The secret life of squirrels in New York City

July 16, 2014 by Lizzie Thelwell, Science Network WA
Species such as squirrels could face increasing urbanisation of habitat, and will have to adapt to urban threats. Credit: 5soulscape

A recent study has found eastern grey squirrels thrive in New York City's urban environment by adapting their behaviour according to cues from human pedestrians, and mostly by ignoring passers-by.

Dr Bill Bateman from Curtin University has spent many years in Manhattan informally and now formally, investigating the behaviour of squirrels to better understand how we can help them survive in cities.

"As urbanisation increases, urban areas around the world may end up being important places for some wildlife," says Dr Bateman.

"It would be good to know what they like about those areas, what allows them to do well and whether we humans want them to be there."

"If we do, we can discover what we need to do to help their continued success."

Researchers investigated squirrels' ability to modify their behaviour when pedestrians show unusual behaviour and tested whether squirrels could discriminate between pedestrians who look directly at them and those who do not.

Squirrels were approached on a trajectory that took the observer within two metres of them and the researchers measured alert distance, flight initiation distance (FID) and distance fled for each individual.

Only five per cent of individuals moved away when the pedestrian remained on the footpath and looked at them. However, when squirrels were approached by a pedestrian who moved off the footpaths and looked at them, 90 per cent of squirrels moved away, with longer FID and flight distance.

Behaviour change allows co-existence with humans

Squirrels reduced their need to make unnecessary responses by modulating their reactions when behaved in a predictable manner and by being sensitive to the direction of humans' attention.

"Behavioural adaptations allow animals of some species to live alongside stimuli and events that we would normally consider dangerous or threatening," says Dr Bateman.

"What is astonishing is that in an iconic urban cityscape like Manhattan, they are doing just as well, if not better, than fellow grey in the woods."

"To a successful urban adapter, a building is the same as a tree, the top of an air conditioner unit is a nesting nook on a branch, a handful of pretzel crumbs are fallen acorns."

Researchers at Curtin and Murdoch University plan to expand on their findings by studying other species' behavioural responses to humans and their activities in different urban environments.

"We need to monitor such species just as we need to monitor in undisturbed areas so we don't see more loss of biodiversity."

Explore further: Study reveals new ways deadly squirrelpox is transmitted to red squirrels

More information: Bateman, P. W. and Fleming, P. A. (2014), "Does human pedestrian behaviour influence risk assessment in a successful mammal urban adapter?". Journal of Zoology. doi: 10.1111/jzo.12156

Related Stories

New hope for the red squirrel

October 16, 2008

A number of red squirrels are immune to squirrelpox viral disease, which many believed would lead to the extinction of the species, scientists have discovered.

Red Squirrels showing resistance to squirrelpox

November 26, 2013

A study by the University of Liverpool has found that the red squirrel population along the Sefton coastline appears to be recovering from a serious outbreak of squirrelpox in 2008.

Study sheds light on squirrel psychology

July 28, 2009

( -- The ability of grey squirrels to learn from observing others is highlighted in a new study. The research shows how squirrels can quickly learn from watching their peers, particularly if it relates to stealing ...

Recommended for you

Making intricate images with bacterial communities

March 19, 2018

Working with light and genetically engineered bacteria, researchers from Stanford University are able to shape the growth of bacterial communities. From polka dots to stripes to circuits, they can render intricate designs ...

Termite queen, king recognition pheromone identified

March 19, 2018

Researchers at North Carolina State University have for the first time identified a specific chemical used by the higher termite castes—the queens and the kings—to communicate their royal status with worker termites. ...

A reference catalog for the rumen microbiome

March 19, 2018

The digestive tracts of ruminant (cud-chewing) animals such as cattle, sheep, and goats convert lignocellulosic plant matter to short-chain fatty acids used for nourishment with unparalleled efficiency, thanks to the activity ...

New life form answers question about evolution of cells

March 19, 2018

Bacteria and Archaea are two of the three domains of life. Both must have evolved from the putative last universal common ancestor (LUCA). One hypothesis is that this happened because the cell membrane in LUCA was an unstable ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.