The Largest Gatherings in the World
Humans are not part of a regular diet for any animal. Nothing hunts humans. That’s big.
Pretty much every other animal lives in fear of being eaten. There is a constant search for food and water, taking some species on migratory routes spanning thousands of miles.
We humans have mastered our environment so that now we can enjoy strawberries in the middle of a blizzard. But our impact goes way beyond strawberries — our growth and industrialization have outpaced the ability of other animals to adapt. Many species are losing their homes, or running out of food to eat.
The extinction of a species halfway around the world feels too distant to have any sort of impact on how we live day-to-day. Try thinking of extinction like this: Imagine that banks everywhere decided to stop selling mortgages. No loans, just cash in order to buy a house. It’d be chaos, right? Very few people have hundreds of thousands of dollars just sitting around. Everyone would need to go on extreme budgets, which would kill the retail and entertainment industries. That much job loss would be catastrophic. The same can be said for natural ecosystems: Rising ocean temperatures have lead to death of corals, leaving less habitat for many species of fish, resulting in millions of fishermen around the world struggling to provide for their families.
It’s easy for us to forget how dependent we are on our environment when living in cities. It takes something big for us to pay attention. The Guardian covered the bleaching of the Great Barrier Reef with many tragic, unprecedented photographs. A year later, the situation has only become worse. Many others have chronicled the recent hardships facing countless animals, yet — at least in the U.S. — man-made climate change is still hotly debated. This is one of the causes that emboldened scientists and advocates of reason to take to the streets and march. Maybe this could be the big event that would signal to politicians that science-based policies are important to them.
I marched in Madison, Wisconsin, overjoyed at the camaraderie I felt. I was surprised to see the crowd size was only estimated at 5,000 people, though. Surely we had more than that?
Jeremy Pressman and Erica Chenoweth, professors at the Universities of Connecticut and Denver, decided to start tallying up how many people attend various marches and protests starting with the Women’s March. They created the Crowd Counting Consortium. It turns out that somewhere between 334 and 525 thousand people marched for science around the world, but even more impressive is the 3.5 to 5.6 million people at the first Women’s March.
The immediate result of these marches was the broad media coverage. Such events are good ways to bring important issues into our national dialogue. But what about the long-term effects? We surely didn’t change the minds of climate change deniers overnight, so I can’t help but wonder if we recruited enough people to march for our cause?
Many of the largest gatherings of humans tend to be for religious purposes. The Hindu pilgrimage Kumbh Mela in Allahabad, India lasted two months in 2013 and brought up to 120 million people to bathe in Ganges and Yamuna rivers. Words and pictures surely don’t do justice to what this event was like to attend.
Humans are the dominant species on our planet so it should be no surprise that we have the largest gatherings. Except… we don’t. It’s not even close.
Animals come together at massive scales to find food and water, to find mates and raise their young, and for the safety of numbers (to be read in David Attenborough’s voice). It’s these herds and flocks numbering into the millions that we can notice the biggest effects from human activity.
I wanted to be able to write a story about how the March for Science is shaping up to have an impact on public policy in the U.S., but that may not happen in the near future. What will happen if we do nothing is the decline of animal populations. That’s something we can measure. Our notion of a human-dominated world is challenged by the sheer majesty of nature. However, through measuring animal populations we have clear evidence at just how susceptible nature is to human influence.
The following infographic illustrates how much larger animal gatherings are compared to humans. Some of the most notable declines in animal populations are noted in the details below, along with sources.
Details and Sources
30 thousand — Red-sided garter snake
The Narcisse snake dens in Manitoba, Canada can each contain up to 30 thousand snakes. There are about 70 such caves in Manitoba, and each cave in about the size of a typical living room.
200 thousand — Western Arctic Circle caribou herd
There are four large herds of caribou in Alaska and Canada. The largest is the Western Arctic Circle, which has seen it’s population decline from 490 thousand in 2003 to 201 thousand in 2016.
250 thousand — Mongolian gazelle herd
Continuing on with our theme, large grasslands give rise to large populations of grazers. The largest gathering of gazelle was seen in eastern part of the Eurasian Steppe.
350 thousand — March for Science
Washington D.C. and Chicago were both estimated at around 40 thousand people each. The view-only spreadsheet with estimates for every city can be accessed here.
1.5 million — Eared grebe migration
Mono Lake in California is the location where half of North America’s eared grebe population stops on their migration south each year.
1.5 million — Wildebeest migration
The Serengeti Plains of Africa span some 12,000 square miles and are home to one of the most iconic migrations because of the treacherous, crocodile-filled water crossings.
4 million — Women’s March
The Women’s March in Washington D.C. was the largest and had between 470 and 680 thousand attendees. Numbers for each location were derived from police estimates, news sources, social media and photographs, with high and low estimates to reflect the amount of uncertainty. Erica Chenoweth gives a more thorough breakdown of their methodology in this Washington Post article.
6 million — Pope Francis visits Manila, Philippines in 2015
In a country where 81% of the population are Catholics — about 76 million people — a visit by Pope Francis was a once in a lifetime opportunity. He was invited by Cardinal Luis Tagle, and the theme of his visit was “Mercy and compassion.”
20 million — Short-tailed shearwater migration
Short-tailed shearwaters and sooty shearwaters make some of the longest migrations in the world. Birds have been tracked on loops from Tasmania and New Zealand to Alaska and Japan (and back again) totaling 30,000 to 64,000 km annually (up to 40,000 miles), depending on the species. These birds follow the seasonal patterns of plankton blooms, which also draw krill, fish, and as pictured above, humpback whales.
30 million — Kumbh Mela in Allahabad, India in 2013
There are four fairs in India recognized as Kumbh Melas — Allahabad, Haridwar, Nashik and Trimbak — occurring every 12 years at each site. The meaning of the festivals is “the confluence of all our cultures. Kumbh is the symbol of spiritual awakening.”
30 million — Mexican free-tailed bat
The largest gathering of mammals occurs in Bracken Cave near San Antonio, Texas. Some 20–40 million Mexican free-tailed bats use this cave to raise their young.
38 million — Tokyo Metropolis population in 2016
Tokyo is technically not a city but a prefecture of Japan and contains 23 wards. Its population is comparable to the entire state of California but contained in an area only slightly larger than the Los Angeles metropolitan area.
40 million — Red crab migration
Islands are often the easiest places to identify the impact of humans. Christmas Island is an Australian territory near Indonesia where native species have evolved over thousands of years but are now being confronted by invasive species brought in by humans. The “crazy ant” Anoplolepis gracilipes is estimated to have killed 10–15 million red crab in the past few years, or about 1/3 to 1/4 the total population.
120 million — Monarch butterfly migration
These 4-inch creatures migrate up to 3,000 miles from October to March each year. Compared by size, this would be the equivalent of a human travelling ~51 thousand miles, or going around the Earth twice. Monarchs amass in central Mexico in numbers that literally blanket trees, huddling for warmth. It is heralded as one of the most spectacular migrations on the planet, yet every year since 1994–95 the overwintering population has declined by 9%. Increased logging in Mexico has led to habitat destruction, while urbanization in America with volatile weather has led to less food sources along the journey. These butterflies are important pollinators and help establish the base of the food chain for many other animals, so their extinction would cause irreparable harm.
55 billion — Locust swarm
Locusts have been the most iconic pest to mankind since biblical times, or earlier. Their unfathomably large swarms decimate any vegitation and crops in their wake, which can cause hundreds of millions of dollars in damage to countries’ agriculture industries. The Rocky Mountain locust serves as a prominent example of how quickly a species can become extinct — estimated between 1875 and 1902. As farmers moved west they plowed the fertile grounds that the locust used to lay their eggs, likely leading to the sudden extinction. It’s hard to argue that this was a bad thing for us. Likely there were significant declines in the populations of birds and other animals that ate locusts in North America, but less competition for food also means other insect populations could thrive. The impacts of this extinction were not fully measured, so if anything this serves as a wake-up call for us to be conscious of how our actions affect other animals and the environment.
100 billion — Argentine ant supercolony
The Argentine ant has caused quite the kerfuffle among scientists questioning what exactly constitutes a colony. Throughout this article we have progressed to larger gatherings of animals with less definitive boundaries. Generally we stuck to groupings of herds, or colonies, or swarms, or migratory populations. The Argentine ant is best classified to exist in supercolonies — a term invented to describe ant populations. The largest supercolony represents numerous related colonies spanning 6,000km along the Mediterranean coast, likely representing billions to trillions of individuals.
Even this may be a low estimate. More recent findings suggest that we need a new term — megacolony — to describe how these supercolonies on different continents appear to be both friendly and genetically similar to each other. Sure, the Argentine ant is an invasive species, but their global “cooperation” remains unparalleled by any other animal species.
Credits
Icons — The Noun Project
Yi Chen, Vishal, Yugu Design, Parkjisun, Jack Magma, Store Black, Ranjit Kumar, Roselin Christina, Paul Jessop and Yo Baba.
Sharing
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