3) Emma Marris, The Rambunctious Garden, Bloomsbury, USA, 2011, page 102-104

(4) Erle C. Ellis, et. al., “All Is Not Loss:  Plant Biodiversity in the Anthropocene,”

(5) Duncan et al, “Plant traits and extinction in urban areas:  a meta-analysis of 11 cities,” Global Ecology and Biogeography, July 2011