iNaturalist is an American 501(c)(3) nonprofit social network of naturalists, citizen scientists, and biologists built on the concept of mapping and sharing observations of biodiversity across the globe.

[5][6] iNaturalist includes an automated species identification tool, and users further assist each other in identifying organisms from photographs and even sound recordings.

iNaturalist began in 2008 as a UC Berkeley School of Information Master's final project of Nate Agrin, Jessica Kline, and Ken-ichi Ueda.

In 2011, Ueda began collaboration with Scott Loarie, a research fellow at Stanford University and lecturer at UC Berkeley.

The website provides tools for registered users to add, identify, and discuss observations, write journal posts, explore information about species, and create project pages to recruit participation in and coordinate work on their topics of interest.

[22][25] Seek by iNaturalist, a separate app marketed to families, requires no online account registration and all observations may remain private.

[26] Seek incorporates features of gamification, such as providing a list of nearby organisms to find and encouraging the collection of badges and participation in challenges.

[22] Any quality of data can be downloaded from iNaturalist and "Research Grade" observations are often incorporated into other online databases such as the Global Biodiversity Information Facility and the Atlas of Living Australia.

[8][28] In addition to observations being identified by others in the community, iNaturalist includes an automated species identification tool, first released in 2017.

[29] Images can be identified via a computer vision model which has been trained on the large database of the observations on iNaturalist.

In the first City Nature Challenge, naturalists in Los Angeles and the San Francisco Bay Area documented over 20,000 observations with the iNaturalist platform.

[43] Users have the option to license their observations, photos, and audio recordings in several ways, including for the public domain, Creative Commons, or with all rights reserved.

As of January 2024, more than 4,000[14] research papers have been published that cite the iNaturalist research-grade observations hosted on the Global Biodiversity Information Facility (GBIF), often in the fields of ecology, conservation, and climate change.

For example, a study in 2019 assessed the relationship between wing coloration and temperature in the dragonfly species Pachydiplax longipennis.