Hoarding is a general term for a behavior that leads people or animals to accumulate food or other items during periods of scarcity.
Hoarding and caching are common behaviors in many bird species as well as in rodents. Most animal caches are of food. However, some birds will also stingily collect other items, especially if the birds are pets. Magpies are famous for hoarding items such as money and jewelry, although research suggests they are no more attracted to shiny things than other kinds of items. Human hoarding may be related to animal hoarding behavior.
Civil unrest or natural disaster may lead people to hoard foodstuffs, water, gasoline and other essentials which they believe, rightly or wrongly, will soon be in short supply. Survivalists, also known as preppers, often stockpile large supplies of these items in anticipation of a large-scale disaster event.
Some hoarding in humans may be a form of mental illness, specifically obsessive-compulsive disorder (OCD), where the perceived importance of the hoarded items far exceeds their true value. Humans may lose the desire to throw away unneeded items because of a feeling of attachment to these items. In severe cases, houses belonging to such people may become a fire hazard (due to blocked exits and stacked papers) or a health hazard (due to vermin infestation, excreta and detritus from excessive pets, hoarded food and garbage or the risk of stacks of items collapsing on the occupants and blocking exit routes). 
- Hoard (archaeological)
- Hoarding (economics)
- Compulsive hoarding
- Collyer brothers, rich eccentrics who were noted for compulsive hoarding
- Plyushkin, fictional Russian hoarder
- Andrews-McClymont, Jennifer G.; Lilienfeld, Scott O.; Duke, Marshall P. (Dec 2013). "Evaluating an animal model of compulsive hoarding in humans". Review of General Psychology 17 (4): 399–419. Retrieved 16 April 2014.
- Mayo Clinic hoarding definition
- Anxiety Disorders Center/Center for Cognitive Behavioral Therapy: Compulsive Hoarding, Hartford Hospital
- "Hoarding", Mayo Clinic, 2012. Retrieved 2013-05-19.
- Hoarding, Audrey Wright
- Tolin, David; Frost, Randy; Steketee, Gail (2007). Buried in Treasures: Help for Acquiring, Saving, and Hoarding. Oxford: Oxford University Press. ISBN 978-0-19-530058-1.
- Neziroglu, Fugen; Bubrick, Jerome; Yaryura-Tobias, Jose (2004). Overcoming Compulsive Hoarding: Why You Save & How You Can Stop. California: New Harbinger. ISBN 978-1-57224-349-1.
- Steketee, Gail; Frost, Randy (2006). Compulsive Hoarding and Acquiring: Workbook. Oxford: Oxford University Press. ISBN 978-0-19-531055-9.
- Steketee, Gail; Frost, Randy (2006). Compulsive Hoarding and Acquiring: Therapist Guide. Oxford: Oxford University Press. ISBN 978-0-19-530025-3.
- Steketee, Gail; Frost, Randy (2011). Stuff: Compulsive Hoarding and the Meaning of Things. Oxford: Oxford University Press. ISBN 978-0547422558.