To Avoid Humans, More Wildlife Now Work The Night Shift


Published:

Red fox under cover of darkness in London. (For use only with this article.)

© Jamie Hall

For their first 100 million years on planet Earth, our mammal ancestors relied on the cover of darkness to escape their dinosaur predators and competitors. Only after the meteor-induced mass extinction of dinosaurs 66 million years ago could these nocturnal mammals explore the many wondrous opportunities available in the light of day.

Fast forward to the present, and the honeymoon in the sun may be over for mammals. They’re increasingly returning to the protection of night to avoid the Earth’s current terrifying super-predator: Homo sapiens.

My colleagues and I have made the first effort to measure the global effects of human disturbance on the daily activity patterns of wildlife. In our new study in the journal Science, we documented a powerful and widespread process by which mammals alter their behavior alongside people: Human disturbance is creating a more nocturnal natural world.

Many catastrophic effects of humans on wildlife communities have been well-documented: We are responsible for habitat destruction and overexploitation that have imperiled animal populations around the world. However, just our presence alone can have important behavioral impacts on wildlife, even if these effects aren’t immediately apparent or easy to quantify. Many animals fear humans: We can be large, noisy, novel and dangerous. Animals often go out of their way to avoid encountering us. But it’s becoming more and more challenging for wildlife to seek out human-free spaces, as the human population grows and our footprint expands across the planet.

Global Increase In Nocturnality

My collaborators and I noticed a striking pattern in some of our own data from research in Tanzania, Nepal and Canada: animals from impala to tigers to grizzly bears seemed to be more active at night when they were around people. Once the idea was on our radar, we began to see it throughout the published scientific literature.

 A badger explores a South London cemetery at night. © Laurent Geslin (For use only with this article.)It appeared to be a common global phenomenon; we set out to see just how widespread this effect was. Might animals all over the world be adjusting their daily activity patterns to avoid humans in time, given that it is becoming harder to avoid us in space?

To explore this question, we conducted a meta-analysis, or a study of studies. We systematically scoured the published literature for peer-reviewed journal articles, reports and theses that documented the 24-hour activity patterns of large mammals. We focused on mammals because their need for plenty of space often brings them into contact with humans, and they possess traits that allow for some flexibility in their activity.

We needed to find examples that provided data for areas or seasons of low human disturbance – that is, more natural conditions – and high human disturbance. For example, studies compared deer activity in and out of the hunting season, grizzly bear activity in areas with and without hiking, and elephant activity inside protected areas and outside among rural settlement.

Based on reported data from remote camera traps, radio collars or observations, we determined each species’ nocturnality, which we defined as the percentage of the animal’s total activity that occurred between sunset and sunrise. We then quantified the difference in nocturnality between low and high disturbance to understand how animals changed their activity patterns in response to people.

For each species, researchers compared the animals’ active periods when people are nearby to when people aren’t around. The distance between the grey and red dot pair for each animal shows how extreme the shift in nocturnality. Reprinted with permission from Gaynor et al., Science 360:1232 (2018). For use only with this article.

Overall, for the 62 species in our study, mammals were 1.36 times as nocturnal in response to human disturbance. An animal that naturally split its activity evenly between the day and night, for example, would increase its nighttime activity to 68 percent around people.

While we expected to find a trend toward increased wildlife nocturnality around people, we were surprised by the consistency of the results around the world. Eighty-three percent of the case studies we examined showed some increase in nocturnal activity in response to disturbance. Our finding was consistent across species, continents and habitat types. Antelope on the savanna of Zimbabwe, tapir in the Ecuadorian rainforests, bobcats in the American southwest deserts – all seemed to be doing what they could to shift their activity to the cover of darkness.

Perhaps most surprisingly, the pattern also held across different types of human disturbance, including activities such as hunting, hiking, mountain biking, and infrastructure such as roads, residential settlement and agriculture. Animals responded strongly to all activities, regardless of whether people actually posed a direct threat. It seems human presence alone is enough to disrupt their natural patterns of behavior. People may think our outdoor recreation leaves no trace, but our mere presence can have lasting consequences.

Future Of Human-Wildlife Coexistence

We don’t yet understand the consequences of this dramatic behavioral shift for individual animals or populations. Over millions of years, many of the animals included in our study have evolved adaptations to living in the daylight.

 Sun bears retreat from the sunny hours when people are nearby.Sun bears, for example, are typically diurnal and sun-loving creatures; in undisturbed areas less than 20 percent of their activity occurred at the night. But they increased their nocturnality to 90 percent in areas of the Sumatran forest where intensive forest research activity created a disturbance.

Such diurnally adapted animals may not be as successful at finding food, avoiding predators or communicating in the darkness, which could even reduce their survival or reproduction.

However, because our mammalian ancestors evolved under the cover of darkness in the time of the dinosaurs, most mammal species possess traits that allow for some flexibility in their activity patterns. As long as animals are able to meet their needs during the night, they may actually thrive in human-dominated landscapes by avoiding daytime direct encounters with people that could potentially be dangerous for both parties. In Nepal, for example, tigers and people share the exact same trails in the forest at different times of day, reducing direct conflict between humans and these large carnivores. Dividing up the day, through what researchers call temporal partitioning, may be a mechanism by which people and wildlife can coexist on an ever more crowded planet.

An increase in nocturnality among certain species may also have far-reaching consequences for ecosystems, reshaping species interactions and cascading through food webs. In California’s Santa Cruz Mountains, coyotes are becoming more nocturnal in areas with human recreation. By analyzing coyote scat, scientists have linked this behavioral change to dietary shifts from diurnal to nocturnal prey, with implications for small mammal communities and for competition with other predators.

Working on this study reminded me that people aren’t alone on the planet. Even if we don’t see large mammals while we’re out and about during the day, they may still be living alongside us, asleep while we are awake and vice versa. In areas where threatened species live, managers may consider restricting human activity to certain times of the day, leaving some daylight just for wildlife.

And it is likely that we need to preserve wilderness areas entirely free of human disturbance to conserve the most vulnerable and sensitive mammal species. Not all animals are willing or able to just switch to a nocturnal lifestyle around people. Those that try to avoid human disturbance entirely may be most vulnerable to the consequences of the expanding human footprint.

Kaitlyn Gaynor, Ph.D. candidate in environmental science, policy and management at the University of California, Berkeley is a wildlife ecologist and conservation scientist. Kaitlyn is interested in better understanding the socio-ecological dynamics of ecosystems to promote human-wildlife coexistence. Her research draws on behavioral and community ecology to understand the roles that humans play in ecological systems, and how humans interact with other large mammal species in shared spaces.

This article was originally published on The Conversation. Read the original article.

See also:
Animals To Humans: Be Quiet, Already
Animals And Plants Evolve Faster In Cities — With Implications For Humans

The Conversation

Edit Module
Edit ModuleShow Tags
Edit Module Edit ModuleShow Tags

Daily Astrology

February 19, 2019

Excitement and motivation are intense. As the Sun dives more deeply into Pisces, the visionary Sign of the Fishes, the Moon gets busy. Luna starts the day in regal Leo. By late morning she’s in diligent Virgo and exactly Full. Mental Mercury is conjunct…
Edit ModuleShow Tags

Alternative Health Directory

Browse all listings »

Edit ModuleShow Tags
Edit ModuleShow Tags

Calendar

February 2019

Celebrating The Love And Valentine’s Week! Come detox, relax and get your romance or couples readings while you recharge in our sanctuary! We have a fun line up of readers and healers...

Cost: 3 service special - $60, single service- $25

Where:
The Healing Power of Flowers - Heaven and Earth
68 Stiles Rd
Unit A
Salem, NH  03079
View map »


Sponsor: The Healing Power of Flowers - Heaven and Earth
Telephone: 603-275-7688
Contact Name: Stacey Smith
Website »

More information

Our outer world is a reflection of what lies within our collective inner worlds. By directing our thoughts in specific, positive ways, we have the potential to guide the world towards becoming a...

Cost: Free

Where:
Inner Space Meditation Center & Gallery
1110 Massachusetts Ave.
Cambridge, MA  02138
View map »


Telephone: 617-547-1110
Website »

More information

Three weekly workshops with Ayal will be offered on February 10, 17, 24 from 10:30 to 11:30am In this meeting, we will talk about sleep and remind or teach simple techniques for an easier...

Cost: $20

Where:
Sohum Yoga and Meditation Studio
30 Lyman Street, Suite 108B
Westborough shopping center
Westborough, MA  01581
View map »


Sponsor: www.SOHUM.org
Telephone: 508-329-3338
Contact Name: Ritu Kapur
Website »

More information

Show More...
Show Less...
No Events

MBSR: Mindful Based Stress Reduction Learn how to tap into your inner well of strength, peace, and ease. Mindfulness, as taught in the MBSR program, is recognized worldwide as the gold...

Cost: Free

Where:
Enlightened Interventions
25 Union St.
Worcester, MA  01608
View map »


Sponsor: The Center for Resilient Living
Telephone: 508-556-7022
Contact Name: Ginny Wholley
Website »

More information

Show More...
Show Less...

Wednesday, February 20th–Saturday, February 23rd 9am-3pm each day Experience transformation guided by Mother Mary. Through Divine vibration, you will be aligned for quicker healing and...

Cost: $500

Where:
, MA


Sponsor: The LoveLight Center
Telephone: (207) 216-9584
Contact Name: Cheryl Banfield

More information

Discover how you can release tight muscles and improve range of motion in locked joints in a weekly ESSENTRICS stretch classes led by Raindrop Fisher, certified Essentrics instructor. Raindrop is a...

Cost: $10 drop-in / $100 for 12 classes

Where:
Village at Waterman Lake
Function Room - Chalet Bldg
715 Putnam Pike
Greenville, RI  02828
View map »


Sponsor: Healthier Fit Lifestyle
Telephone: 401-678-0950
Contact Name: Raindrop Fisher
Website »

More information

Show More...
Show Less...

ESSENTRICS with Raindrop is a dynamic, one-hour, slow-movement stretch and strengthening class that uses all the muscles of the body to liberate stiff joints and rebalancing the body so that you...

Cost: $5 donation

Where:
Pascoag Public Library
57 Church Street
Pascoag, RI  02859
View map »


Sponsor: Healthier Fit Lifestyle
Telephone: 401-678-0950
Contact Name: Raindrop Fisher
Website »

More information

This 8 week series in Tai Chi will provide you with everything you need to get started in a personal Tai Chi practice. Just for Beginners—there is no expectation, and no pressure in...

Cost: $137 for 8 weeks

Where:
Spiral Path Connections
218 Boston Street
Unit 104
Topsfield, MA  01983
View map »


Sponsor: The Spiral Path
Telephone: 978-314-4264
Contact Name: Johanna Hattendorf
Website »

More information

With Sherri Snyder-Roche. This yoga workshop will explore self-compassion, self-love and pushing through discomfort to help your recovery process. Recovery from divorce, eating disorders,...

Cost: $95 for 6 weeks or $17 drop in

Where:
State of Grace Yoga and Wellness Center
104 E. Hartford Avenue, Unit A
Uxbridge, MA  01569
View map »


Telephone: 508-278-2818
Website »

More information

Show More...
Show Less...

“Master your breath, let the self be in bliss, contemplate on the sublime within you.” —Krishnamacharya Join us for an evening of deep exploration and transformation using the...

Cost: $30 (some hardship rates available)

Where:
Spontaneous Celebrations
45 Danforth Street
Jamaica Plain, MA  02130
View map »


Telephone: 617-233-6410
Contact Name: Allen Howell, M.Ed.LMHC
Website »

More information

Show More...
Show Less...

Great readings at a great rate - only $20 for 15 minutes. Join us for a great day with lots of specials too! Featuring Amit’s Tibetan Singing Bowls and Silver Jewelry Sale!...

Cost: $20 for a 15 minute reading

Where:
Circles of Wisdom
386 Merrimack Street
Suite 1-A
Methuen, MA  01844
View map »


Sponsor: Circles of Wisdom
Telephone: 978-474-8010
Contact Name: Cathy Kneeland
Website »

More information

This workshop will be a wonderful and interactive experience for parents and their child. You will:  1. Learn the importance of developing focus through basic mindfulness exercises....

Cost: $40

Where:
Sohum Yoga and Meditation Studio
30 Lyman Street, Suite 108B
Westborough shopping center
Westborough, MA  01581
View map »


Sponsor: www.SOHUM.org
Telephone: 508-329-3338
Contact Name: Ritu Kapur
Website »

More information

Join us as we herald in the month of love with the archangels! It will be an evening of healing and soul replenishment. Our event will open with a brief message of love and support from the...

Cost: $40

Where:
private office
North Andover, MA  01845


Sponsor: Diana Harris
Telephone: 978-973-6637
Contact Name: Diana Harris
Website »

More information

6 Saturdays 10am–11:30am February 23–March 30, 2019 Taijiquan (Tai Chi ) is a healing martial art, using breath and movement together to strengthen the body and quiet...

Cost: $120

Where:
Metta Wellness
679 Pleasant Street
Paxton, MA  01612
View map »


Sponsor: Metta Wellness
Telephone: 774-245-5487
Contact Name: Rick Rocha
Website »

More information

Show More...
Show Less...
Edit ModuleShow Tags
Edit Module Edit ModuleShow Tags